1 Icacm Abs Book

st INTERNATIONAL CONFERENCE

ON ADVANCED CONSTRUCTION

MATERIALS

BOOK OF ABSTRACTS

Editor: Konstantin Sobolev and Academic Group on Concrete Technology

Biblioteca Universitaria

“Raúl Rangel Frías” Monterrey, NL, México

December 3-6, 2006

AMERICAN CONCRETE INSTITUTE

SECCIÓN NORESTE DE MÉXICO, A. C.

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1st International Conference on Advanced Construction Materials

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STEERING COMMITTEE

President: José Antonio González Treviño (UANL) General Secretary: Jesús Ancer Rodríguez (UANL) Academic Secretary: Ubaldo Ortíz Méndez (UANL) Principal, Facultad de Ingeniería Civil: Oscar Moreira Flores (UANL)

CONFERENCE ORGANIZATION

Chairman: Konstantin Sobolev (UANL) Secretaries: Iliana M. Garza and Jessica Saucedo Flores (UANL) Treasurer: Carlos Arizpe (UANL)

INTERNATIONAL SCIENTIFIC COMMITTEE

• Pierre - Claude Aïtcin (University of Sherbrooke) • John E. Bolander (University of California - Davis) • Theodore W. Bremner (University of New Brunswick) • Domingo Carreira (Illinois Institute of Technology) • Ignasi Casanova (Technical University of Catalonia) • Pedro Castro (CINVESTAV) • Kamal H. Khayat (University of Sherbrooke) • Richard E. Klingner (The University of Texas at Austin) • Paulo Helene (Universidade de Sao Paulo) • V. M. Malhotra (CANMET) • Barzin Mobasher (Arizona State University) • Tarun R. Naik (University of Wisconsin-Milwaukee) • Claus Germann Petersen (Germann Instruments) • Jan P. Skalny (Materials Service Life) • R. N. Swamy (University of Sheffield)

LOCAL ORGANIZING COMMITTEE

• Leticia M. Torres Guerra (UANL) • Konstantin Sobolev (UANL) • Oscar Moreira-Flores (UANL) • Alejandro Duran Herrera (UANL) • Pedro Valdez Tamez (UANL) • Cesar Juarez Alvarado (UANL) • Gerardo Fajardo (UANL) • Jesús Montemayor Villela (UANL)


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1st INTERNATIONAL CONFERENCE ON ADVANCED CONSTRUCTION

MATERIALS In the tradition of earlier Symposiums on Hybridized Materials with Super-Functions (HMSF), the Universidad Autónoma de Nuevo León (UANL) and Nagaoka University of Technology organize the 3rd Japan-Mexico HMSF symposium from 3rd to 6th of December 2006. In conjunction with this symposium, the 1st International Conference on Advanced Construction Materials (ICACM) is host by the Civil Engineering Faculty of UANL, the Academic Group on Concrete Technology and ACI Northeast Mexico Chapter. The conference will continue the tradition established by Raymundo Rivera’s international conferences and symposiums on concrete technology held at Monterrey, Mexico since 1971. ICACM will cover a broad range of the subjects related to a design of advanced construction materials with focus on high-strength and high-performance materials, durability, and corrosion protection, materials with smart properties, application of chemical admixtures and fibers, eco-materials and waste utilization, application of nanomaterials. This bilingual (English and Spanish) conference will provide a platform for enhancing intellectual interactions among the researchers from academic institutions and industry; therefore it will be relevant to any person from academia, research establishments or industry with interest on latest developments in construction materials. Topics of interest:

• High-strength and high-performance materials • Application of nano-materials • Smart materials • Chemical admixtures • Fiber-reinforced composites • Durability and corrosion • Sustainability and eco-materials


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SPONSORS

Universidad Autónoma de Nuevo León http://www.uanl.mx

Nagaoka University of Technology http://www.nagaokaut.ac.jp

Facultad de Ingeniería Civil, UANL http://www.fic.uanl.mx

Facultad de Ingeniería Mecánica y Eléctrica http://www.fime.uanl.mx

Universidad de Guanajuato http://www.ugto.mx

Universidad Michoacana San Nicolás Hidalgo http://www.umich.mx

CONACYT http://www.conacyt.mx

AMERICAN CONCRETE INSTITUTE http://www.concrete.org

CEMEX México http://www.cemexmexico.com

ANALITEK, S.A. de C.V. http://www.analitek.com

Bruker Mexicana http://www.bruker.com.mx

JEOL de México, S.A. de C.V. http://www.jeol.com.mx


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ADVANCED AND SMART CEMENT-BASED MATERIALS

DESIGN OF WATER-RESISTANT GYPSUM BINDERS

Jean Pera, Caroline Angulski da Luz and Jean Ambroise

Unité de Recherche en Génie Civil Institut National des Sciences Appliquées de Lyon

Domaine Scientifique de la Doua, 12, Avenue des Arts Bâtiment Joseph Tuset, 69621 Villeurbanne Cedex, FRANCE

E-mail: [email protected] Gypsum is a cheap binder but its utilization remains limited due to its bad water resistance. The solutions usually proposed to improve this water resistance consist in adding water repelling agents like organo-polysiloxanes to the mixing water. This paper shows that another solution is to mix calcium sulfoaluminate clinker and gypsum. When hydrating, such mixture becomes water-resistant and gypsum is converted into a hydraulic binder. Therefore, it is possible to develop low cost housing materials, mainly based on gypsum. The experimental results show that the quantity of calcium sulfoaluminate clinker necessary to stabilize gypsum is in the range of 20 to 30%. In such case, resistance to wetting-drying cycles is very good. Building materials like concrete blocks, renders, and screeds were developed and behaved very well under natural weathering for more than 3 years. This can be a solution to valorize large amounts of gypsum by-products and develop low cost housing materials. Keywords: building materials, calcium sulfoaluminate cement, ettringite, hydration, phosphogypsum, water-resistance

AUTOCLAVED AERATED CONCRETE: PRACTICAL APPLICATIONS FOR AN INNOVATIVE

CONSTRUCTION MATERIAL

Richard E. Klingner Civil Engineering, The University of Texas at Austin, USA

E-mail: [email protected]

Autoclaved aerated concrete (AAC) is a lightweight, concrete-like material with many useful structural and architectural characteristics. It is strong enough for structural applications; it weighs about as much as wood; and its internal structure of closed voids gives it very favorable thermal and acoustical behavior. It can be shaped with hand tools, and can be made with a high percentage of recycled materials. These qualities combine to make it very intriguing for architectural and structural design. In this article,


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the basic physical behavior of AAC is described; current applications are discussed; and structural engineers are invited to explore different possibilities for its use.

Keywords: autoclaved, aerated, concrete, AAC, lightweight, structural, thermal and acoustical behavior

FIBER OPTIC SENSING OF THE INTERNAL RELATIVE

HUMIDITY FOR IMPROVED CONCRETE PERFORMANCE

Richard A. Livingston*, Jeremiah Slade**, John Player**, Susan B. Kristoff***, Stephen J. Kokkins*** and Richard Lusignea****

*Office of Infrastructure R&D, Federal Highway Administration, USA **Infoscitex Inc., USA

***Foster-Miller Inc., USA ****Fulcrum Solutions Inc., USA


The internal relative humidity (RH) of concrete is an important variable for several reasons. It is an indicator of the progress of the main hydration reaction that determines the concrete macroscopic properties. It can also provide warning of various conditions that can affect the performance of the concrete including self-desiccation, alkali-silica reaction or delayed ettringite formation. Despite its importance, internal RH has not been explicitly measured on an operational basis, because of the difficulties of working with conventional electronic sensors. Sensors based on fiber optics offer several advantages including ruggedness, immunity to electromagnetic interference, compactness and the capability of multiplexing a large number of sensors on a single fiber. A commercial fiber optic sensor for internal RH is being developed under a Phase II Small Business Innovative Research (SBIR) grant from the U.S. Federal Highway Administration. This is based on a fiber Bragg grating strain sensor combined with a hygroscopic polymer which swells in response to changes in RH. A second Bragg grating is included in the sensor for temperature compensation. Tradeoffs being investigated include sensitivity, response time, size and protection against the high pH pore water solution. Field testing of the sensors will include installation in a bridge on Interstate I-10 in Las Cruces, New Mexico.

Keywords: internal relative humidity, Bragg grating, fiber optics, hygroscopic


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DRYING SHRINKAGE IN RECYCLED-AGGREGATE CONCRETE

G. Moriconi and V. Corinaldesi

Department of Materials and Environment Engineering and Physics Marche Polytechnical University

via Brecce Bianche, 60131, Ancona, Italy E-mail: [email protected], [email protected]

Recycled-aggregate concrete, in particular when containing high volume fly ash, is an example of construction material whereby sustainable construction development is feasible with satisfactory performance, in terms of both safety and serviceability of structures, at lower costs and with environmental advantages over ordinary concrete. However, recycled-aggregate concrete is well-known for its higher tendency to shrink with respect to concrete prepared with ordinary aggregate. It could be a problem even if, due to its higher deformability, the tensile stress induced on it by shrinkage strain is certainly lower. Trying to make recycled-aggregate concrete less sensitive to shrinkage phenomena, different concrete mixtures were prepared with the same water to cement ratio by varying the kind of aggregate, either an ordinary crushed aggregate or a recycled aggregate coming from a recycling plant in which rubble from building demolition are suitably treated. Moreover, two kinds of superplasticizer were tested: the first was based on polycarboxylate polymers, the second was based again on polycarboxylate polymers but incorporating a shrinkage reducing group. Both superplasticizing and multi-function admixtures were added at a dosage of 1% and 2% by weight of cement respectively. Compression tests were carried out at different curing time as well as free-drying shrinkage was measured up to 180 days after casting. Encouraging results were obtained in terms of recycled-aggregate concrete shrinkage reduction. Keywords: recycled, aggregate, concrete, fly ash, superplasticizer, shrinkage reducing, free-drying shrinkage COMPUTATIONAL DURABILITY MECHANICS OF CEMENT

COMPOSITES

John Bolander Department of Civil and Environmental Engineering

University of California, Davis One Shields ave. Davis, CA 95616, USA

E-mail: [email protected] Model-based simulation can be viewed as an effective tool for concrete materials development and structural design, particularly when the spatial and/or temporal scales of the problem extend beyond the practical limits of


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physical testing. Model-based simulation provides a virtual laboratory for studying the relationships between material structure and the various thermal, chemical, and mechanical processes apparent at those different scales. The bridging of spatial and temporal scales is especially important when studying the life-cycle performance of structural components and systems subjected to severe environments. The presentation concerns the development of a general framework for simulating the performance of concrete materials under environmental loadings. The framework is based on the use of three-dimensional, irregular lattice models of elasticity, moisture movement, and damage in concrete materials, along with the interactions of various types of reinforcement. The sequence of model construction, computer solution, and results interpretation is streamlined to enable model revision and re-analysis within short periods of time. Such an approach facilitates material and structural design within large variable spaces, which may be affected by uncertainty in the design parameters. Keywords: model simulation, concrete, virtual laboratory, structure, life-cycle performance

INNOVATIONS IN CONCRETE MATERIALS AND STRUCTURES: PAST, PRESENT AND FUTURE

Paulo Helene

Escola Politécnica da Universidade de São Paulo Instituto Brasileiro do Concreto IBRACON, São Paulo, Brazil

E-mail: [email protected] The goal of that article is to show that the concrete technology as the last but one the most significance construction contribution to human history and evolution. Also is to present the idea that the greats changes in construction practices and design of structures during last 50 centuries must be paid to discover of new materials. New materials are the guide and way for great changes and evolution. United States and Canada, two major economies and developed societies, through “ACBM” in USA and “Béton Canada”, have been considered concrete structures as one of the most significance science and technology to contribute for the quality of life for the citizens and defend the national industry. They understand that the knowledge in concrete have the mission to position the national construction industry at the leading edge of concrete technology in order to enhance its competitiveness. Consequently the National Science Foundation in both nations include that knowledge as strategic for the intelligence of country as side as knowledge in natural resources and environment; health, human development and biotechnology; advanced technologies and manufacturing. The good consequence was a large concrete development in the last 15 years. Scientific America, have published 232 documents about research & developments in concrete in the last 10 years. Science News on


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line have been published innovations in concrete technology frequently and also Popular Science Magazine recognized “conductive concrete” as one of 1996's most innovative ideas in product development in the world. During last year the National Building Museum, in Washington, USA, has presented the “New Architecture in Concrete” called “liquid stone” with 30 news innovations in concrete technology. When the Egyptian society recognized the physician Imhotep as the first Architect in world, was because he proposed, designed and builds the first Pyramid using blocs of rocks. The Egyptians “architects” discovered the methods to use properly the rocks to built, instead clay and wood very well-known at this time. In that manner they could build the most impressive and durable engineered structures representing the power and development of Egyptian civilization, the pyramids. After that Greeks, Persians, Romans and the great architects in Medium age have used the blocs of rocks to built durable and significance structures. Colony and Notre Dame Cathedral perhaps could be the most developed structures using rocks and finding 50m as maximum span. Consequently wood, clay and rocks was determined the way of structures: arches to win spans, structural masonries walls and limited high buildings (4 levels). The great change occurred in XIX Century when the new steel industry allow to Gustave Eiffel design and built her Eiffel Tower, in 1889, with 312m high, surpassing the highest structure in world until that time, the great Pyramid of Queops with 146m high, in Egypt after 44 centuries (4400 years!). When the first Standard for Design Concrete Structures in the world, published in Switzerland, in 1903, the steel construction was much more developed and in 1931 the American engineers astonish the world with Empire State Building, with 383m high. No more structural walls, no more arches to win spans. The construction design had changed for columns, beams and slabs, and the walls were only for hedge off. But concrete have developed so much during last century and now is the most important construction in world, surpassing steel. Many companies have adopted and optimized new technologies based on expertise developed through collaborative efforts with researches in developed centers like ACBM, Béton Canada, Monterrey Concrete group, and innumerable others in the world. Concrete now, much more than others construction materials, response to a real world need. Much of the way we live depends on concrete. Our houses, roads, cities and underground support systems are all structured from this. We must keep that in mind and take the advantage of this spectacular and vital construction material, improving his performance and using it with environmental and sustainability point of view. Treat of a material in transformation, in evolution which can improve much more the construction technologies options in the future. Keywords: construction materials, concrete structures, construction history, construction innovation


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DEVELOPMENT OF A HIGH-DENSITY, HIGH-STRENGTH, CEMENTITIOUS GROUT USING NANO-PARTICLES

Brian H. Green

Concrete and Materials Branch, Geotechnical and Structures Laboratory US Army Engineer Research and Development Center 3909 Halls Ferry Road, Vicksburg, MS, USA 39180-6199

E-mail: [email protected] This paper describes the development of a high-strength, high-density cementitious grout mixture. This portland cement-based grout incorporated silica nano-particles or nano-silica in the form of an ultra-fine amorphous colloidal silica admixture along with hematite fine aggregate, silica fine aggregate, silica fume, water, and other chemical admixtures to match as closely as possible the given in-situ high-strength rock properties. The grout was then placed in the field with over 200 individual batches to fill the annular space surrounding instrumentation packages previously placed in drilled boreholes. The resultant mechanical properties of the field-placed rock-matching grout (RMG) included unconfined compressive strengths of 91.2 MPa, hardened densities of 2680 kg/m3, and ultrasonic pulse velocities of 4.40 km/sec. The nano-silica used in this field work was a key component in the successful completion of this project.

Keywords: high-strength, high-density cementitious grout, cement, nano-particles, nano-silica, ultrasonic pulse velocity

CALCIUM SULFOALUMINATE CEMENTS: OPPORTUNITIES

AND CHALLENGES AS AN ADVANCED MATERIAL FOR THE CONSTRUCTION INDUSTRY

Waltter Lopez-Gonzalez*, Patricia Lopez-Armendariz** and

Carlos Castillo-Linton** *Cemex-USA Technical Center, E-mail: [email protected]

**Cemex-Mexico, E-mail: [email protected], [email protected]

The high cost of conventional fuels, has been driven the cement industry to experiment with alternative fuels and raw materials, some of them with very high sulfur content. Since the last decade, the cement industry has been innovating its processes and products to handle higher concentrations of sulfur and minimizing process issues related with the use of high sulfur concentrations in the kilns, like buildups and plugs in the preheater [1]. One approach has been to develop a new type of clinker capable to fix sulfur in a hydraulic active mineral phase as calcium sulfoaluminate (C4A3S). Besides the value of fixing large quantities of sulfur in the clinker, the sulfoaluminate phase brings new properties to the cement, such as: higher


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early strength development [2], and shorter setting times than ordinary Portland cements, that has been used with success for fast repairs of concrete in terms of hours, and also, a high resistance to sulfate attack by eliminating the risk of having tricalcium aluminate (C3A) as part the cement composition [3]. In the other hand, one of the current challenges for using the sulfoaluminate cements more extensively is the difficulty to use traditional concrete technology to pour concrete friendly. The innovation on this arena would trigger the use of sulfoaluminate – another new fast-setting cements and binders – in the construction industry of the XXI century. Keywords: sulfoaluminate, cement, sulfur, high-strength, short-setting, sulfate-attack [1] US Patent number 6,599,123: Method to produce cement clinker using high sulfur content fuel. Homero Ramirez-Tobias, Alberto Lazaro-Franco, Juan Carlos Martinez-Burckhardt and Waltter Lopez-Gonzalez. [2] US Patent number 6,149,724: Hydraulic cement with accelerated high strength development. Ramon Poo-Ulibarri, Waltter Lopez-Gonzalez and Jose Sacramento Villafaňa-Torres. [3] US Patent number 20050126444: Clinker and white portland cement with high sulfur content derived from a high sulfur content pet-coke used as fuel. Waltter Lopez-Gonzalez, Carlos Enrique Castillo-Linton and Graciela Eguia-Marquez.

EFFECT OF CRACK CONTROL ON DURABILITY

Claudia P. Ostertag Civil Engineering Department, University of California

721 Davis Hall, Berkeley, CA. 94720-1710, USA E-mail: [email protected]

The talk will focus on a novel micro and macro-mechanical approach to mitigate damage associated with corrosion and alkali silica reaction. The approach utilizes a hybrid fiber reinforced concrete (HyFRC) composite that consists of both micro and macrofibers to control cracking from the micro-to the macrolevel. The microfibers control microcracking at onset in close vicinity to the reaction sites and synergy between the micro-and macrofibers provides deflection hardening which delays macrocrack formation up to more than three times the load levels compared to plain concrete specimens. Designed initially as a mechanical approach for retarding macrocrack formation it proved, based on preliminary results, to have the potential of producing very significant gains in concrete durability by delaying damage initiation and minimizing damage propagation. Preliminary results on mitigating damage due to expansive deterioration processes such as corrosion and alkali silica reaction through crack control will be presented. Electrochemical measurements reveal that HyFRC composites exhibit far lower corrosion rates compared to control specimens after being exposed to a corrosive environment. Deterioration reduction through crack control from the micro-to the macrolevel not only resisted


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crack propagation and expansion due to alkali silica reaction, but also reduced the reaction rate and reactivity of the reactive aggregate as will be discussed. Keywords: corrosion, alkali silica reaction, micro-and macrofibers, concrete, HyFRC, composite, crack propagation, expansion

EFFECT OF DIFFERENT TYPES OF AGGREGATES ON AUTOGENOUS AND DRYING SHRINKAGE OF CONCRETE

Tarun R. Naik, Rudolph N. Kraus, and Yoon-moon Chun

Center for By-Products Utilization, Department of Civil Engineering and Mechanics, University of Wisconsin-Milwaukee

P. O. Box 784, Milwaukee, WI 53201, USA E-mail: [email protected]

This paper summarizes recent research completed by the UWM Center for By-Products Utilization on the effects of different types of coarse aggregate in concrete on the shrinkage properties of concrete. Three types of coarse aggregate were used in the concrete mixtures: crushed quartzite stone, semi-crushed river gravel, and crushed dolomitic limestone. Concrete mixtures were made with and without a shrinkage-reducing admixture. Both autogenous shrinkage and drying shrinkage were evaluated for each concrete mixture. Concrete mixtures made with semi-crushed river gravel and crushed dolomite showed a significantly lower autogenous shrinkage than the concrete made with crushed quartzite. Use of dolomitic limestone appears to be useful in reducing early-age autogenous shrinkage and drying shrinkage of concrete compared with using river gravel or quartzite as coarse aggregate. Use of crushed dolomitic limestone in concrete led to the lowest early-age drying shrinkage, followed by semi-crushed river gravel, and crushed quartzite stone. However, at later ages, the drying shrinkage became similar for most aggregates. River gravel often had the highest drying shrinkage at later ages. As a whole, the effect of the source of coarse aggregate on drying shrinkage appears to be noticeable but small. Keywords: aggregate, concrete, autogenous, shrinkage, quartzite, river gravel, dolomitic limestone, drying


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EFFECT OF MIXTURE PROPORTIONS ON COEFFICIENT OF THERMAL EXPANSION OF CONCRETE

Tarun R. Naik, Yoon-moon Chun, and Rudolph N. Kraus

Center for By-Products Utilization, Department of Civil Engineering and Mechanics, University of Wisconsin-Milwaukee

P. O. Box 784, Milwaukee, WI 53201, USA E-mail: [email protected]

This paper summarizes recent research conducted by the UWM Center for By-Products Utilization on the coefficient of thermal expansion (CTE) of concrete. A standard concrete mixture specified by the Wisconsin Department of Transportation was used as the basis for all other concrete mixtures. Coarse aggregates obtained from 15 different sources were investigated. They were glacial gravel from six sources, dolomite from five sources, quartzite, granite, diabase, and basalt. From the types of coarse aggregates tested, the concrete made with quartzite had the highest CTE, 12.2 microstrain/°C (6.8 microstrain/°F). The concrete mixtures made with diabase, basalt, and granite showed the lowest CTE, ranging from 9.3 to 9.5 microstrain/°C (5.2 to 5.3 microstrain/°F). The CTE of concrete made with glacial gravel from the six sources ranged from 9.7 to 10.7 microstrain/°C (5.4 to 5.9 microstrain/°F). The CTE of concrete mixtures made with dolomite from the five sources was approximately the same, ranging from 10.4 to 10.8 microstrain/°C (5.8 to 6.0 microstrain/°F).

Keywords: thermal expansion, concrete, aggregates, quartzite, granite, diabase, dolomite, basalt

GEOPOLYMERS: PAST, PRESENT AND THE FUTURE

Dan S Perera

ANSTO, Sydney, Australia E-mail: [email protected]

The durability of ancient Roman cements led to the study of these in the Ukraine in the 1950s and development of slag-alkaline cements. Buildings constructed using these cements in the 1960s are still in existence. They were termed geopolymers by Davidovits in the late 1970s. They are made by mixing reactive aluminosilicate precursors with concentrated alkali silicate solutions to make a stiff paste, which subsequently polymerises on curing at 20-90oC to form a solid. Their physical behaviour is similar to that of ordinary Portland cement (OPC) and they have been considered as a possible improvement on OPC in many aspects. Geopolymer concrete gave the same or better values than OPC concrete under the same tests recommended for the latter. It is estimated that to produce 1 tonne of OPC, ~ 1 tonne of CO2 is produced,


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whereas only ~ 0.14 tonne of CO2 is produced for the production of the alkali precursor required for geopolymers. This is considered as an important driving force to develop geopolymers to replace some of the applications where OPC is used. The energy required to produce geopolymers is estimated at about 1/3rd that required to produce OPC. The understanding of the chemistry to develop current and future applications such as hazardous and radioactive waste immobilisation, biomaterials, joining of materials, glasses and glass ceramics will be discussed. Key aspects of geopolymer research undertaken in understanding the structure, kinetics, mechanical properties, microstructure and curing will be discussed. Keywords: concrete, environmental, nanoporous, low-energy.

EFFECT OF ADDITION OF NANO-SIO2 ON THE SETTING TIME OF CEMENT HYDRATION

Luciano Senff*, Wellington L. Repette*, Phillipe Gleize*, Marilena V.

Folgueras**, Dachamir Hotza* *Universidade Federal de Santa Catarina – UFSC, Florianópolis, SC, Brazil **Universidade do Estado de Santa Catarina - UDESC, Joinville, SC, Brazil

E-mail: [email protected] In the last years several researchers have studied the use the nanoparticles in cement materials. In general, when the nanoparticles are added in mortar or concrete the properties have improved compared to the conventional materials. The high reactivity of the nanoparticles is the main reason to be considered. Immediately after mixing cement with water, the formation of the concentrated suspension of ions occurs, which progressively forms a rigid structure. Mineral additives can modify the reaction kinetics. In this paper, the effect of nanosilica (nano-SiO2) addition was studied in relation to the setting time of the cement paste. Samples were produced with different amounts from nano-SiO2 in the cement paste (0, 1, 2 and 5% nano-SiO2). The standard consistence paste was maintened by adding different amounts of superplasticizer. CP V ARI - RS cement was used and the setting times were measured with the Vicat needle. In general, it was observed that the addition of nano-SiO2 in the Portland cement paste influenced the whole process of setting. Keywords: nanosilica, portland cement, setting time, Vicat needle.


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FILTRATION RATE VS. COMPRESSIVE STRENGTH IN PERVIOUS CONCRETE

José Juan Flores, Bernardo Martínez, Roberto Uribe, Rosa Elba Rodríguez,

Homero Montaño Centro de Tecnología Cemento y Concreto, CEMEX Concretos


There is an increasing interest in the use of pervious concrete, mainly because it represents a technological option for sustainable development; as it is well known, in addition to its filtration properties, this kind of concrete has the capability to reduce the noise generated by the vehicles circulating over these types of surfaces. Its main function consists in the water permeation, in order to destine it to diverse uses according to the particular needs of each project. Its filtering capability can be maximized using integral systems designed in accordance to local conditions of pluvial precipitation, subsoil permeability, as well as other environmental factors. In the present project, a characterization of different mixture designs based on this technology is made, using a proposed test which measures the filtering capabilities and analyzes its behavior, in relation to the mechanical properties of compressive and flexural strengths that are achieved under different mixture designs. Furthermore, the tests analyze the individual and accumulated influence of different factors that take part in the filterable concrete design, such as cement consumption, the addition of different percentages of sand, or the use of additives that modify the fresh-state properties, in order to obtain an appropriate range of designs for different service and exposure conditions. Keywords: pervious concrete, filtration, mixture design. DEVELOPMENT OF AN OPTIC FIBER SENSOR TO DETECT

THE FORMATION OF FISSURES IN CONCRETE STRUCTURES

K. Rodríguez Carmona, J. M. Lugo Cuevas, A. Márquez Lucero

Centro de Investigación en Materiales Avanzados, S.C. (CIMAV), Miguel de Cervantes 120, Complejo industrial Chihuhua. Chihuahua, México CP 31109

E-mail: [email protected], [email protected] When a large fissure is produced in a concrete structures often it is very late to be required because the fissures han been spread. Due to this problem in the present work, we develop a sensor based on optical fiber, to detect fissures from their origin. The aim of this sensor is monitoring the formation of fissures, at their initial stages propagation, in the order to avoid the failure of a structure. The functionality of this sensor was demonstrated since it was achieved to detect the formation of fissures early, in laboratory


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samples. This distributed sensor employs a single optical fiber, with out another arrangement. This sensor can be used also to obtain some information about deformation of the structures, previous to a calibration. Keywords: monitoring, fissure, optical fiber, concrete, structures

EFFECT OF HIGH ENERGY MILLING (HEM) AND ADDITION

OF FLUX DURING PREPARATION OF CLINKER FOR ORDINARY PORTLAND CEMENT (OPC)

O. Chimal Valencia*, M. S. Corral García*, A. de Ita de la Torre** y

S. Díaz de la Torre*. *Centro de Investigación e Innovación Tecnológica (CIITEC-IPN)

Cerrada de Cecati S/N. Colonia Santa Catarina. Delegación Azcapotzalco. C. P. 02250. México, D. F., México

**Universidad Autónoma Metropolitana – Azcapotzalco División de Ciencias Básicas e Ingeniería

av. San Pablo No. 180, Col. Reynosa Tamaulipas, Delegación Azcapotzalco. C. P. 02200. México D. F., México

E-mail: [email protected] The theoretical energy consumption during formation of industrial clinker at 1450°C is about 1605 J/g of clinker [1]. Nowadays, the prime aim of energy saving regulations is the reduction of CO2 emission so as to prevent global warming, which causes environmental problems on the planet [2]. The reduction of costs via energy saving could be the first purpose instead. In this work, simultaneous influence of particle size reduction of raw material and the effect of a flux rich in sodium, aluminium and flour addition during the preparation of clinker for Ordinary Portland Cement (OPC) were investigated. Clinker prepared under our conditions was characterized, the results shown that is possible to decrease the reaction temperature below 1450°C. Burnability of raw material was related with free lime quantity. Phases C3S, C2S, C3A and C4AF were analyzed by Rietveld method. OPC Cement type was prepared using clinker obtained at low temperature and its compressive strength was compared versus commercial OPC. Keywords: high energy milling, flux, clinker, cement [1] My. Y. Bernarchid, A. Diouri, A. Boukhari, J. Aride, J. Rogez and R. Castanet.

Cement and Concrete Research 34 (2004) 1873. [2] Y. Mizuta. Management of Environmental Quality; An International Journal.

Vol. 14 No.2. 2003.


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STRUCTURE, MICROSTRUCTURE AND PROPERTIES OF ORGANICALLY MODIFIED CEMENT

Francisco J. Jiménez-Alvarez, Lucía Téllez-Jurado, Heberto Balmori-Ramírez

Depto. Ing. en Metalurgia y Materiales, ESIQIE-IPN, Zacatenco, 07738, México D. F., México


The materials based on Portland cement display some disadvantages such as slowed down hardening, shrinking, low chemical resistance, low resistance to the tension, etc. In order to diminish these disadvantages, in the present work we focused in the introduction of organic component into the Portland cement matrix in order to improve its mechanical properties. The organic component (OC) was obtained from High Density polyethylene (HDPE) by a depolymerization reaction and it was characterized by means of GC-MS and FT-IR. The OC and hydration water was added at the same moment into the cement matrix. The weight ratio of cement/(water hydration + OC) was constant and OC amount (% weight) were varied as follows: 0, 0.74, 1.47, 2.21 and 2.94. The final materials (cement-modified) were characterized by means of XDR, FT-IR, SEM and OM. The results show that the compression strength, and Young´s module were improved and the porosity and the morphology of modified cement were dependent on the OC amount used. Keywords: cement, compressive strength, depolymerization, polyethylene.

THE EFFECT OF COMPLEX ADMIXTURES ON PROPERTIES

OF HIGH-PERFORMANCE CEMENT

R. Hermosillo, A. Alvarez-Méndez, and K. Sobolev Facultad de Ingenieria Civil, Universidad Autonoma de Nuevo Leon

AP #17 Cd. Universitaria, San Nicolas de los Garza, N.L. Mexico 66450 E-mail: [email protected]

Chemical admixtures can be used to modify the cement grinding process and induce changes in the structure of cement minerals due to mechano-chemical activation. A reactive silica-based complex admixture was developed for the modification of cement grinding. This paper examines the effect of grinding on the strength of modified cement produced with different types of complex admixture. According to the test results, mortars based on the modified cement possess a 28-day compressive strength of 106-115 MPa, a 25-35% increase over the reference. At the same time, the fluidity of such mortars increases by 18-90%. It is proposed that developed cements can find their application in high-performance concrete. Keywords: chemical admixtures, reactive silica, cement, grinding, mechano-chemical activation, strength, high-performance cement.


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MECHANICAL BEHAVIOR AND CHARACTERIZATION OF MORTARS BASED ON PORTLAND CEMENT PROCESSED

BY HIGH-ENERGY MILLING

J.C. Arteaga A., O. A. Chimal V., S. Díaz de la T. Centro de investigación e Innovación Tecnológica (CIITEC)

Instituto Politécnico Nacional CECATI s/n Col. Santa Catarina, Azcapotzalco, México D.F., 02250, México

E-mail: [email protected], [email protected], [email protected]

In agreement with literature there are different techniques that allow increase values of compressive strength in mortars or concretes fabricated using Ordinary Portland Cement (OPC). One of these techniques is the addition of ultrafine pozzolanic materials [1, 2]; another technique consists in the particle size reduction of cement until some microns [3]. In this work, High Energy Milling (HEM) process is used to reduce particle size of CPC 30R Portland cement. After HEM process average of Particle Size Distribution (PSD) is about 5 µm in milled cement. Mortars prepared using this cement showed compressive strength values over 75 MPa. Laboratory studies to determine HEM effect over crystallographic structure and mechanical behavior of mortars include quantification and identification of main crystallographic phases through Rietveld method, heat of hydration, setting time, flow, workability and compressive strength under normal and cryogenic conditions to determine material behavior in freeze environment. Keywords: portland cement, high energy milling, ultrafine powders, compressive strength [1] S. L. Sarkara, J. Wheelerb. Important properties of an ultrafine cement–Part I. Cem. and Conc. Res. 31 (2001) 119 – 123. [2] Niu. Q. Feng, Yang. J. Effect of superfine slag powder on cement properties. Cem. and Conc. Res. 32 (2002) 615–621. [3] De la Garza. G. H. Cemento Pórtland Ultrafino de alta resistencia. Tesis de Maestría. CIMAV, México. (2003).

EFFECT OF NANO-SIO2 ON PROPERTIES OF CEMENT

BASED MATERIALS

I. Flores, L.L. Garza-Tovar, L.M. Torres-Martínez, and K. Sobolev Facultad de Ingenieria Civil, Universidad Autonoma de Nuevo Leon

AP #17 Cd Universitaria, San Nicolas de los Garza, N.L., México 66450 E-mail: [email protected]

Nanotechnology has changed our vision, expectations and abilities to control the material world. The developments in nano-science will have a great impact on the field of construction materials. Portland cement, one of the


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largest commodities consumed by mankind, is obviously the product with great, but not completely explored potential. Better understanding and engineering of complex structure of cement based materials at the nano-level will apparently result in a new generation of concrete, stronger and more durable, with desired stress-strain behavior and possibly possessing the range of newly introduced “smart” properties. The research work examined the workability and mechanical properties of high-performance superplasticized mortars with nano-SiO2. Experimental results demonstrated an increase in compressive strength of mortars containing nano-particles. It was found that at constant W/C the application of nano-SiO2 admixture provided 15-20% increase in the compressive strength. The mortars with compressive strength of up to 144.8 MPa were obtained using this approach. Keywords: nano-SiO2, superplasticizer, compressive strength, mortar, high-performance, cement


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FIBER-REINFORCED CONCRETE

ENGINEERED CEMENTITIOUS COMPOSITES

Victor C. Li Department of Civil and Environmental Engineering, The University of

Michigan, Ann Arbor, USA E-mail: [email protected]

This paper overviews Engineered Cementitious Composites (ECC) as an emerging construction material. Emphasis is placed on the accumulated knowledge on durability, safety, and sustainability of reinforced ECC (R/ECC) structures, recognizing that the concrete of the future must meet these characteristics. In light of recent and future full-scale field applications of ECC, the limited studies on long-term performance of ECC are also summarized. Keywords: composite, fiber, ductility, durability, sustainability, safety, design, infrastructure.

CASOS PRÁCTICOS EN MÉXICO DE ESTRUCTURAS DE CONCRETO REFORZADAS CON COMPUESTOS FRP

H. Cuadros Abad, H. Orozco Recillas

Sika Mexicana S.A. de C.V., km 8.5 Carret. Libre a Celaya, Corregidora, Querétaro


El presente artículo describe brevemente algunos casos prácticos en México, en donde se utilizó la tecnología de los compuestos políméricos reforzados con fibras de carbono (CFRP), externamente adheridos a los elementos de concreto, para restituir su capacidad original o para ser incrementada. Palabras clave: compuestos políméricos reforzados, fibras de carbono, CFRP, concreto


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RESISTENCIA A LA COMPRESIÓN DE CONCRETO REFORZADO CON FIBRAS

Gonzalo Martínez-Barrera, Mónica Olín-Ramírez, Gerardo Mañón-Barroso

Laboratorio de Investigación y Desarrollo de Materiales Avanzados (LIDMA), Facultad de Química, Universidad Autónoma del Estado de

México, Toluca México, CP 50000 MEXICO E-mail: [email protected]

La búsqueda de novedosos materiales de construcción, así como el mejoramiento de los ya existentes, han sido determinantes para el desarrollo tecnológico de los países desarrollados. Los materiales fibroreforzados han satisfecho requerimientos económicos, científicos y tecnológicos, en diversas aplicaciones, en donde han sido requeridos. Uno de los factores predominantes es la selección adecuada de los componentes que se utilicen para su elaboración, primordialmente el de las fibras sintéticas, de las cuales se deben conocer sus propiedades físicas y químicas. Tradicionalmente se han modificado las fibras sintéticas mediante tratamiento térmico, ataque químico, entre otras. Dichas modificaciones requieren de preparar el material o bien tener los disolventes adecuados; a este respecto existe la posibilidad de la modificación estructural de las fibras mediante energía ionizante: radiación gamma. En el presente trabajo, se estudian los efectos de dicha radiación en concretos elaborados con mármol, arena sílice y fibras poliméricas; se varía la dosis de radiación hasta alcanzar 150 kGy y se evalúa la propiedad mecánica de compresión de los concretos, así como la caracterización estructural de las fibras mediante espectroscopia Raman. Palabras clave: resistencia a la compresión, concreto, fibras, radiación gamma


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SUSTAINABILITY, ECO-MATERIALS, RECYCLING AND WASTE UTILIZATION

HIGH VOLUME FLY ASH CONCRETE: FIELD EXPERIENCE

Mohan Malhotra CANMET, Canada

E-mail: [email protected] As a major part of the world economy, the concrete industry must play an active role in reducing the rate of greenhouse gas emissions, which is essential for sustainable development. Because there are few new technologies that can reduce CO2 emissions from the manufacturing of portland cement, the answer lies in minimizing the output of cement clinker. The discussion in this article advocates the use of fly ash, other supplementary cementitious materials, and high-range water-reducing admixtures to help reduce cement production. Keywords: concrete, greenhouse gas emissions, sustainable development, cement, fly ash, supplementary cementitious materials, high-range water-reducing admixture

ROLE OF A MEXICAN ASTM CLASS F FLY ASH IN ENHANCING DURABILITY OF CONCRETE

Rosa Elba Rodríguez Camacho, Bernardo Martínez Sánchez, José Juan Flores

Martínez, Roberto Uribe Afif, Homero Jesús Montaño Román Centro de Tecnología Cemento y Concreto, CEMEX Concretos

E-mail: [email protected] The purpose of this study was to examine the effect of a Class fly ash on mechanical and durability properties of concrete. The fly ash used in this study, from a Mexican source, was characterized by chemical and mineralogical analysis, and by its pozzolanic activity. Concrete mixtures were prepared with 20, 25 and 30 % fly ash by mass of total cementitious material. Concrete specimens were cast and tested to determine the durability of fly ash concrete; the tests used included water, rapid chloride permeability tests (RCPT), migration test, acid resistance and abrasion resistance tests. Also the compressive strength was determined. Mortar specimens were used to evaluate sulfate resistance and alkali-silica reaction. The results of this study confirmed that the Mexican Class F fly ash was suitable in improving the durability characteristics of concrete when used as 25% or higher dosage of cement replacement. Keywords: fly ash, concrete, pozzolanic activity, cementitious material.


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BLEEDING RATE AND CAPACITY OF CONCRETE

R. Sri Ravindrarajah Centre for Built Infrastructure Research, University of Technology, Sydney,

Australia E-mail: [email protected]

Pre-hardening cracking of concrete is a common occurrence in concrete and these secondary cracks reduces the durability of the concrete structures. Cracks developed in concrete while it is in the plastic state between 3 to 7 hours after concrete placing is known as plastic settlement and plastic shrinkage cracks. These cracks are closely related to the bleeding process in concrete, which is a natural time-dependent process in a freshly placed concrete. In this process, a portion of the mixing water together with very fine materials, both cementitious and fine fractions of the sand, finds its way to the concrete surface. The bleeding rate in concrete slows down with the time after placing. However, the bleeding process may continue to occur for a period up to 2 hours. When the concrete is placed by pumping it is become necessary to have control over the bleeding capacity to achieve stable concrete mixes under pressure. In addition, pre-hardening concrete cracking is a major concern in hot weather concreting around the world. Both the bleeding rate and bleeding capacity of concrete are affected by the amount of very fine materials in concrete as well as the mix compositions. This paper reports the results of an extensive study on the effects of binder materials and the mix compositions on the bleeding rate and the bleeding capacity of fresh concrete. The parameters used in this study were the water content, superplasticiser dosage, granulated blast-furnace slag as fine aggregate replacement, fly ash for cement replacement, and fly ash as an addition material. The results indicated a direct correlation between the bleeding capacity of the concrete and the initial bleeding rate. The empirical expression is presented is useful to predict the bleeding capacity based on the initial bleeding rate. Keywords: bleeding, fly ash, blast-furnace slag, superplasticiser, water content, fine aggregate


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STRUCTURAL ELEMENTS COMPOSED OF WOOD AND CONCRETE

Walter von Roth*

Maria de los Angeles Rechy** * Faculty of Civil Engineering, Technical University Neubrandenburg,

Germany ** Faculty of Forest Sciences, Autonomous University of Nuevo Leon, Linares,

N.L., Mexico E-mail: [email protected]

This paper discusses the advantages of structural elements composed of wood and pre-cast concrete panels. Both components are relatively light, which decreases the erection time. Related construction work does not require use of water, progress fast and need a minimum usage of scaffolding. Structural connections based on polyurethane or lag bolts are easy to realize, rigid, and safe. Keywords: composite, wood, concrete, pre-cast, polyurethane

EVOLUTIONARY APPROACH FOR COST OPTIMIZATION

OF MODIFIED MULTI-COMPONENT BINDERS

A. Amirjanov and K. Sobolev * Department of Computer Engineering, Near East University, Nicosia,

TRNC, Turkey ** Facultad de Ingenieria Civil, Universidad Autonoma de Nuevo Leon

AP #17, Ciudad Universitaria, San Nicolás de los Garza N.L. 66450, Mexico E-mail: [email protected]

This paper describes the application of a genetic algorithm for the cost optimization of a modified multi-component binder (MMCB). An MMCB comprised of Portland cement (NPC), finely ground mineral additives (fly ash, ponded ash or granulated blast furnace slag), and a highly reactive powder component (usually silica fume, SF), was modified by a superplasticizer (SP). Strength models based on the experimental results were developed. The minimization of the MMCB cost for specific strength levels using changing range genetic algorithm (CRGA) is described. The developed CRGA is based on an approach that adaptively shifts and shrinks the size of the search space to the feasible region. The application of CRGA helps to minimize the cost of MMCB with a low resolution of the binary representation scheme and without additional computational efforts.

Keywords: genetic algorithm, cost optimization, modified multi-component binder, fly ash, ponded ash, granulated blast furnace slag, reactive powder, silica fume, superplasticizer


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CONCRETOS PARA USO ESTRUCTURAL ECONÓMICOS, DURABLES Y SUSTENTABLES CON ALTO CONTENIDO DE

CENIZA VOLANTE

Alejandro Durán Herrera y Jorge Maurilio Rivera Torres Departamento de Tecnología del Concreto

Facultad de Ingeniería Civil – UANL AP #17, Ciudad Universitaria, San Nicolás de los Garza N.L. 66450, Mexico


Es posible fabricar concretos de alto comportamiento en un proceso holístico que considere un bajo consumo de cemento Pórtland, que resulte económico al incluir volúmenes importantes de ceniza volante en una acción sustentable que origina alta durabilidad y al utilizar un aditivo superfluidificante se puede lograr alta trabajabilidad y mayor resistencia. El trabajo consistió en fabricar cinco series de concretos con un consumo bajo y constante de cemento Pórtland de 150 kg/m3, variando el consumo de ceniza volante (CV) en adición de 30%, 60%, 90%, 120%, y 150%. Adicionando aditivo superfluidificante (SF) se produjo un concreto muy fluido con consistencia de 55.0 cm. de fluidez DIN. Al ir aumentando el consumo de CV la resistencia a la compresión se incrementó en forma importante, con excepción del caso de consumos de CV mayores al 120%. Para contenidos de CV mayores del 120% la resistencia a la compresión disminuye debido a que no alcanza a darse la reacción puzolánica por la falta de agua, por lo que se presentó algo de dificultad para trabajar con el mismo consumo de cemento Pórtland de 150 kg/m3. Con la mezcla de referencia se obtuvo una resistencia a la compresión de 75 kgf/cm2 y al agregar CV y aditivo SF se alcanzó una resistencia a la compresión de 495 kgf/cm2 (660%) a la misma edad y al año una resistencia a la compresión de 820 kgf/cm2 (1093%). Además se observo que al ir incrementando el consumo de CV los concretos producidos eran menos permeables y con menores retracciones por secado. Logrando por lo tanto concretos con altas resistencias a la compresión con un bajo consumo de cemento Pórtland, es decir más económico para las resistencias logradas al utilizar volúmenes importantes de CV que hacen un concreto más impermeable y por lo tanto más durable a los ambientes agresivos, se disminuye el calor de hidratación, y por lo tanto se minimizan los agrietamientos. Palabras clave: ceniza volante, trabajabilidad, superfuilidificante, compresión, durable, economía.


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INVESTIGATIONS ON NEW POZZOLANIC MATERIAL FOR CONCRETE INDUSTRY

Ibrahim M. Metwally and Hanan Anwar

R.C. Department - Housing & Building Research Centre 87, Tahrir St., Dokki, Giza – 11511, Egypt.


This paper shows the possibility of using waste glass (that is produced from fluorescent lamps factories during industrialization and operating processes) as a supplementary cementing material. The aim of this research is to study the effect of very fine waste glass (FVWG) substitution on the characteristics of ordinary portland cement (OPC) paste and mortar. Microstructure observations of FVWG by scanning electron microscopy and X-ray diffraction analysis were performed. Different mixes of OPC and various proportions of FVWG were prepared and hydrated up to 90 days. The physico-mechanical properties of each mix were measured such as, water of consistency, setting times, soundness, and compressive strength. Also, the hydrated behavior (chemical properties) was followed by measuring the free lime content, combined water content, bulk density, and porosity. The results obtained from this research confirmed that VFWG has a remarkable pozzolanic activity. It can be used as a supplementary cementing material and will significantly improve some basic properties of cement.

Keywords: waste glass, cement, microstructure, setting times, compressive strength, bulk density, porosity

MICROSTRUCTURE OF ECO-CEMENT WITH HIGH VOLUMES OF WASTE GLASS

P. Türker*, K. Sobolev**, P. Valdez** and G. Iscioğlu***

* Cement and Concrete Research Institute of TCMA, Turkey ** Facultad de Ingenieria Civil, UANL, Mexico

*** BEM Cement, TRNC, Turkey E-mail: [email protected]

This report examines the effect of waste glass materials (window glass, black-and-white monitor glass, brown and green bottle glass) on the microstructure and strength of ECO-cement based materials. SEM investigations were used to observe the changes in C-S-H, CH and interface between the cement matrix and waste glass particles. The SEM observations detected a visible densification around the glass grains, due to partial hydration of glass grains and formation of an additional C-S-H. According to the SEM investigation, the main difference between the glass cement pastes and the reference portland cement, is related to the decrease in the size and the amount of CH, caused by the consumption of CH as a result of pozzolanic reaction involving glass grains. No sign of ASR was found in the


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investigated samples of waste glass cement. According to the research results, the developed ECO-cement containing 50% of waste glass possessed flexural and compressive strength properties at a level similar to normal portland cement, in the range of 6.9- 7.3 and 44.5- 66.7 MPa, respectively. Best compressive strength values were demonstrated by the ECO-cement based on waste window and green bottle glass. Keywords: waste glass, microstructure, strength, ECO-cement, SEM, C-S-H, hydration, compressive strength

FEASIBILITY ANALYSIS OF ECO-CEMENT

Metin Arikan Department of Civil Engineering, Middle East Technical University

Ankara 06531, Turkey E-mail: [email protected]

The world production of cement has significantly increased in recent years. This trend is one of the most significant factors affecting the technological development of cement industry and updating the manufacturing facilities. However, existing portland cement technology has adverse ecological effects, such as consumption of large amounts energy and natural resources and emission of a number of pollutants. The production of blended cement using High - Performance Eco-Cement technology increases the compressive strength of ordinary cement and improves the durability of cement-based materials; this technology also allows the utilization of high volume of inexpensive mineral additives or industrial by-products. In this study, a feasibility analysis was carried out for Turkish cement manufacturers to demonstrate that it is profitable for the cement manufacturers to invest in high performance cement manufacturing. The effects of various parameters on the investment such as sale price, loan amount, interest rate, expected rate of return, etc. were also studied. Keywords: cement, manufacturing, ecological, economical, profitability, investment


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DURABILITY AND CORROSION

THE ROLE OF PRIMERS TO THE REINFORCING STEEL IN CONCRETE CONSTRUCTIONS

Pedro Castro-Borges

Centro de Investigación y Estudios Avanzados del IPN - Unidad Mérida km 6 Antigua Carretera a Progreso, 97310 Mérida, Yucatán, México


The decaying infrastructure of our countries needs a special attention in terms of developing and using techniques for controlling the deterioration processes. The selected technique will depend on several factors which include those of the environment and economics. In developing countries, the use of primers/coatings, as protection to the reinforcing steel, is very common as a repair and/or corrosion prevention method. However their application involves several pitfalls and misunderstandings that need to be addressed carefully. One of the most known cases is that of the Mexican Coasts, where millions of primer liters are used to protect or to repair the concrete constructions. There are successful cases but unsuccessful ones too. The objective of this paper is to describe the working mechanisms of the primers and to discuss several results of research of this topic in tropical marine environment. Some of the results helped to construct tables of efficiency for the primers and others indicated that the galvanic couple formed between the repaired and non-repaired zones last a few time only. Keywords: primers, reinforcing steel, concrete, repairs PERFORMANCE OF A 40-YEAR OLD CONCRETE BRIDGE WITH EMBEDDED PRE-STRESSED GALVANIZED STRANDS

Paulo Helene*, M. F. Pereira**, P. Castro***

*Escola Politécnica da Universidade de São Paulo, Instituto Brasileiro do Concreto IBRACON, São Paulo, Brazil **University of Montevideo, Uruguay

***Centro de Investigación y Estudios Avanzados del IPN Unidad Mérida, km 6 Antigua Carretera a Progreso, 97310 Mérida, Yucatán, México

E-mail: [email protected] Despite recent literature prevent the use of pre-stressed galvanized steel in concrete, it was detected a bridge constructed with pre-stressed galvanized strands embedded in concrete that has been in service for more than 40 years showing adequate behavior. A detailed inspection of this Uruguayan National Monument was performed using electrochemical, mechanical, physical and chemical techniques on site and laboratory. Contrary to the


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expected, the results indicated that some strands have developed corrosion that produced ductile failures on only some wires and that deterioration has been mainly due to insufficient concrete cover that produced strand exposure to the atmosphere instead of stress corrosion or hydrogen embrittlement. Keywords: pre-stressed, galvanized, steel, concrete, electrochemical, mechanical, failure, strand, corrosion CORROSION OF PRE-PAINTED GALVANIZED STEEL STRIP

FOR THE CONSTRUCTION INDUSTRY

Armando Salinas Rodríguez CINVESTAV Unidad Saltillo, P.O. Box 663, Saltillo, Coahuila, México 25000


Durability of paint coatings on galvanized steel strips depends on its (a) internal strength and (b) adhesion to the Zn substrate. In general, paint failure mechanisms involve mechanical damage due to erosion and impact which cause cracking and breaking of chemical bonds in the polymeric matrix of the paint system. This last mechanism is associated with the occurrence of hydrolysis and oxidation reactions, exposure to ultraviolet radiation from the sun and exposure to water. Water exposure results directly from rain or snow or can be formed on the surface of the paint coating by condensation of ambient humidity due to temperature cycling. In the present work it is shown how light surface damage of the paint coating of pre-painted galvanized steel coils, produced during handling and storage, can cause catastrophic corrosion of the Zn coating and lead to paint delamination and extensive formation of blisters, even in apparently sound regions of the coating. Keywords: durability, paint coating, galvanized steel, delamination, corrosion, Zn coating


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STUDY OF THE CORROSION OF HIGH RESISTANCE RODS BY TEMPCORE® PROCESS IN REINFORCED CONCRETE

SPECIMENS

Jorge Arellano*, Francisco Aguilar*, G. Fajardo**, D. I. Martínez*

*Facultad de Ingeniería Mecánica y Eléctrica-FIME, **Facultad de Ingeniería Civil-FIC

Universidad Autónoma de Nuevo León ave. Pedro de Alba s/n, Cd. Universitaria, San Nicolás de los G., NL, México.


The process known as Tempcore is used to produce high resistance rods by the formation of a surface layer of quenched and tempered martensite that surrounds a core made of ferrite and pearlite. Such a mixed structure is result of processing hot rolled rods through waters headers that reduce the temperature at the surface below that for the transformation into martensite. This structure is tempered by the heat flowing from the core of the rod, which transforms into ferrite and pearlite while the rod is in the cooling beds. Such processing produces a significant increase in yield and ultimate tensile strength, while maintaining adequate ductility. The economic advantages of this process are huge in comparison with those that require alloying elements or further metal working to improve mechanical properties. A series of experimental trials were carried out in a pilot plant in which parameters such as reheating temperature, water flow and processing time were varied to study their effect on the mechanical properties of carbon steel rods and on the structures formed in the bars. The study is being complemented by to determine the resistance to the corrosion of the rods of high resistance embedded in concrete exposed to chlorides through electrochemical techniques. Also, the characterization of the products of corrosion of the rods absorbed in concrete and service life prediction were carried out. The steels to study have the following chemical composition: a steel G40 within and without Tempcore process (0.26%C, 0.85%Mn, 0.146%Si, 0.023%P and 0.038%S) and a commercially steel R42 (0.36%C, 1.04%Mn, 0.18%Si, 0.013%P and 0.029%S). Keywords: Tempcore process; high resistance rods, corrosion; service life prediction; reinforced concrete.


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COMPARING THE CORROSION ACTIVITY OF STEEL REINFORCEMENT IN CONCRETE WITH NaCl AND CaCl2

ADDITIONS USING OPC CONCRETE

A.I. Cárdenas*, J.M. Miranda**, F. Almeraya*, L. Narváez**, E. Martínez** *Centro de Investigación en Materiales Avanzados (CIMAV), Miguel de

Cervantes 120, Complejo Industrial Chihuahua, Chihuahua, México. **Instituto de Metalurgia, Universidad Autónoma de San Luis Potosí, Av.

Sierra Leona No. 550, Col. Lomas 2ª Sección 78210, San Luis Potosí, México E-mail: [email protected]

The corrosion of reinforcing steels in concrete is the one main reason for the durability problems of Reinforced Concrete Structures (RCS). The useful service-life of the RCS is drastically reduced because of this phenomenon. This problem occurs mainly when the rebar in the concrete is exposed to the presence of chlorides, as result of the use of contaminated ingredients on the manufacture of the mix, from exhibition in marine atmospheres, for the use of de-icing salts (NaCl, CaCl2, MgCl2) a necessary practice in cold climates, or from accelerating admixtures. In this work a comparative of the corrosion rates was carried out and corrosion products of samples of armed concrete is made so much prepared with addition of NaCl, as of CaCl2, adding in both cases 3% (for cement weight). For the two cases Ordinary Portland Cement (OPC40R) was used with a water/cement ratio (w/c) of 0.45 and 0.65. In each one of the samples 2 steel bars were embedded. The experimentation was during 365 days, maintaining a bigger relative humidity to 90%. The corrosion rates was evaluated by means of the Linear Polarization Resistance (LPR) and the likelihood of corrosion was measured with Half-cell potential (Ecorr). The samples with NaCl showed a light change in the corrosion rates from 120 days of experimentation, being smaller in the samples with a relacion w/c of 0.65, however, in the samples with CaCl2 similar corrosion rates were observed during the measurements. Keywords: concrete, chlorides, corrosion rate, corrosion products

MORTEROS CON PUZOLANAS NATURALES MEXICANAS: EFECTOS SOBRE LA CORROSIÓN DEL ACERO INDUCIDO

POR CLORUROS

G. Fajardo, P. Valdez, J. Pacheco, J.G. Montemayor Facultad de Ingeniería Civil, Universidad Autónoma de Nuevo León

av. Universidad s/n, Cd. Universitaria, San Nicolás de los Garza, NL, México E-mail: [email protected]

La corrosión del acero de refuerzo en las estructuras de concreto es el principal problema de durabilidad y que preocupa seriamente al sector de la construcción en todo el mundo. Para prolongar su durabilidad, reducir los


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costos de producción y disminuir la emisión de gases de efecto invernadero, se ha optado por emplear materiales cementantes complementarios. México cuenta con zonas volcánicas importantes en las cuales se pueden obtener materiales naturales con potencialidad puzolánica. A estos materiales se les conoce también como puzolanas naturales. En este trabajo se analizó la utilización de una puzolana natural como reemplazo del cemento Pórtland ordinario en especímenes de mortero reforzado. Para ello se emplearon dosificaciones de 0, 10 y 20% de puzolana natural como sustitución en peso de una parte de cemento. Se fabricaron cilindros de mortero con un acero embebido en el centro de los mismos. Los especímenes fueron expuestos a ciclos de inmersión en una solución de 35 g/L de NaCl y secado a 40 °C, para acelerar el proceso de penetración de los iones agresivos. Las técnicas experimentales de resistencia a la compresión, potencial de electrodo del acero, resistividad eléctrica del mortero y resistencia a la polarización fueron aplicadas con el objetivo de caracterizar física, mecánica, eléctrica y electroquímicamente a los especímenes de mortero. De este modo, se determinó la extensión de la vida útil de los especímenes de mortero como una medida de la efectividad de las puzolanas naturales utilizadas en función del porcentaje de sustitución empleado. Palabras clave: corrosión; durabilidad; puzolanas naturales; vida útil

EVALUACION DE LA CINETICA DE CORROSION DEL ACERO G-42 SOMETIDO A 750 Y 960 oC

F. González*, D. Hernández**, G. Fajardo**, P. Valdez**

*Dept. de Materiales-Área de Construcción, Universidad Autónoma

Metropolitana Azcapotzalco, San Pablo 180, DF, México **Facultad de Ingeniería Civil, Universidad Autónoma de Nuevo León,

av. Universidad s/n, Cd. Universitaria, San Nicolás de los Garza, NL, México E-mail: [email protected]

La principal problema de durabilidad en las estructuras de concreto reforzado es la corrosión. En algunos países los costos de reparación se han incrementado hasta 5% del PIB. Los factores y condiciones ambientales que influyen en este tipo de deterioro son diversos. En el presente trabajo se estudian los efectos del acero de refuerzo en elementos estructurales que han sido sometidos a temperaturas extraordinarias. Para evaluar el comportamiento a la corrosión de varillas usadas en construcciones dañadas por incendio, se propuso someter a altas temperaturas (750 y 960 ºC) una serie de barras del G-42, las cuales posteriormente fueron enfriadas súbitamente. En seguida se embebieron en especimenes cilíndricos en concreto hidráulico. Para inducir el proceso de corrosión, se uso NaCl disuelto en el agua de mezclado. El seguimiento de la reacción electroquímica se llevo a cabo mediante mediciones periódicas, adoptando


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como variables el potencial y la velocidad de corrosión. Para la evaluación de las propiedades físicas y mecánicas de los diferentes tipos de varillas, se realizaron metalografías, medidas de microdureza y pruebas de tensión directa. Los resultados preliminares obtenidos permiten afirmar que la cinética de corrosión en las varillas se ve modificada por el calentamiento. En general, las velocidades de corrosión de las varillas sujetas a 960 ºC es menor con respecto a las demás, se infiere que la modificación microestructural de la fase mineralógica presente en la superficie de la varilla podría ser la causa de dicho comportamiento. Palabras clave: corrosión, concreto reforzado, potencial de corrosión, martensita. PORQUE LAS EDIFICACIONES NO SON DURABLES EN EL

NORESTE DE MÉXICO

Rodolfo Meza Salas y José Roberto Acosta Flores Institute de Ingeniería Civil, Universidad Autónoma de Nuevo León

av. Universidad s/n, Cd. Universitaria, San Nicolás de los Garza, NL, México E-mail: [email protected], [email protected]

El concreto reforzado como material de construcción en México continúa como líder sobre el acero estructural. El auge de este material se inicia en los años 60’s y 70’s del siglo pasado y su durabilidad se ha reducido por las condiciones climáticas extremas, así como con la contaminación ambiental con el incremento de la industria en general y la quema de combustibles derivados del petroleo. Aunado a lo anterior, en el uso del suelo hasta hace pocos años se han estado ejerciendo nuevas normativas para el control de las edificaciones existentes, por tal razón cuando estos han fallado, se han debido entre otros al aumento de las instalaciones eléctricas no planeadas de origen que han generado incendios. Por otra parte el incremento en los niveles de las edificaciones ha llevado a la condición crítica a estos hasta un estado de falla local y en casos extremos hasta la falla general o colapso. A la fecha cuando se realizan rehabilitaciones, estas se efectúan todavía en la forma antigua tradicional sin tomar en cuenta los nuevos materiales con tecnología de punta para tal fin. Si bien es cierto que la industria del concreto premezclado en México está vigente con la tecnología moderna, con excepciones, no ocurre lo mismo con la supervisión, ni mucho menos con la mano de obra calificada, debido a que se ha perdido el estado del arte del concreto hidráulico. Palabras clave: concreto reforzado, concreto premezclado, concreto hidráulico, material de construcción, durabilidad


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POSTER SESSION

CHARACTERIZATION OF MODIFIED ASPHALT WITH

DIFFERENT POLYMERS

G. Hernández-Padrón*, M. L. Pérez-Rea ** and R. Blanco Pérez*** *Centro de Física Aplicada y Tecnología Avanzada

Universidad Nacional Autónoma de México Juriquilla, Querétaro, A. P. 1-1010, Querétaro 76000, México. **División de Estudios de Posgrado,. Facultad de Ingeniería

Universidad Autónoma de Querétaro C.U. Cerro de las Campanas S/N. C.P. 76010, Querétaro, México.

*** Chovatek, S.A. de C.V., Impermeabilizantes Prefabricados Carr. a Monclova km. 19.5 CP 65650, Abasolo, Monterrey N. L., México.

E-mail: [email protected] Polymer modified asphalt (PMA) is used in many construction applications, being the most important roadways and roofing. In order to improve their performance, asphalts are often modified by addition of polymers. The polymers could be elastic or thermoplastic materials. The properties of PMAs depend on the degree of dispersion and the microstructural arrangement of both polymeric and asphalt phases, that’s why the importance to observe the shape of those structures by TEM. Microstructural shapes and rheological characterization of Styrene-Butadiene-Styrene (SBS), Ethylene-Vinyl-Acetate (EVA) and Ethylene-Glycidyl-Acrylate (EGA), mixed with Asphalt were studied at different concentration of polymer from 10 to 13 wt%. Technical Characterization such as Transmission Electron Microscopy (TEM) and Dynamic Mechanical Analysis (DMA) were used. The samples were prepared in batch mixers at 1800C by 2 or 3 hours. Keywords: polymer modified asphalts, SBS polymer, EVA polymer, compatibility


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COMPRESSION STRENGTH PREDICTION OF MIXTURES CONCRETE WITH SCRAP TIRE WITH NEURAL NETWORK

APPROACH

Jorge Acevedo*, Luis Torres*, Mario Trejo*, Cesar Juárez** *Corporación Mexicana de Investigación en Materiales SA de CV. AP 491, CP

25000, Saltillo, Coahuila, México **Instituto de Ingeniería Civil, UANL, AP #17, CP 66450, San Nicolás de los

Garza, N.L., México, E-mail: [email protected], [email protected]

This aim of this study is to investigate the effect of scrap tire aggregate size on strength and moisture migration characteristics of concrete. The present study covers the employment of a neural model allows us to avoid testing a large number of trial mixtures and provides us with new alternatives for the design of new constructive components at low cost. The application of a neural model for the prediction of the compressive strength of mixtures containing variable amounts of scrap tire. The results show an excellent performance of the chosen neural model to make accurate and highly reproducible predictions. Keywords: scrap tire, aggregates, strength, moisture migration, concrete, neural models

PREPARATION OF SIO2 NANOPARTICLES USING FOR THEIR APPLICATION IN CEMENT MATERIALS

Elvira Zarazúa M., Leticia M. Torres-Martínez, Ismael Flores, and

Konstantin Sobolev

Facultad de Ingeniería Civil, Universidad Autónoma de Nuevo León av. Universidad s/n, San Nicolás de los Garza, NL, Mexico

E-mail: [email protected], [email protected], [email protected] The most of the research related to nanotechnology of construction materials is mainly focused on the investigation of the structure of the cement materials at nanometric scale. The nanotechnology also offers the possibility to produce new materials for the concrete. In this work SiO2 nanoparticles were prepared by sol-gel method. SiO2 nanoparticles were added to the cement and their effect on the microstructure of the cement materials was investigated. The results related to the synthesis of SiO2 nanoparticles and their characterization by DRX, BET, FTIR, and DTA/TG are reported. Keywords: sol-gel, SiO2, cement, concrete


35

SYNTHESIS OF C-S-H - POLYMER HYBRID NANOCOMPOSITES

Philippe Jean-Paul Gleize* and Dachamir Hotza**

*Departamento de Engenharia Civil ** Departamento de Engenharia Química e Laboratório de Materiais,

LabMat da UFSC UNIVERSIDADE FEDERAL DE SANTA CATARINA

Centro Tecnológico, Campus Universitário - Trindade - Caixa Postal 47688040-900, FLORIANÓPOLIS - SC - BRASIL

E-mail: [email protected] During the last decades, the majority of the advances in cement-based materials performances was obtained by the optimization of the aggregates and particles stacking and, especially, by the reduction of capillary porosity thanks to the rational use of more and more efficient chemical additive. However, in terms of performances, an asymptote is reached. This suggests that the improvement of the mechanical properties only can come from modifications in the finest scales of the material. The interest for nanocomposite materials (e.g.: organic/inorganic) is a consequence of this observation. The proper nature develops a fantastic and great diversity of organisms which use the advantages of this synergy: shells, bones, teeth, etc. These materials exhibit unique properties in the point of view of its tenacity, flexural strength, etc., and this with organic phase content extremely low. The understanding and the reproduction of the strategies of association between organic and inorganic phases used by the nature open great perspectives regarding the manufacture of synthesis materials with atypical properties. The research intends to synthesize nanocomposites C-S-H / polymers or organic molecules.

Keywords: C-S-H, nanocomposites, intercalation

INCORPORATION OF NANOFIBRES IN CEMENT-BASED MATERIAL

Philippe Jean-Paul Gleize and Wellington Longuini Repette

Departamento de Engenharia Civil UNIVERSIDADE FEDERAL DE SANTA CATARINA

Centro Tecnológico, Campus Universitário - Trindade - Caixa Postal 47688040-900, FLORIANÓPOLIS - SC - BRASIL

E-mail: [email protected] Two of the critical problems of high performance concrete are cracking (mainly at early ages) and its fragility. It is believed that nanofibres can act as bridges that can transfer the tensile stress generated by capillary


36

depression in pores and, can be a solution to lower the cracking occurrence at early ages of cement-based materials. The fragility of concrete increases with the increase of its mechanical strength. The reinforcement of the C-S-H structure with nanometric fibers can allow to produce cement-based materials with higher strength, but also with a ductile behavior. The research intends to incorporate high content of nanofiber in cementitious materials. Keywords: nanofibers, C-S-H structure, concrete, shrinkage, strength, ductile behavior

ADDITION OF POLYPROPYLENE FIBERS AS A NEW APPROACH TO MODIFICATION OF DENSE BITUMINOUS

MIXTURES

Serkan Tapkin Civil Engineering Department, Anadolu University, Eskisehir, 26555, Turkey

E-mail: [email protected] Scientists and engineers are trying to improve the performance of dense bituminous mixtures, namely asphalt for many years. Modification of bitumen is one of the approaches followed in order to improve the performance of pavements. It is believed that the addition of polypropylene fibers to asphalt enhances the material strength by extending fatigue life, exhibiting good resistance to rutting and resulting in less reflection cracking. Because of their inherent compatibility with asphalt cement and excellent mechanical properties, polypropylene fibers offer an excellent potential for asphalt modification. In this study, the standard Marshall specimens were prepared by utilizing optimum bitumen content with and without polypropylene fibers. It was found out that the Marshall stability values have increased and the flow values have decreased considerably. The fatigue lives of the Marshall specimens have been found to increase after carrying out repeated load indirect tensile tests. These changes in the mixture properties demonstrate the positive effects of polypropylene fibers to dense bituminous mixtures. Keywords: dense bituminous mixtures, polypropylene fibers, Marshall test, repeated load indirect tensile tests, fatigue life


37

SUCCESSFUL APPLICATION OF PRESTRESSED CONCRETE PAVEMENT (PCP) IN TEXAS

Cesar Medina Chavez and Moon Won

Center for Transportation Research, The University of Texas at Austin, 3208 Red River, Suite 104, Austin, Texas 78712, USA

E-mail: [email protected], [email protected]

Although prestressed concrete pavement (PCP) has been around for over 60 years, its application in the United States is starting to gain popularity due to its success and for being considered a low-maintenance high performance concrete pavement. A one-mile cast-in-place test section of PCP was built in 1985 on IH 35 southbound lanes in Waco, Texas. The concrete slab is 6-in. thick with 240-ft. and 440-ft. joint spacings. For over 20 years, this PCP section has performed exceptionally well under heavy truck traffic conditions. The pavement shows no signs of distress, except for limited longitudinal cracks at rectangular stressing pockets. These cracks are very fine and appeared at a very early age of the structure and since then have not worsened. Based on the excellent performance of this section over the last twenty years, the Texas Department of Transportation (TxDOT) decided to construct two more PCPs in the State. A precast PCP pilot project was constructed in 2002 on a section on frontage road along IH 35 near Georgetown, Texas. This project evaluated the concept of prestressed concrete panels that helped to develop viable design and construction techniques for expedited construction in urban areas. Another cast-in-place PCP will be constructed near Hillsboro, Texas in 2006. This new PCP will be nearly 12 mile-lanes, which makes it the largest project in its class. Based on the excellent performance of previous PCP in Texas, it is expected that the new PCP will provide even better long-term performance at a competitive cost, when compared to other pavement alternatives. Keywords: PCP, stressing pocket, cast-in-place, precast

MANUFACTURED SAND FROM ROCK

John Googins 7609 South Hahns Peak, Littleton, Colorado 80127, USA


This presentation will look at manufactured sand from rock using all kinds of machines such as Cone Crushers, Rod Mills, Roll Crushers, VSI. It will include analysis of production rates, operating cost, power consumption, wear parts, gradations, particle shape, recirculating loads, crusher efficiencies and classification to concrete sand. The presentation will also consider the fineness modulus of classified concrete sand and how to achieve a suitable


38

product. We will also explore the blending of natural sand and manufactured sand to achieve "Mass Flow Balance" in aggregate plants. Keywords: manufactured, sand, rock, cost, power consumption, gradation, particle shape EVALUACIÓN DE LA EFICACIA EN LA REALCALINIZACIÓN

DE CONCRETO REFORZADO CARBONATADO

F. González*, G. Fajardo**, G. Arliguie***, C. Juárez** *Departamento de Materiales - Área de Construcción Universidad Autónoma Metropolitana Azcapotzalco

San Pablo 180 DF México **Facultad de Ingeniería Civil, Universidad Autónoma de Nuevo León

av. Universidad s/n, Cd. Universitaria, San Nicolás de los Garza N.L México ***Laboratoire Matériaux et Durabilité des Constructions INSA

Université Paul Sabatier 135 Avenue de Rangueil 31077 Toulouse Cedex 4 France


Las estructuras de concreto reforzado están sujetas a una gran variedad de mecanismos de degradación. Es la corrosión del acero de refuerzo la principal causa de los altos costos económicos derogados por los países que padecen dicho problema en su infraestructura. El objetivo de las diversas técnicas de prevención y reparación por corrosión es eliminar y/o controlar alguno de los elementos básicos del mecanismo de degradación por corrosión en las estructuras. La elección de la técnica para cada caso en particular depende de varios factores, entre los que destaca el mecanismo de ataque. Para prevenir o detener la carbonatación que induce la corrosión del acero de refuerzo, la técnica de realcalinización electroquímica es usada comercialmente desde hace dos décadas como un tratamiento de rehabilitación. Sin embargo, se tiene muy poca certidumbre sobre cuales son los parámetros que evalúan la eficacia de la técnica. El objetivo del presente trabajo es aportar datos experimentales que no solo conduzcan a un mejor entendimiento de la técnica, si no que permitan identificar y analizar los parámetros y los criterios de operación que influyen en la funcionalidad y aplicabilidad del método. Palabras clave: concreto reforzado, carbonatación, corrosión, realcalinización.


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CASING MATERIALS IN GEOTHERMAL APPLICATIONS FOR CORROSION CONTROL

Juan de Dios Ocampo D.,* Benjamín Valdez S.,** Miguel Schorr W.,**

Israel Suceda M.,* Héctor Muñiz V.* *Facultad de Ingeniería, Mexicali, Universidad Autónoma de Baja California, Blv. Benito Juárez, s/n, C.P. 21900, Mexicali, B.C, México **Instituto de Ingeniería, Departamento de Materiales y Corrosión,

Universidad Autónoma de Baja California, Blv. Benito Juárez, s/n, C.P. 21900, Mexicali, B.C, México E-mail: [email protected]

Geothermal steam and brine exhibit extreme corrosion characteristics. Corrosion attack occurs during geothermal operation resulting in severe equipment damage. Production well steam and brine gathering systems, injection lines and wells interact with the aggressive components of geothermal steam and brine. The production casing string in geothermal wells are subjected to internal and external corrosion from the production or reinjection fluid on the casing inside and from the reservoir fluids on the casing outside. The casing is also damaged by mechanical wear, particularly if the production casing is deviated of the vertical, from rotating drill string in the well during drilling or workover. There are multiple mechanisms of corrosion attack contributing to the failure of the casing production. These mechanisms involve several contaminants and conditions: carbon dioxide (CO2), hydrogen sulfide (H2S), iron sulfide (FeS), sulfuric acid, dissolved oxygen (O2), temperature, suspended solids, flow hydrodynamics, etc. Therefore, often is necessary to replace the well casing production, damaged by corrosion using different casings with diverse properties. This paper present the main problems in the casing production of geothermal wells associated with corrosion, and the solution strategies based on new casing material and properties. Keywords: corrosion, casing material, geothermal, production well CORROSION PREDICTION AND ANNUAL MAINTENANCE

OPTIMIZATION OF CONCRETE STRUCTURAL COMPONENTS USING NEURAL NETWORK MODELING

A. Cheang-Martínez, J.L. Acevedo-Davila, L. Treviño-Torres y

F.A. Reyes Valdes Corporación Mexicana de Investigación en Materiales SA de CV

AP 491, 25000, Saltillo, Coahuila, México E-mail: [email protected]

Concrete columns and other structural components used in Zinc electrolysis facilities are strongly affected by an aggressive, sulfuric acid rich


40

environment, resulting in very expensive annual repairs. Neural network modeling is a recently developed alternative to determine where and how the structural damage on concrete columns is taking place. This neural network model was fed by four-year maintenance registries data. Modeling showed that the most affected concrete components are those located near liquid zinc crucibles. Neural network model also helped to develop a more accurate preventive maintenance schedule and optimizing the annual repairs investment. Keywords: concrete degradation, neural networks, modeling

ACEROS DE CONSTRUCCIÓN DE PROPIEDADES ESPECIALES

Zygmunt Haduch

UDEM, Monterrey, México E-mail: [email protected]

El problema siempre actual en caso de acero como un material de construcción es la pregunta: ¿como llegar a alta resistencia y buena deformabilidad de acero en el mismo tiempo? Aumentando los elementos de aleación especialmete el carbono, sube la resistencia mecánica de acero pero se pierde las propiedades plásticas del material. Antes para la carrocería de autos se aplicaba acero al bajo carbono sin elementos de aleación, los que si cumplía factor o propiedad de buena deformabilidad pero con baja resistencia mecánica lo que causaba aumento de espesor de la lamina y aumento de peso de la construcción. En los últimos años se elaboró varios tipos de aceros los que unen estas dos propiedades; resistencia y deformabilidad. Esto son los aceros HSLA, TRIP, bifásicos, tipo “dual” entre otros. Varias companias automotriz, entre ellos TOYOTA, ya fabrica chasises de sus automóbiles de los aceros 30% mas resistentes lo que significa disminuición significativa de peso. En la ponencia se presentará las últimas novedades en el diseño de aceros de propiedades especiales, de alta resistencia y de deformabilidad que sobrepasa 1000% y de excelente soldabilidad, lo que es un futuro en aplicacion de aceros de construcción. Palabras clave: acero, material de construcción, alta resistencia, deformabilidad, soldabilidad


41

AUTHOR’S INDEX J. Acevedo 34 J.L. Acevedo-Davila 39 J.R. Acosta Flores 32 F. Aguilar 29 F. Almeraya 30 A. Alvarez-Méndez 16 J. Ambroise 4 A. Amirjanov 23 M. Angeles Rechy 23 C. Angulski da Luz 4 H. Anwar 25 J. Arellano 29 M. Arikan 26 G. Arliguie 38 J.C. Arteaga A. 17 H. Balmori-Ramírez 16 R. Blanco Pérez 33 J. Bolander 6 A.I. Cárdenas 30 C. Castillo-Linton 9 P. Castro 27 A. Cheang-Martínez 39 O. Chimal Valencia 15, 17 Y. Chun 11,12 V. Corinaldesi 6 M.S. Corral García 15 H. Cuadros Abad 19 S. Díaz de la Torre 15, 17 J. Dios Ocampo D. 39 A. Durán Herrera 24 R. Elba Rodríguez 14 G. Fajardo 29, 30, 31, 38 J.J. Flores Martínez 14, 21 I. Flores 17, 34 M.V. Folgueras 13 L.L. Garza-Tovar 17 P. Gleize 13 F. González 31, 38 F. González J. Googins 37 B. H. Green 9 Z. Haduch 40 P. Helene 7, 27 R. Hermosillo 16 D. Hernández 31 G. Hernández-Padrón 33 D. Hotza 13, 35 G. Iscioğlu 25 A. de Ita de la Torre 15

P. Jean-Paul Gleize 35 F.J. Jiménez-Alvarez 16 C. Juárez 34, 38 R. E. Klingner 4 S.J. Kokkins 5 R.N. Kraus 11, 12 S.B. Kristoff 5 V.C. Li 19 R. A. Livingston 5 W. Longuini Repette 35 P. Lopez-Armendariz 9 W. Lopez-Gonzalez 9 J. M. Lugo Cuevas 14 R. Lusignea 5 M. Malhotra 21 G. Mañón-Barroso 20 A. Márquez Lucero 14 B. Martínez 14 B. Martínez Sánchez 21 D.I. Martínez 29 E. Martínez 30 G. Martínez-Barrera 20 C. Medina Chavez 37 I.M. Metwally 25 R. Meza Salas 32 J.M. Miranda 30 H. Montaño 14 H.J. Montaño Román 21 J.G. Montemayor 30 G. Moriconi 6 H. Muñiz V. 39 T.R. Naik 11,12 L. Narváez 30 M. Olín-Ramírez 20 H. Orozco Recillas 19 C.P. Ostertag 10 J. Pacheco 30 J. Pera 4 M. F. Pereira 27 D.S. Perera 12 M. L. Pérez-Rea 33 J. Player 5 R.S. Ravindrarajah 22 W.L. Repette 13 F.A. Reyes Valdes 39 J.M. Rivera Torres 24 K. Rodríguez Carmona 14 R.E. Rodríguez Camacho 21 W. von Roth 23

A. Salinas Rodríguez 28 M. Schorr W. 39 L. Senff 13 J. Slade 5 K. Sobolev 16, 23, 25 I. Suceda M. 39 S. Tapkin 36 L. Téllez-Jurado 16 L.M. Torres-Martínez 17, 34 M. Trejo 34 L. Treviño-Torres, F.A. 39 P. Türker 25 R. Uribe Afif 14, 21 P. Valdez 25, 30, 31 B. Valdez S. 39 M. Won 37 E. Zarazúa M. 34

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