ARTIC ASPHALT-RUBBER TECHNOLOGY INFORMATION CENTER BIBLIOGRAPHY OF ARTICLES, REPORTS AND STUDIES

INTERNATIONAL REPORTS

INTERNATIONAL REPORTS: AUSTRALIA PERFORMANCE

AP.1 = RPA_A1105.pdf The Use of Polymer Modified Emulsions in Stress Absorbing Membranes and Seals Holleran, Glynn Emoleun 12 pages This paper describes the use of polymer modified emulsions in construction of stress absorbing membrane interlayers and seals. The microstructure of the polymer additives is discussed in relation to the mechanisms of stress absorption and the advantages of using an emulsion system are illustrated. AP.2 = RPA_A1106.pdf Modification of Paving Asphalts by Digestion with Scrap Rubber Oliver, John W.H. Australian Road Research Board 37 pages The service performance of sprayed surface treatments laid where traffic stressing is severe or where the existing pavement is cracked can be significantly improved if comminuted scrap rubber is digested in the asphaltic cement before spraying. Work has been dome to identify the factors, which are of importance in optimizing asphalt performance. Measurement of the deformation response of the digestions to sinusoidal loading indicated that the modified binder had improved response under the loading produced by traffic at high pavement temperatures and that produced by thermal contraction at low pavement temperatures. A simple and rapid test procedure was developed to measure the response under loading conditions approaching these. The procedure is to subject a prism of the binder at 60C to a shear strain of 1.0 in

creep and then determine the elastic recovery when the stress is removed. The most important factor affecting elastic recovery was found to by the morphology of the rubber particles as determined by the comminution process used in their manufacture. A simple bulk density test was used to characterize this morphology. Digestions of natural (truck tires) rubber are generally superior to those incorporating synthetic (car tire) rubber but are more affected by changes in the time or temperature of digestion. Where a cryogenic comminution process has

been used only digestions of natural rubber particles produced a significant improvement in asphalt properties. Elastic recovery of strain in linearly related to rubber concentration. As rubber particle size decreases elastic recovery of the digestions increases.

INTERNATIONAL REPORTS: AUSTRIA NOISE

AUSN.1 = RPA_A1107.pdf Noise level reduction through SILENT ASPHALT Nievelt, Dr. Gottfried; Stehno, Dr. Gernard; Stickler, Dr. Helmut & Ertl, Johann, Dipl.-Ing. Federal Ministry of Public Works & Technology 1985 95 pages Silent asphalt is an extremely elastic road surface consisting of two layers, which can be put on any portative subconstruction and road surface without joints in thickness of three to eight cm. The examinations carried out on the silent asphalt test road in Angath (A 12, km 14, 5-16, 0) in the course of the research assignment at issue have shown that silent asphalt is a road surface construction featuring essential advantages over customary road pavings. Silent asphalt is a measure reducing traffic noise at its source and is therefore well suited to supplement or replace constructional noise protection measures.

INTERNATIONAL REPORTS: AUSTRIA MICELLANEOUS

AUSM.1 = RPA_A1108.pdf Highlights of Technical Papers Given at Asphalt-Rubber Conference in Graz, Austria March 16, 1988 Nielson, Don L.; Stehno, Gerhard 5 pages This paper includes test data about abatement Other information on the reduction of traffic noise with the use of Asphalt-Rubber.

INTERNATIONAL REPORTS: BELGIUM PERFORMANCE

BP.1 = RPA_A1109.pdf The Use of Rubber Bitumen in Road Construction – Draining Mixes VandeVelde, Hugo Esso, S.A. 23 pages Draining mixes made with rubber bitumen have demonstrated their worth at the various sites where they have been applied since 1981. Their performance and their maintenance of their characteristics and benefits in time demonstrate that this technology can be used on a wider scale in the future.

INTERNATIONAL REPORTS: CANADA PERFORMANCE

CP.1 = RPA_A1110.pdf Scrap Tire Applications in Ontario’s Transportation Industry Kennephol, G.J. Ministry of Transportation, Ontario, Canada April, 1993 37 pages Key Words: scrap tires, pollution, recycling, rubber, polymers, rubber-modified asphalt, pavement Reported are the Ministry‟s efforts in evaluating a whole compendium of opportunities to utilize scrap tire rubber in transportation-related applications. Described are lightweight fill, access hatch transition collars, paving bricks, noise barriers, energy attenuators, ballast for construction markers, portable speed bumps, guiderail block-outs/posts and vehicle protection barriers. The status report also includes two basic research projects to enhance the performance properties of RMA compositions and develop novel products. CP.2 = RPA_A1111.pdf Evaluation of Rubber Modified Asphalt Demonstration Projects Emery, John, Geotechnical Engineering limited Ministry of Transportation, Ontario, Canada February, 1994 205 pages Eleven Ontario Demonstration projects (wet and dry processes) were evaluated in terms of pavement performance, environmental impacts, life cycle costs and recyclability. Conclusions are included on performance where the dry process should produce performance equivalent to conventional hot mix and the wet process appears to enhance performance. Air emission testing showed rubber mixes produce higher MIBK (skin and mucus irritant that is moderately toxic but is not considered to be a carcinogen) but other emissions appeared to be the same as for conventional hot mix. Recyclability appears to be feasible but repeated recycling that reduces rubber effectiveness could cause disposal problems. Life cycle costs of rubber mixes appear to be higher than conventional mixes but sufficient time has not elapsed to monitor long-term performance, which could impact life cycle costs. CP.3 = RPA_A1112.pdf Recycling of Rubber Tires in Asphalt Paving Materials Piggott, M.R. & Woodhams, R.T., University of Toronto, Canada Environmental Protection Service March, 1979 60 pages A relatively small proportion of asphaltic bitumen comprises the average road surface in North America, and yet it is sufficient to consume nearly 75% of the more than 60 billion pounds of bitumen sold annually in Canada and the United States. Although this proportion of asphaltic

binder is small (about 6%) its function is critical to the performance of the road surface. Despite the effort that has gone into developing better road surfacing materials, the quality of asphalt binders has not improved significantly over the last 5,000 years. It has been known for at least 50 years that the addition of rubber to asphalt will produce markedly superior road surfaces, some of which are still in use since they were first laid. Partly because of cost and partly because of nonconventional paving techniques rubber has been largely ignored as a practical additive except in special cases. Today there is a large accumulation of old tires that if ground into a fine powder can be mixed in a conventional pug mill along with sand, crushed stone and hot asphalt to produce a hot mix which can be applied in the normal manner without any specialized knowledge or techniques. The extra cost of such modification is only 1% of a typical paving contract whereas the advantages include lower maintenance costs and a more durable road surface that is likely to last well into the next century. This report, specially prepared for Environment Canada, is designed to assist civic, provincial and federal authorities in the development of improved road surfacing formulations through the reuse of old tires. CP.4 = RPA_A1113.pdf Use of Asphalt Rubber Carrick, J.A. & Davidson, J.K., McAsphalt Industries Limited, Canada; Aurilio, V., Advances Asphalt Technologies, VA, & Emery, J., John Emery Geotechnical Engineering Limited, Canada 1994 20 pages An Assessment of Ontario scrap tire crumb rubber modified hot-mix demonstration projects indicated the wet process can surpass conventional mixes in performance with favourable life-cycle costs. These findings, and development of improved AR mix design procedures and terminal blended AR with minimum storage stability of 24 hours, resulted in three AR projects in 1994. A modified dry process project was also successfully completed using finer CRM (30 mesh). The specific project studied involved resurfacing a pavement in Brantford with two lifts of hot mix incorporating AR. This hot mix was designed, produced, placed and compacted without any problems. During the Marshall mix design, it is important to allow mix conditioning prior to briquette compaction and place a surcharge on the compacted briquette to prevent rebound during cooling. During field compaction, it is necessary to use a soap solution with all rollers and continue finish rolling until the AR mix has cooled. There were no perceived environmental problems. Overall project monitoring involved mix compliance, compaction, smoothness, friction and resilient properties. CP.5 $4.00 Evaluation of Rubber Modified Asphalt Demonstration Projects Emery, John John Emery Geotechnical Engineering Limited Presented at TRB 1994 35 pages Eleven Ontario rubber modified asphalt demonstration projects were evaluated in terms of pavement performance and environmental impacts, including recyclability. On the basis of generally poor short-term performance of eight dry process (rubber modified asphalt concrete) projects, it appears that this method of crumb rubber modifier use should not be pursued

unless there is considerable care in materials selection, mix design, and mix production and placement. This study involved: evaluation of the demonstration projects in terms of materials and pavements factors, and environmental impacts, including recyclability; comparison of the findings to those of other jurisdictions, with identification of technical solutions to any issues; preparation of a summary of technically and cost-effective approaches to foster the use of rubber modified asphalt; and identification of policy and program impediments, with options for resolution. The materials and pavements factors, and economic analysis aspects of the study will be described in some detail, with an indication of the environmental impacts findings. CP.6 = RPA_A1115.pdf Implementing End Result Specifications: QC/QA/ERS/TQM Emery, John John Emery Geotechnical Engineering Limited TRB January, 1995 28 pages Contractors and their suppliers have generally developed the necessary capabilities to meet the new QC sampling, testing and analysis requirements associated with ERS, and without too much trauma. Agency retesting and referee protocols are available to deal with testing issues. The adoption of ERS requires continuing agency-contractor interaction for effective, equitable implementation, and monitoring to ensure that the statistical quality assurance objectives are met. Partnering, as a TQM component, provides an appropriate mechanism for the day-to-day resolution of problems associated with ERS implementation and associated agency QA disputes. Agency-contractor workshops have proven to be an excellent forum to communicate on quality and prepare for new ERS requirements. CP.7 $2.00 Development of Rubber/Asphalt Binders by Depolymerization/Devulcanization of Scrap Tires in Asphalt Kennepohl, G. J., Ministry of Transportation of Ontario, & Zanzotto, L., Univ. of Calgary TRB January, 1996 29 pages Scrap tires in three forms - the crumb rubber 60 minus mesh, crumb rubber 20 minus mesh, and buffed rubber were subjected to depolymerization/ devulcanization by applying heat, high shear and the combination of both. Different reaction temperatures and times of reaction were applied. The reaction products were submitted to the testing of rheological properties by measurement of creep and recovery, viscosity and some conventional test. Amount of unreacted rubber and tendency to separation during the hot storage were also tested. Selected materials were evaluated according to SHRP specification and by the Gel Permeation Chromatography. The results from SHRP testing show that these materials are less temperature sensitive than conventional asphalts prepared from the same crude oil as the base asphalt. These materials were prepared in larger quantities and are presently being tested for their performance in paving mixes.

CP.8 = RPA_A1117.pdf Use of Wastes, Surplus Materials and By-Products in Transportation Construction Mackay, Michael & Emery, John John Emery Geotechnical Engineering Limited October, 1993 17 pages It has only been possible to give a brief overview of the current and potential reuse and recycling of the fourteen wastes and byproducts of greatest interest for aggregate and cementitious applications in construction. There is obviously much scope for the cost-effective, technically sound use of wastes in pavement construction with resulting materials, energy and landfill conservation. CP.9 = RPA_A1118.pdf Use of Rubber-Modified Asphalt in Cold Regions Takallou, H.B. & Hicks, R.G., Oregon State Univ., & Esch, D.C., Alaska DOT OSU/Alaska DOT Presented at Workshop on Paving in Cold Areas in Ottawa, Ontario, Canada April, 1987 31 pages Rubber-modified asphalt pavements have been used in Sweden and the United States since the 1970‟s. In these applications the ground recycled tire rubber particles (1/4 in. minus) are added to a gap-graded aggregate and then mixed with hot asphalt cement. The resultant paving mixture has been reported to have the following characteristics for cold regions: 1) Improved resistance to load-induced tensile cracking and to low temperature cracking. 2) Improved skid resistance under icy conditions. 3) Good resistance to studded tires and/or chains. 4) Reduced tire noise levels. Disadvantages include higher initial costs due to the rubber costs, the increased asphalt content required, and the unusual aggregate grading. However, these tend to be offset by the improved performance. CP.10 = RPA_A1119.pdf 1988 Report on Bridge Deck Waterproofing Evers, R.C. & Lynch, D.F. 13 pages In 1988, the Ministry of Transportation monitored the thickness of waterproofing membrane placed on bridges under its authority, as well as the quality of the membrane. Membrane thickness is controlled by an end result specification (ERS) that was introduced in 1986. This specification was expanded in 1987 to include membrane quality. This report contains a summary of the data assembled and comments on the level of compliance with specified tolerances. Comparison is also made to data of previous years. As a result of an analysis of the contained data, it is concluded that membrane thickness and quality compliance is continuing to improve under end result specifications.

CP.11 = RPA_A1120.pdf Sealing Cracks In Asphaltic Concrete Pavements Evers, Ronald C. & Lynch, Daniel F. Ontario Ministry of Transportation & Communications 45 pages In 1980 the Ministry of Transportation and Communications of Ontario embarked on a programme of field trials to identify the most suitable materials for sealing asphalt pavement cracks. The trials were subsequently expanded in 1982 to identify the most appropriate methods. This work has led to three additional materials being approved for use in asphalt pavements and the extensive use of hot compressed air and overband sealing. CP.12 = RPA_A1121.pdf Stress Absorbing Membrane Interlayer (SAMI) Cooper, J.A.; Lynch, D.F. & Aquin, R.C. Ontario Ministry of Transportation & Communications April, 1983 44 pages This report describes the application of a SAMI, in May of 1982, onto a badly cracked concrete pavement that was constructed in 1967 on King‟s Highway 77. A brief description of blending, application and construction procedures is included as well as observations regarding performance. CP.13 = RPA_A1122.pdf Hot-Mix Trials with Polymer Asphalt Cement – A Construction Report (1987, 1988) Evers, R.C. & Lynch, D.F. Ontario Ministry of Transportation & Communications January, 1989 18 pages Polymer modified asphalt cements are claimed to produce more durable hot-mix pavements. The Ontario Ministry of Transportation constructed four trials using a proprietary polymer modified asphalt cement called “Styrelf” to establish the mixing, handling, laying, compaction and long term performance relative to control mixes on the same project. This report contains the location of the trials, mix design data, observations at time of construction and the visual appraisal of two trials after one winter in service. It is anticipated that it will take at least five years of annual monitoring before any conclusions on relative performance can be made. CP.14 = $6.00 Experimental Hot Mix Pavements with Scrap Tire Rubber at Thamesville, Ontario The Ministry of Transportation, Ontario, Canada Ministry of Transportation & Ministry of the Environment, Ontario, Canada 1989 64 pages

The purpose of the demonstration was to confirm that (a) the construction of asphalt rubber hot mix pavements is environmentally acceptable and complies with worker health and safety regulations; (b) asphalt rubber pavements can be recycled in both the plant mix and in-place modes; and (c) asphalt rubber pavements provide equivalent performance to standard pavements. CP.15 = RPA_A1124.pdf Performance of Scrap Tire Rubber Modified Asphalt Paving Mixes Coomarasamy, A., Ministry of Transportation, Ontario, Canada, & Hesp, S.A.M., Queen‟s University, Ontario, Canada Ministry of Transportation/Queen‟s Univ. 1997 17 pages Although scrap tire rubber has been used for asphalt modification for several years, the most effective way of utilizing scrap tire rubber for this application has not been thoroughly investigated. There is a need to determine the most suitable types (including the particle size) of the tire crumb rubber, which would give the best performance. Tire rubber modified asphalt binders were prepared by mixing (under moderate shear) 30 and 80 mesh crumb rubber and partially devulcanized tire rubber, with two grades of paving asphalts. High shear mixing was used only to prepare a sample containing a fine dispersion of crumb rubber particles of 0.4 microns, from a 30 mesh crumb rubber and asphalt. Low temperature fracture toughness testing was performed using a new method based on ASTM E 399-90 Procedure, at –20 degree Celsius. SHRP binder tests for high-temperature and low-temperature performance rating, were also performed. Rutting tests were conducted on a wheel-tracking machine, at 60-degree Celsius and the resistance to low temperature cracking was determined by thermal restrained specimen test (TSRST). The results reveal that the high temperature performance of modified asphalt systems containing fine crumb rubber particles is significantly better when compared to the performance of the other samples. Moderate improvements in low temperature thermal cracking resistance was also achieved with these systems. CP.16 = RPA_A1125.pdf Saskatchewan Asphalt Rubber Report Scott, John L.M. Ground Engineering, Ltd. 1987 15 pages As per your verbal communication on June 25, 1987 concerning the above, you stated that you would be unable to undertake the tour with me, but you would like a summary report covering location, year constructed, type of construction, etc., as quoted in my proposal. CP.17 = RPA_A1126.pdf Performance Monitoring of Rubber Modified Asphalt Demonstration Projects John Emery Geotechnical Engineering Limited November, 1997 242 pages

In 1996 and 1997, a program of detailed performance monitoring (consisting of visual inspections, distress surveys, deflection and frictional properties testing, and pavement profile measurements) of twelve rubber-modified asphalt (RMA) pavement projects completed in Ontario was conducted by John Emery Geotechnical Engineering Limited, Consulting Engineers (JEGEL) on behalf of the Ontario Ministry of Environment (MOE). Visual inspections only were completed for an additional twelve projects that were constructed in 1993. The purpose of this performance monitoring was to assess the Ontario RMA projects and compare their performance with conventional pavements and each other to determine the performance benefits attributable to the various RMA technologies, and provide recommendations for future RMA pavements in Ontario. While it is still relatively early in the life of the RMA demonstration sites, it is clear that „dry process‟ RMA sections are deteriorating at a faster rate that conventional asphalt pavements and „wet process‟ asphalt rubber (AR) sections. Recent „moist process‟ RMA trials constructed using finer crumb rubber modifier are performing better than the dry process sections and comparably to conventional pavement. Terminal blend AR sections are performing similar to or slightly better than conventional pavements. All of the RMA processes appear, at this relatively early point in the pavement life, to be significantly more costly than conventional pavements; extension of the current monitoring program will assist in substantiating the relative performance benefits for RMA life cycle costing. CP.18 = RPA_A1127.pdf Five Years with Rubber Asphalt Seals Scott, Saskatchewan Highways & Transportation 9 pages (pages 193 to 201) The technology of rubber asphalt seals, developed for Saskatchewan is unique in North America and has resulted from sustained effort. The quality of the product and the success rate in long term performance have improved each year. Once the problem of centreline stone loss has been overcome, the product will be a very acceptable medium cost surface treatment. CP.19 $4.00 Rubber Asphalt Seal Coats Scott, Saskatchewan Highways & Transportation 1979 35 pages During the summer of 1978, eight test sections were constructed to evaluate seal coats using rubber asphalt as binder membrane and graded aggregate as the protective cover. The evaluation was considered necessary to determine whether low cost cold mix and current seal coat surfaces could be replaced successfully and economically by this method of construction. The rubber asphalt was prepared by mixing and heating 25% vulcanized rubber crumb with 75% Saskatchewan AC 6 asphalt cement. The aggregate used was produced by crushing glacial origin gravels. Except for limiting sand and clay sizes, no washing or further processing was done. A description is given of early lavoratory studies and field experiments, the test section sites chosen, construction and equipment problems experiences, initial evaluation and economic analysis.

Each test section represented a typical surface type and condition which included primed subgrade, cold mix on subgrade, primed granular base course, asphaltic concrete on granular base and full depth asphaltic concrete. The initial evaluation showed that stone retention is mainly a function of asphalt binder application rate with approximately 2.73 L/m2 (at 15C) required for 16mm maximum aggregate. Studies also indicated that the graded

aggregate specification requiring 35% stone and no more than 6% 71M size was satisfactory. Economic analysis showed that the use of four asphalt distributors and all construction done by Department forces, costs per kilometer for a standard 7.3M traveled way could be reduced to $5,000. CP.20 = RPA_A1129.pdf Report On Use of Rubber Crumb from Waste Rubber Tires in Highway Construction Heiman, G.H. Saskatchewan Highways & Transportation September, 1980 32 pages The disposal problems of one million used car and truck tires in the Providence of Saskatchewan encouraged the Department of Highways to pursue some known uses of rubber crumb. The use of rubber asphalt was developed in Phoenix by C.H. McDonald and used successfully as a seal coat binder. The department had to verify the process could work in cold climates and compare economically with out established processes. The evaluation stage of the rubber asphalt binder is in progress and will continue. The process has shown enough promise and potential that this report can be written to show that the department should continue to sue rubber asphalt binders. This continued use would provide the Department of Industry and Commerce with a commitment on the quantity of used tire crumb Highways can use annually. This quantity should enable a decision to be made about a rubber grinding plant in Saskatchewan. This report will review the history and uses of recycled tires in highway construction, the economics of using rubber asphalt binders, and recommend how the department should proceed to use rubber asphalt binders. (RAS). CP.21 = RPA_A1130.pdf Trial Sections with Polymer-Modified Asphalts on Highway 400 Joseph, P.E. & Kennepohl, G.J. Ministry of Transportation June, 1991 40 pages Key Words: asphalt, mix design, additives In July, 1990, the ministry of Transportation of Ontario built trial sections on Highway 400, near Innisfil, to compare standard and modified HL 1 mixes in terms of their effectiveness to resist rutting and low temperature cracking. In addition to Premium Asphalt from Petro-Canada, the additives used for the trial sections include Novophalt, Neoprene, Vestoplast, and tire rubber, which had not been evaluated previously by the MTO. The selected test site represents a typical highway section in a colder environment experiencing heavy traffic induced rutting. The mix design for the trial sections was modified to yield results in 2-5 years.

CP.22 = RPA_A1131.pdf Low Temperature Performance of Scrap Tire Rubber Modified Asphalt Concrete Hesp, Simon, Queen‟s University Ontario Ministry of Transportation 23 pages The low temperature performance of rubber-modified asphalt concrete systems was investigated through thermal stress restrained speciment tests. Low temperature TSRST tests on surface grafted, regular crumb rubber-modified and unmodified asphalt concrete mixes yielded similar results. The small improvement for the rubber-modified systems can be attributed to a reduction in the stiffness of the binder. The failure temperature for a mix prepared according to the wet process with 1% extra binder was an impressive 15-degree colder than the control. The improvement is mainly due to the high binder content and a resulting lower stiffness. The addition of 20-wt %40 mesh rubber to the binder in an SMA design did reduce the fracture temperature but the effect was not as large as for the wet process. Partial devulcanization or disintegration of crumb rubber in hot asphalt binders utilizing high shear and heat can produce finely dispersed rubber-asphalt systems with improved high temperature performance. The devulcanization or disintegration process should also be environmentally friendly and it should not oxidize the binder. CP.23 = RPA_A1132.pdf Summary Report: Rubber Modified Asphalt Pavement Project, Main Street, Birch Street to Power Plant Emery, John, Geotechnical Engineering Limited Ministry of Environment and Energy December, 1994 56 pages In September 1994, the Corporation of the Town of Kirkland Lake in conjunction with the Ontario Ministry of Environment and Energy constructed a demonstration project with rubber modified hot-mix asphalt concrete as part of the Waste Reduction Office Scrap Tire Project. The primary objectives of the trial are to assess the performance of the MRUAC mix and to evaluate the use of the modified process. The demonstration project was constructed without any significant problems and is considered to be successful in all aspects of the work. While emissions test was not involved, there were no perceived environmental problems with MRUAC process. The cost of the MRUAC mix for the trial is in the order of 20 percent higher than conventional mix in the area. Ultimately, the long-term performance of this section of pavement will reveal whether the process is cost effective and a viable alternative for adding crumb rubber modifier to hot-mix asphalt. CP.24 = RPA_A1133.pdf Summary Report: Asphalt Rubber Demonstration Project Emery, John, Geotechnical Engineering Limited December, 1994 61 pages

The corporation of the City of Brantford, in conjunction with the Ontario Ministry of Environment and Energy, constructed a rubber modified asphalt demonstration project in October, 1994. This project was carried out as part of the ongoing MOEE Scrap Tire Project in accordance with the Experimental Plan for 1994 established jointly by the MOEE and the Ontario Ministry of Transportation. The purpose of the project was to evaluate the use of crumb rubber modified asphalt cement binder in dense graded hot-mix asphalt. The project involved resurfacing a 500 m section of Park Road North from Dunsdon Street to Powerline Road with two lifts of hot –mix asphalt incorporating asphalt rubber binder. CP.25 $2.00 Improved Hot Mix Asphalts Containing Reclaimed Rubber Piggott, M.R.; NG, W.; George, J.D. & Woodhams, R.T., University of Toronto Metro Toronto Roads Dept. 1977 8 pages Tests have been carried out to determine the extent of the interaction between asphalt cement and reclaimed rubber from used tires, and also the void content and the Marshall flow and stability of hot mix asphalts made therefrom, In addition the flexural properties of rubber-asphalt concrete slabs have been determined, and sections of road have been laid with these materials. Viscosity measurements suggested that there was very little interaction between reclaimed rubber and asphalt cement at 200, whether the rubber were devulcanized or not. However, the presence of little more than 1 percent of rubber in the hot mix asphalt markedly increased the void content and reduced the stability of Marshall specimens. CP.26 = RPA_A1135.pdf Rubber Asphalt Binders used in Saskatchewan, Canada Heiman, G.H. Ministry of Transportation May, 1980 10 pages Saskatchewan Highway Materials Engineers have been interested in low temperature behavior of asphalts a long time. The correlation of asphalt temperature susceptibility has been recorded by Saskatchewan authors. The interest in low temperature performance of asphalt and the increasing use of seal coats lead naturally into the use of rubber in asphalt. The staff attendance of a rubber- asphalt conference in 1971 in Phoenix caused an in-house test section to be designed and constructed in 1975. This test section was also constructed to see if rubber crumb could be utilized if the province was to grind rubber tires because of the environmental problems tires create in sanitary landfills. CP.27 = RPA_A1136.pdf Central Lab Evaluation of Ecoflex Asphalt Cement Langlois, Pierre; Leclere, Anne-Marie & Moreux, Jean-Claude Quebec DOT March, 1993 12 pages

This report summarizes the results of the different stages of analysis to which a new product must be submitted in the context of a complete assessment. Ecofles asphalt samples were provided by Bitumar and were characterized by the current road binders tests, as well as by a preliminary, but more thorough, chemical analysis. The Second stage of testing, laboratory mixes with Ecofles, was effected simultaneously with the third stage, i.e. the construction of test sections. Therefore laboratory performance results can now be compared with road mixes. CP.28 = RPA_A1137.pdf Toronto Experience with Rubber-Asphalts Piggott, M.R.; George, J.D. & Woodhams, R.T. Univ. of Toronto/ Metro Toronto Roads Dept. May, 1980 12 pages A major research program has been carried out at the University of Roronto concurrently with a paving program by Metro Toronto Roads Dept. These combined efforts have demonstrated the feasibility and usefulness of adding ground tire rubber to hot mix asphalts. CP.29 = RPA_A1138.pdf Rubber Asphalt Seal McInnes, D.; Macleod, Al 1980 41 pages This report is assembled with the intention of achieving the following objectives:

1) To have a single complete set of information on the 1980 R.A.S. Program. 2) To form a basis for comparison of future years work. 3) To aide in the ability to properly analyze 1980 costs.

CP.30 $2.00 Development of Rubber & Asphalt Binders by Depolymerization & Devulcanization of Scrap Tires in Asphalt Zanzotto, Ludo, Univ. of Calgary, Alberta, Canada & Gerhard J. Kennepohl, Ministry of Transportation of Toronto, Ontario, Canada 1996 8 pages Scrap tires in three forms – crumb rubber 60 minus mesh, crumb rubber 20 minus mesh, and buffed rubber – were subjected to depolymerization and Devulcanization by applying heat, high shear, and a combination of both. Different reaction temperatures and times of reaction were applied. The reaction products were submitted to the testing of rheological properties by measurement of creep and recovery, viscosity, and some conventional tests. The amount of unreacted rubber and tendency to separation during the hot storage were also tested. Selected materials were evaluated according to SHRP specification and by the gel permeation chromatography. The results from the SHRP testing indicate that these materials are less temperature sensitive than conventional asphalts prepared form the same crude oil as the base

asphalt. These materials were prepared in larger quantities and are being tested for their performance in paving mixes.

INTERNATIONAL REPORTS: FRANCE PERFORMANCE

FRAP.1 = RPA_A1140.pdf Great Innovation with a Process of Hot In Place Recycling with Silted Porous Asphalt Concrete Implemented on the A1 Motorway in the North of France in 1984 and 1985 Sainton, Alain Beugnet Group 3 pages Brief report on the hot mix place recycling of an asphalt rubber hot mix. FRAP.2 = RPA_A1141.pdf Open-Graded and Dense Graded Mixes With Asphalt-Rubber ESSO Beugnet 1984 42 pages Reports on the results of modulus, dynamic creep and fatigue testing performed on open graded mixes using asphalt rubber and asphalt cement, and dense graded mixes using asphalt rubber, asphalt cement, and a CRM added dry. FRAP.3 = RPA_A1142.pdf A Revolution in Asphalt-Rubber Binders: Flexochape Storable Binder Sainton, Slain, Beugnet Group 1989 16 pages The discovery of storable FLEXOCHAPE binder is particularly important for the development of asphalt rubber concrete (ARC). They provide:

- A marked softness for field application, - The possibility to cover small jobs with a few hundred tons of ARC, - Substantial cost efficiencies due to the slight reduction of the amount of binder from 0.2

to 0.4 % depending on high or low viscosity. FRAP.4 = RPA_A1143.pdf In-Situ Pavement Retreading with A.R.C. 600 Guerin, Michel French Republic-Ministry of Equipment, Housing, Land Development, and Transportation September, 1987 5 pages The in-situ pavement retread process consists in recreating, from a damaged pavement unsuited to usual traffic, an homogenous and stable structure. Existing materials are therefore retreaded in-situ with a binder and possibly complementary materials in order to obtain a new road base or sub-base. Retreading makes it possible to restore the pavement bearing capacity

and profile while limiting the need for “fresh” aggregate and modifying geometrical characteristics as little as possible. FRAP.5 = RPA_A1144.pdf The Road Retread Process with A.R.C. 600 Sainton, Alain Beugnet Company September, 1987 4 pages In-situ retreading with a machine of the ARC 600 type is well adjusted to moderate traffic roads when the retreaded course is used as road base. In the case of roads with heavy traffic, the retreaded course will be an excellent sub-base. Economic results are very advantageous compared to those obtained with traditional techniques (aggregate processed with hydraulic binders). Thanks to ARC 600, important savings in materials and their transport are achieved; it is a particularly interesting process when pavement level problems occur. FRAP.6 = RPA_A1145.pdf Development of New Products and Technologies: A European Contractor’s Experience Coroller, Alain LE Colas S.A. September, 1987 4 pages Surface Dressings are executed using two main families of binder. For decades, road research laboratories have tried to develop a binder which would combine the advantages of both families. In 1979, we initiated a comprehensive research program that extended over 3 years, involving tests carried out on several hundred chemicals during 10,00 hours spent by engineers and specialists, before we executed the first trial on roads. The results were beyond our hopes, because on one hand, this new process provides a better workability than the less viscous cut backs during the first 2 hours, which is favorable to a proper embedding of the chippings.

INTERNATIONAL REPORTS: FRANCE RECYCLABILITY

FRAR.1 = RPA_A1146.pdf An Innovative Process for On-Site Hot Recycling of Six-Year-Old Open-Graded Mixes Fourtier, Stephanie, SANEF, & Sainton, Alain, BUEGNET SANEF/BEUGNET *Also under Industry Recyclability 14 pages The A1 Autoroute connecting Paris with Northern Europe is one of the most heavily traffic roads carrying an average of 40,000 vehicles per day, 30% of which are trucks. In the early 1980‟s, during rainy weather, truck traffic had become such a problem that the highway authority, and SCETAUROUTE Nord, its construction division, began to evaluate ways to address safety hazards of bad weather. A test was implemented on a particularly troublesome section of the roadway around Compiegne by resurfacing with a pervious overlay; based on laboratory data as well as field experience, the pervious overlay was an asphalt-rubber open-graded mix (DRAINOCHAPE) developed by BEUGNET.

INTERNATIONAL REPORTS: GERMANY NOISE

GN.1 = RPA_A1147.pdf Silent Asphalt 4 pages Bitumen with highly elastomeric additives belongs to the so-called “second generation” of bonding materials-bitumens, which have been modified with the help of denied additives in order to improve certain characteristics of the bitumen. This modified binder consists of three components: 1) BITUMEN 2) AROMATIC OIL

To flux the bitumen and allow it to react with the additives 3) HIGHLY ELASTOMERIC ADDITIVES

INTERNATIONAL REPORTS: THE NETHERLANDS NOISE

NN.1 = RPA_A1148.pdf A Noise-Absorbing Road Surface made of Poroelastic Asphaltic Concrete Dr. ing. A. von Meier & Ir. J.C.P. Heerkens January, 1986 114 pages A new road-surface material, called poroelastic asphaltic concrete (PEAC), has been designed with a view to its acoustic properties. The aim was to achieve the greatest possible sound absorption in the frequency ranges that are most important as regards traffic noise as well as good civil engineering properties. The material is an open-textured asphalt mixture with a very high voids percentage made possible by the addition of rubberized bitumen as a binder. The rubberized bitumen contains finely ground old tyre tread. On a wearing course of 4 cm on a provincial road, with an average measured speed of about 80 km per hour, a noise reduction of about 3-5 dB was achieved relative to noise levels on dense asphaltic concrete. Besides reducing traffic noise at the source, the use of this material also contributes to improving road safety and to solving the problem of getting rid of old tyres. PEAC can be used on a large scale, employing technology already available in the road-building industry.

INTERNATIONAL REPORTS: THE NETHERLANDS PERFORMANCE

NP.1 RPA_A1149.pdf The Application of Rubberbitumen in The Netherlands (includes the Scrap Tire Utilization in the US and Europe) Heerkens, Ir. J. & Jonker, Ir. C., Road Construction Co., J. Heijmans B.V., Rosmalen European Asphalt Magazine March, 1993 14 pages Recently publications came out about the increasing pressure exerted by the government in USA to apply rubber from scrap car tyres in road construction. Regulations indicate that reclaimed rubber must be processed as a component in asphalt, either by adding it to the bitumen beforehand, or by adding it to the asphalt hot mix. This is done with the object of getting rid of the large amount of car tyres becoming available every year. NP.2 = RPA_A1150.pdf Effects of Stress Absorbing Membrane Interlayers Molenaar, A.A.A., Netherlands Pavement Consultants: Heerkens, J.C.P., Contracting Co. J. Heijmans B.V. & Verhoeven, J.H.M., Delft Univ. of Technology 1986 46 pages This paper will deal with the effect of stress absorbing membrane interlayers for the reduction of reflection cracking. NP.3 = RPA_A1151.pdf Open Graded Rubberized Asphalt for Traffic Noise Reduction in Urban Areas Heerkens, J.C.P., I.R., J. Heijmans B.V. & Von Meier, I.R.A., Dr., M + P Acoustic Consultants Wegenboumaatschppij J. Heijmans B.V. 13 pages This paper deals with the development of open graded asphalt for traffic noise reduction in urban areas. In urban traffic the rolling noise is of little importance, but the propulsion noise becomes dominant. This has a great impact, especially on the lower frequencies. A mix is developed, based on only crushed aggregate with sizes 4 to 8 mm and filler. In order to comply with the requirements of mechanical stability and durability a rubberized bitumen has been used.

INTERNATIONAL REPORTS: THE NETHERLANDS MISCELLANEOUS

NM.1 = RPA_A1152.pdf Ontwikkeling van een mengselontwerpmethode voor de regenatie van oud rubberasfalt Einglish translation: Development of a mixture design method for the regeneration of old rubber asphalt Stas, W.F.; Bochove, G.G. & Wegenbouwmaatschappij, J. Heijmans B.V. April 25, 1994 81 pages This report is written in Dutch, no summary available.

INTERNATIONAL REPORTS: PORTUGAL PERFORMANCE

PORP.1 = RPA_A1153.pdf Prediction of Existing Reflective Cracking Potential of Flexible Pavements Pais, Jorge & Perceira, Paulo, University of Minho 9 pages The overlay of a cracked pavement is subject to reflective cracking due the existing crack potential. In a cracked pavement, this cracking potential can be evaluated by beans of the crack activity due to traffic loads and the temperature gradient. In this work, the crack activity was measured with a Crack Activity Meter on 14 test sections of Portuguese flexible pavements. The resulting crack activities were analyzed and the influence of pavement conditions was evaluated, which in turn lead to the development of a model to predict crack activity before overlay. PORP.2 = RPA_A1154.pdf Evaluation of Reflective Cracking Resistance in Bituminous Mixtures Pais, Jorge & Pereira, Paulo, University of Minho 10 pages Bituminous overlays are currently the most prevalent method used to retard the reappearance of cracks in the pavement surface. Even though the usual distress mode in overlays is reflective cracking, the design of these overlays typically does not take this particular distress mechanism into account. Oftentimes, reflective cracks rapidly propagate through the overlay, sometimes within a year or two of rehabilitation. Ideally, overlays should have the ability to retard, for some time, the propagation of the existing crack pattern. In this paper, laboratory simulation of the cracking phenomena that takes place in the field is carried out with the reflective cracking device (RCD). The RCD applies a typical crack activity pattern as can be directly measured in flexible pavements. PORP.3 = RPA_A1155.pdf Mode of Loading in Reflective and Flexural Fatigue Cracking- A Numeric Evaluation Sousa, Jorge; Pais, Jorge & Stubstad, Dick Consulpav International/Univ. of Minho 11 pages Consulpav International is working closely with the University of Minho in Portugal under a contract from the RPA to develop a mechanistic procedure for overlay design that directly take into account the mechanism of reflective cracking as well as classical flexural fatigue cracking. The problem of properly modeling the mechanism of reflective cracking is particularly prevalent in thin asphalt concrete overlays. This paper presents a numerical evaluation, through a finite element simulation, of mode of loading or several types of flexible pavements and overlays placed on these pavements. PORP.4 = RPA_A1156.pdf Feasibility of Using Crumb Rubber Modifier in Hot-Mix Asphalt Pavement Applications in Puerto Rico

Colucci, Dr. Benjamin & Prieto, Jorge Puerto Rico Highway & Transportation Authority March 1994 182 pages This report presents the findings of a study to assess the feasibility of using crumb rubber modifier (CRM) in hot-mix asphalt (HMA) pavement applications in Puerto Rico, as required by Section 1038 (d) of the 1991 Intermodal Surface Transportation Efficiency Act (ISTEA). The study was undertaken at the request of the DOT and Public Works, with the join support of the Puerto Rico Transportation Technology Transfer center. Early in the course of this study, the investigators found that CRM utilization in HMA pavement applications is inextricably linked to the problem of scrap tire recycling.

INTERNATIONAL REPORTS: SAUDI ARABIA PERFORMANCE

SAP.1 = RPA_A1157.pdf Polymer Modified Bitumen: Laboratory Evaluation, Construction Guidelines and Field Experience King, Gayle N. & King, Helen W. Elf Asphalt, Inc. February, 1988 20 pages The abundance of asphalt compatible polymers now available makes it possible to improve almost every aspect of paving. It is crucial, however, that the various physical characteristics, construction constraints, and ultimate cost-benefits be understood. To this end, numerous standards for quality testing and specification are under development. Comparative polymer modified bitumen trials are currently being planned and executed in many states. Recently polymers have been used for dense- and open-graded hot mix, hot and cold recycling, hot applied and emulsion surface treatments, stress absorbing membranes, slurry seals, joint sealants, and patching materials. Increased durability, improved rutting resistance, better aggregate adhesion, improved stiffness moduli, and better overall flexibility are the most beneficial characteristics of polymer modified bitumen.

INTERNATIONAL REPORTS: SOUTH AFRICA PERFORMANCE

SAFP.1 = RPA_A1158.pdf Considerations in the Design of Overlay Pavement to Minimize Reflection Cracking Coetzee, N.F. & Monosmith, C.L. University of Matal, Durban, South Africa 1979 14 pages This paper presents the results of a study directed toward the solution of the reflection cracking problem in overlaid cracked pavements. Stresses in the overlay pavement near the existing crack are estimated using a recently developed finite element program for the pavement system idealization. Crack tip stresses for both traffic leading and temperature changes are calculated; the influence of a stress absorbing membrane interlayer (SAMI) on these stresses is examined and compared with the case for the overlay placed directly on the cracked pavement. SAFP.2 = RPA_A1159.pdf A Review of the Road Performance of A Modified Binder in Southern Africa Over A Six-Year Period Renshaw, R.H., Tosas (Pty) Ltd.; Strauss, Dr. P.J., Bruinette, Kruger & Statberg, & Kleyn, E.G., Trausval Roads Dept. 8 pages Arm-R-Shield bitumen-rubber was first introduced to South Africa in late 1982. This concept was radical in respect of the type of product, its manufacture and the very high application rates at which it was spray applied. Technical as well as application data from the USA was based on empirical information. Test methods as well as what characteristics of the binder were important had to be established. Of prime importance was the correlation of laboratory test data and the actual performance of the binder on the road. This paper reviews various full-scale usage of the modified binder in various climatic areas of the RSA and their performance to date. Specification limits are suggested in respect of resiliency, spray temperatures, flow, softening point and viscosity. Binder characteristics are also classified in order of importance for the optimum performance of roads with a reflection crack problem. SAFP.3 = RPA_A1160.pdf Test Methods for Bitumen/Rubber Used in Seals South African Bitumen and Tar Association 1992 17 pages The technical committee on Bitumen-Rubber, founded in May 1983 under the chairmanship of the Southern African Bitumen and Tar Association, has made steady progress towards developing an end result type specification for this product. A prerequisite to such a specification is the formulation of relevant properties and appropriate test methods. This task was undertaken by a Sub-Committee on Specifications and Test Methods. Although the scope of the a main committee was broadened in February 1987 to embrace all modified bituminous binders, with a consequent change of name to Technical Committee on Modified Binders, it was

desirable that test methods related to specifications for bitumen-rubber be addressed in the first instance. It should be noted that the methods given in this manual cover special tests on modified binders and their constituents only. SAFP.4 = RPA_A1161.pdf A Review of the Road Performance of Bitumen-Rubber in South and Southern Africa Renshaw, R.H., Tosas (PTY) Ltd. 1989 11 pages This paper will review the experience gained from the use of bitumen (asphalt)-rubber I South Africa and states in Southern Africa (Swaziland and Botswana) over a 5 - 7 year period. The Arm-R-Shield of Arizona Refining of Phoenix, Arizona was first introduced to South Africa in October 1982, followed nine months later by a locally developed technology based on an Australian method. The Sahuaro technology was introduced later. The main reason for the introduction of bitumen-rubber was to successfully deal with or entirely eliminate the problem of reflection cracking. This paper will deal with the important issue of the correlation of laboratory test data and binder performance on the road. Specification limits are suggested based on the testing of approximately 1 600-field samples. Limits cover resiliency, spray temperature, flow, softening point, and site viscosity. Binder characteristics are also classified in order of importance for the optimum performance of roads with a crack reflection problem. The paper will also discuss road sections laid in South Africa to evaluate solutions to the crack reflection problem. A jointed concrete pavement was successfully overlayed using bitumen-rubber. The basis for evaluating the old pavement was relative vertical movement at the joints. Developments from the introduction of bitumen-rubber were the design and manufacture of the Crack-Activity-Mater (the CAM), and the use of the Sliding Plate Rheometer to identify effects of various mix variables and a rational design method for bitumen-rubber seals. SAFP.5 = RPA_A1162.pdf HVS Evaluation of Proposed Rehabilitation Measures for the Warden-Villiers Section of National Route N3 Kekwick, S.V. National Institute for Transport & Road Research 12 pages Four test sections consisting of: (1) a rubber-modified asphalt on asphalt-rubber interlayer; (2) rubber modified asphalt; (3) semi gap-graded asphalt on asphalt-rubber interlayer; and (4) asphalt-rubber surface treatment were constructed on an existing road with extensive cracking. These test sections were evaluated using a Heavy Vehicle Simulator (HVS) at elevated, ambient and cooled temperatures. The elevated temperatures, between 34 and 45 C were obtained by radiant heat electric heaters. Cooling of the test sections was affected by shading and by maintaining a flow of water across the sections. Rut measurements were used to evaluate the performance of the test sections. SAFP.6 = RPA_A1163.pdf Load-Associated Crack Movement in Road Pavements Rust, F.C.

National Institute for Transport & Road Research, CSIR 10 pages Reports on the results of crack movement under traffic as measured using a crack activity meter (CAM) under traffic loading. The CAM is attached to the pavement using a quick epoxy and measures horizontal and vertical crack movements using LVDTs. A formula to determine total crack movement is included. No test data is provided. SAFP.7 $2.00 Some Properties of Bitumen-Rubber Asphalt and Binders Hugo, F. & Nachenius, R., University of Stellenbosch 14 pages Since its first introduction to South Africa bitumen-rubber has found increasing acceptance in various rehabilitation projects. This material has been used successfully in the prevention of reflection cracking on cracked asphalt and concrete pavements. Although bitumen-rubber has to date been used mainly in stress-absorbing membrane single seals, the use of rubber in asphalt mixes has gained growing acceptance. The study was conducted in conjunction with a rehabilitation project on the N2 Freeway between Cape Town and Somerset West, which was completed in November 1986. This project included a 40-mm bitumen-rubber asphalt overlay. SAFP.8 = RPA_A1165.pdf Monitoring of Bitumen-Rubber Applications Van Assen, E.J. Hattingh, M.M. & Maccarron, C. National Institute for Transport and Road Research 9 pages Bitumen-rubber is a mixture of bitumen, granulated rubber reclaimed from old vehicle tires and additives such as extender oils and/or diluents. The product can either manufactured on site in the distributor or in a conveniently situated plant near the site. Basically the process consists of the addition of a specified quantity of rubber to hot bitumen of the specified grade. The resultant reacted bitumen-rubber mixture has radically different properties form those of the original components. It has unique elastic, plastic and thermal properties and adheres well to aggregates and road surfaces. These properties make the product very suitable for maintenance and rehabilitation. SAFP.9 = RPA_A1166.pdf Bitumen Rubber Asphalt (Dry Process) Bergh, A.O.; Thompson, H.C. & Nel, A. 3 pages This paper describes the “Dry” process of manufacturing Bitumen Rubber Asphalt, the process of laying the asphalt in the field, the tests required for designing and controlling the mixes and general comments of advantages and field performance of the bitumen rubber asphalt laid over the past four years.

SAFP.10 = RPA_A1167.pdf Technical Guidelines: Construction of Bitumen Rubber Seals SA Bitumen & Tar Association 1990 9 pages This document comprises recommendations on materials and methods of construction for surface treatments in which a bitumen-rubber binder is used. It includes, in particular, recommendations on the bitumen and the rubber to be used, on the preparation and properties of the bitumen-rubber blends and on their handling and storage during construction. SAFP.11 = RPA_A1168.pdf Bitumen-Rubber ITS Introduction and Development in South Africa Renshaw, R.H. 14 pages The bitumen-rubber was brought to the attention of Sastech and Tosas in May 1981 during discussion with Arizona DOT in Phoenix, Arizona. Confidential discussions were held with Transvaal Roads Department and the Department of Land Transport. The object of these discussions were top ascertain from these road authorities if this discussions were to ascertain from these road authorities if this technology had a place in South Africa. The reaction was positive with the comment that “provided the product had a good road performance history over a reasonable period of time” it would be acceptable and would be judged on its performance on South African roads. SAFP.12 = RPA_A1169.pdf Roadmix’ Experience in Bitumen-Rubber Watson, M.J. & Davidson L.K. ROADMIX 14 pages This report provides information that bitumen-rubber compounds can be used very effectively for the rehabilitation of roads and for surfacing new works. They have been developed as an alternative to overlay and reconstruction, and used properly in this context, can be extremely cost effective. SAFP.13 = RPA_A1170.pdf Protea Asphalt’s Experience in Bitumen-Rubber Dachtler, J.D. 8 pages Bitumen-rubber is a blend of bitumen and rubber crumb, this normally being produced from pneumatic tyres. It should be stressed that the product being discussed in this paper bears little relationship to the product used 40 years ago; the products in current use contain larger quantities of rubber crumb and are produced under carefully controlled production conditions. The main countries where bitumen-rubber is used are Australia and Southern USA; it is interesting to note the similarity in climatic and road infrastructure between these two areas and South Africa. All three areas are essentially dry, have high road temperatures, and do not

have the full depth asphalt roads found in Europe or cooler wetter climates. The bitumen-rubber technology used by Protea Asphalt is based on the Sahuaro Pertroleum and Asphalt Company, Phoenix, Arizona technology, and has been developed by Protea to allow for the bitumen, rubber crumb, and climatic conditions, specific to South Africa. Bitumen-rubber in South Africa is currently produced by three companies, and since its introduction to the South African market two years ago; its use has rapidly expanded. Protea Asphalt is active in three main areas, these being surface dressing, crack sealing and bitumen-rubber premix. SAFP.14 = RPA_A1171.pdf The Use of Rubberized Bitumen Bergh, A.O. Macintosh, Bergh & Sturgess 10 pages In South Africa the use of latex in emulsion has also been effectively used in various ways for the last 10-15 years, but the introduction of scrap rubber into hot bitumen has only recently been done and it might serve some purpose to review the situation in order to obtain a balanced and practical assessment of the efficiency of this relatively new product in this country. SAFP.15 = RPA_A1172.pdf The Uses of Bitumen-Rubber Binders in Interim Rehabilitation Measures Aimed at Prolonging the Life of Distressed Pavement Structures Maree, J.H., Scott & de Waal Francis, V.C. & Van Der Walt, Dept. of Transport 8 pages One of the main functions of a surfacing layer of a pavement structure is to prevent the ingress of water. Research with the Heavy Vehicle Simulators demonstrated that even light pavement structures can carry large numbers of axles, provided that water is kept out. It is therefore not surprising that modified binders, with superior crack sealing properties, are currently very much in favor in the rehabilitation field. The purpose of this paper is to describe the uses of bitumen-rubber binders in interim rehabilitation measures aimed at prolonging the life of distressed pavement structures. SAFP.16 = RPA_A1173.pdf Field Testing and Control of Bitumen-Rubber Stauss, P.J., Director of Bruinette Kruger Stoffberg Inc. 10 pages This paper will first discuss the more important properties of bitumen-rubber and their possible relation with performance and then some practical aspects in field control and testing will be referred to. SAFP.17 = RPA_A1174.pdf Specifications for Bitumen-Rubber – Recent Development in the RSA Myburgh, P.A. Executive Director, S.A. Bitumen & Tar Association

13 pages This paper briefly sketches the developments in compiling a specification for bitumen-rubber during the period May 1983 to May 1984.

INTERNATIONAL REPORTS: SWAZILAND COST

SC.1 = RPA_A1175.pdf A Case Study: The Cost Effective Use of Bitumen-Rubber on Municipal Roads in Mbabane, Swaziland Dlamini, M.A.V., Town Engineer & Mbabane Town Council, & Renshaw, R.H., Technical Manager & Tosas (Pty) Ltd. 6 pages This paper outlines the basis of the decision to use bitumen-rubber single surface treatment as a “holding action” until sufficient funds become available to perform the recommended rehabilitation of severely deteriorated roads. The surface treatments performed better than expected with no deterioration after 4 ½ years of service. The paper provides a cost comparison, which shows the bitumen rubber surface treatment to be cost effective.

INTERNATIONAL REPORTS: SWEDEN NOISE

SWEN.1 = RPA_A1176.pdf Do Road Surfaces with Rubber Give Noise Reductions? Sandberg, Ulf Swedish Road & Transport Research Institute April 1, 1992 3 pages The paper contends that porosity of the surface is responsible for noise reduction and that rubber (dry process) does not directly contribute to noise reduction. Reference is made to a new pavement, “poroelastic surface,” under experiment in Sweden that has promise for noise reduction if certain engineering problems can be solved. SWEN.2 = RPA_A1177.pdf Low Noise Road Surfaces: A State-of-the-Art Review Sandberg, Ulf Swedish Road & Transport Research Institute March 31, 1992 58 pages This paper is an extension of the review in SWEN.1. SWEN.3 = RPA_A1178.pdf Tire/Road Noise on Rubberized Asphalt and Cement Concrete Surfaces in Sweden Sandberg, Ulf & Gustavsson, Eva, Swedish Road & Traffic Research Institute; Ejsmont, Jerzy A., Technical University of Gdansk, POLAND Swedish Association of Local Authorities 1990 56 pages Studies were conducted on “RUBIT,” which is essentially the same as the patented dry process used in the United States. Conclusions are that rubber does not directly contribute to noise reduction unless an unrealistically high proportion of rubber is used.

INTERNATIONAL REPORTS: SWEDEN PERFORMANCE

SWEP.1 = RPA_A1179.pdf Use of Tire Rubber in Asphalt Pavements in Sweden Rich, Frank M., P.E. Planning & Pavement Engineer, North Dakota Division November, 1993 31 pages Reports on the use of Rubit (PlusRide) in Sweden. Discusses the quantity used, wear resistance, noise reduction, cracking resistance and costs.

INTERNATIONAL REPORTS: UNITED KINGDOM MISCELLANEOUS

UKM.1 = RPA_A1180.pdf Some British Experience of the Behavior of Furnace Bottom Ash and Slate Waste for Pavement Foundations Dawson, A.R. & Nunes, M.C.M. FHWA/ EPA October, 1993 17 pages The paper describes studies accomplishes at the University of Nottingham with two secondary aggregates used in road construction: furnace bottom ash (FBA) and slate waste. Both materials are described in terms of the industrial processes, which generate them, availability, location and present use in the construction industry. In addition to conventional characterization and classification tests for aggregate materials, repeated load triaxial tests were performed. For the FBA, the material‟s degradation under compaction, its self-cementation and permanent deformation characteristics were also assessed. The FBA fails to meet the British DOT specification for primary aggregates for sub-base layers. However, the results indicate that it has adequate properties for use in lightly trafficked roads. Although the slate waste meets the Dot specification and laboratory testing indicates good resilient modulus characteristics, its present utilization is currently limited. The benefits, disadvantages and feasibility of both materials for road construction are discussed. UKM.2 = RPA_A1181.pdf 20th WEDC Conference: Colombo, Sri Lanka, 1994 Rubber Recycling Ahmed, Rehan & Van de Klundert, Arnold LoughBorough University 1994 5 pages This is a summary of WEDC Conference held in Sri Lanka.