Types of Concrete

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  • 1. 1 | P a g e School of Architecture, Building and Design Bachelor of Quantity Surveying (Hons) Building Material Assignment 1A- Concrete Date: 29 April 2014 Group Members: Goh Jeng Jhieh (0315080) Cassandra Wong XinYue (0313365) Wong Yun Shi (0315225) Mak Mun Choon(0314928) Liu WeiCheng

2. 2 | P a g e Content Content Page Front Page 1 Content 2 Introduction 3 Types of Concrete : 3A Aerated Aerated Autoclaved Concrete 4-6 : 3B Asphalt Concrete 7-11 : 3C Seacrete Concrete 12-14 : 3D Decorative Concrete 15-17 : 3I Roller Compacted Concrete 18-19 References 20-21 3. 3 | P a g e Introduction 4. 4 | P a g e 3A Autoclaved Aerated Concrete Detail view of AAC in 1mm Definition Of AAC Autoclaved Aerated Concrete (AAC) is a comparatively new building material in North America. Other than that, it has been widely used in Europe and also Asia as a green construction material. The concrete is one-fifth the weight of normal concrete and it has thermal efficiency that has the ability to reduce a building's energy consumption by 30-40 percent. Autoclaved Aerated Concrete is easily to cut any required shape. Advantages AAC has been produced more than seventy years. It also offers several advantages over other cement construction materials. The advantages are; AAC reduces additional material use AAC has high thermal efficiency Minimize waste and pollution AAC reduce noise pollution and improve indoor air quality AAC structure are superior to withstand fires, earthquake, and other natural disasters AAC structure are price competitive Larger size lead to fast masonry work 5. 5 | P a g e Disadvantages There are few disadvantages with Autoclaved Aerated Concrete, which are; Projects far from manufacturing facilities will suffer with higher initial costs. Contractor experience. They have to adjust to apply thin-set mortar to light weight blocks, which is a skill that requires more precision. Load-bearing limitation. ACC less suitable for high-rise buildings. Material properties AAC ranges in density from 25-50 lb with compressive strengths ranges from 290 psi to 1090 psi. It also suitable for loadbearing and non-loadbearing walls.AAC mansory blocks are available in a variety sizes. The nominal face dimensions are 8 high by 24 long with nominal thickness of 2, to 16 U block Modular block AAC consider as green &environmental building material Main ingredient which are quartz sand, cement, lime and water all are available. AAC any production waste before the final setting will be reintroduced into the production cycle. There is any pollution either water or air AAC left over the site building can be recycled. Eg.foundation fill back or crash and use for. It no contains toxic substances 6. 6 | P a g e Process of making AAC 1. Raw materials which are sand, cement, lime and water. 2. Mixing the raw materials 3. Slurry was poured into mold 4. Procuring stage 5. Cake is separated from mold 6. Mold will be returned for next step 7. Cake is ready to be cut 8. Mold was cleaned 9. Mold is oiled 10.Mold closes 11.Mold returns to mixer 12.Cake is cut in to blocks or panels and waste is recycled 13.Uncured AAC placed into autoclave under steam & pressure 14.Cured AAC removed from autoclave 15.AAC is shrink wrapped and placed on pallets 16.AAC transported for shipping or to storage area 7. 7 | P a g e 3B-ASPHALT CONCRETE DEFINITION Asphalt is well known as a road covering, more technically termed asphalt concrete, but there are a few different forms in which the substance may appear. It is a naturally occurring material present in crude oil and in natural deposits, notably around certain bodies of water and in oil sands. This substance is found in either liquid or semi-solid form in nature and is characterized by its high viscosity and its sticky, black appearance. It consists almost exclusively of bitumen, a substance composed of polycyclic aromatic hydrocarbons (PAHs). 8. 8 | P a g e GENERAL INFORMATIONS ROLLED ASPHALT - It is made of aggregate or solid materials such as sand, gravel, or recycled concrete. This type is used to make roads and other surfaces, such as parking lots, by being applied in layers and compacted. HOT MIXED ASPHALT CONCRETE (HMAC) - It is produced at 320F (160C). This high temperature serves to decrease viscosity and moisture during the manufacturing process, resulting in a very durable material. HMAC is most commonly used for high-traffic areas. WARM MIXED ASPHALT CONCRETE (WAM OR WMA) - It reduces the temperature required for manufacture by adding emulsions, waxes, or zeolites. This process benefits both the environment and the workers, as it results in less fossil fuel consumption and reduced emission of fumes. COLD MIXED ASPHALT CONCRETE - This type of asphalt is emulsified in soapy water before mixing it with the aggregate, eliminating the need for high temperatures altogether. However, the resulting material is not nearly as durable as HMAC or WAM, and it is typically used for low traffic areas or to patch damaged HMAC. 9. 9 | P a g e USAGE OR APPLICATION OF ASPHALT CONCRETE -Transportation (roads, railway beds, airport runways) -Recreation (playgrounds, bicycle paths, running tracks) -Building construction (floorings) 10. 10 | P a g e PHYSICAL & CHEMICAL PROPERTIES DURABILITY - Durability is the measure of how well asphalt concrete retains its original characteristics when exposed to normal weathering and aging processes. ADHESION AND COHESION - Adhesion is an ability to stick to the aggregate in the paving mixture. Cohesion is the ability to hold the aggregates particles after the pavement is finished. PURITY - Asphalt is composed of almost entirely bitumen, which is soluble in carbon disulfide. Refined asphalt is almost pure bitumen and usually more than 99.5% soluble in carbon disulfide. They are inert if there is impurity present. It can be said that it is free from water once it leaves the refinery. However, the presence of water may cause the asphalt to foam when it is heated above 100C. TEMPERATURE SUSCEPTIBILITY - It becomes harder (vicious) as the temperature decreases and vice versa. This characteristic is known as temperature susceptibility. AGING AND HARDENING - Asphalt hardens in the paving mixture during construction and the pavement itself. The process of oxidation where asphalt combines with oxygen together makes the mixture harder. 11. 11 | P a g e ADVANTAGES WEATHER - Hardening process occurs as the temperature decreases, which makes the asphalt harder. COST - It is cheaper to install than driveways made of concrete. RECYCABLE - Not only can the aggregates be reused but the asphalt cement binder also retaining the cementing properties and reuse again in new mixture. DISADVANTAGES STRENGTH - Asphalt pavement is weaker than concrete pavement. HEAT It becomes softer when it is exposed to hot temperature. The softness will cause the driveway susceptible to the formation of ruts. 12. 12 | P a g e 3C Seacrete Seacrete can be known as Biorock or Seament. It is the end product of electro- accretion / electro-accumulation alike the electroplating which build up an electrified metal frame that is encouraged by calcium carbonate. This process has created man-made distance. The biorock building process is called as accretion and not to be confused with Biorock sewage treatment. The biorock building process produces cement like engineering structures and marine ecosystems. It works by passing small electrical current through electrodes in the water. The structure grows more or less without limit as long as the current flows. . Physical / Chemical properties - Mg(OH)2 (Magnesium hydroxide) - (brucite) Mg(OH)2 + CO2 = MgCO3 + H2O - CaCO3 (Calcium carbonate) - (limestone) Ca++ + 2HCO3- = CaCO3 + H2O + CO2 - Compressive strength from 3720 to 5350 lbf/in (26 to 37MPa) Appropriate Usage / Application: - It can produce mix with construction aggregate. - It can build components in the sea floor or on land. - Produce (Construction material) 13. 13 | P a g e Limestone Brucite - Hydrogen production - Restoring and protecting coral reefs growth. - Mariculture - Sewage treatment Advantage - Grows cement-like engineering structures - Self-growing construction materials - self-repairing - Strong construction material - Constructing new coral reef Disadvantage - Consume lots of time - Need a lot of electricity 14. 14 | P a g e Aesthetical value - It can be decoration materials - It can be construction materials - As artistic structures - Protecting and preserving the marine ecosystems Process The process uses a low-voltage of electrical current through a conductive structure placed on seabed. In addition to reverse the effects of rusting, the electricity creates electrolytic processes which result in precipitation of a stony calcified layer on the metal frame which provides an ideal substrate for the growth of corals. The result is a composite of brucite and limestone with mechanical strength similar to concrete. Derived from seawater, this material is similar to the composition of natural coral reefs and tropical sand beaches. 15. 15 | P a g e 3D- Decorative Concrete i) Definition and usage of decorative concrete Decorative concrete is created through a finishing process that is intended to provide an aesthetic quality. It comes in various colors, patterns and textures. They are applied to create decorative effect that enhance and beautify concrete. It is not just simple a utilitarian medium for construction, it also acts as an aesthetic enhancement. Decorative concrete is a versatile material use in homes for floors, kitchen countertops, patios, driveways and etc. It is also a good option for house owners who want high end look for their homes. Besides that, decorative concrete is also used in commercial and industrial such as in bridges and highways. Decorative concrete is branch out into different types of concrete such as, stamp