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Waste Product Profiles
Published in John T. Aquino, Waste Age/Recycling Times’, 2020
Rubberized asphalt is not without drawbacks, however. The initial investment cost is high, often twice normal highway repair cost, although rubberized asphalt can double pavement lifetime. In addition, rubberized asphalt does not have long-term performance test results, may not itself be recyclable, lacks national specifications, and is a change in the recipe for a product with long-established specifications.
Solid Waste Source Reduction and Recycling
Published in Charles R. Rhyner, Leander J. Schwartz, Robert B. Wenger, Mary G. Kohrell, Waste Management and Resource Recovery, 2017
Charles R. Rhyner, Leander J. Schwartz, Robert B. Wenger, Mary G. Kohrell
The use with the greatest potential for consuming large quantities of waste tires is rubberized asphalt. It has been estimated that rubberized asphalt lasts up to 4 times longer than standard asphalt, at about twice the cost (Areata Community Recycling Center, 1990). Many states, including New York, Florida, and Oregon, are now using rubberized asphalt due to such cost and performance criteria. The use of rubberized asphalt grew by about 30% per year during the early 1990s. Some additional utilization of crumb rubber in roads could result from the 1991 Intermodel Surface Transportation Efficiency Act (ISTEA). Section 1038 of ISTEA requires states to meet certain minimum recycled rubber utilization requirements for asphalt in federally-funded road projects. However, Section 1038 has been widely contested by many groups since its passage, and thus it may not increase crumb rubber utilization.
The Uses of Cryogenically Recycled Rubber
Published in Norman R. Braton, Cryogenic Recycling and Processing, 1980
Rubberized asphalt pavements and seal coats offer an important use for recycled rubber particles. As has been described by McDonald and Olsen,5 the recycled rubber of 16 to 25 mesh size is added to penetration grade asphalts in amounts up to 40 weight percent rubber. Usual amounts are about 25%. The mixture is blended at 149° to 232°C (300° to 450°F) to a thickened mixture. (At room temperature the material is an excellent tough binder). The hot mixture is applied to the original cracked pavement at a rate of 1.8 to 3.8 × 103 m3/m2 (0.4 to 1 gal/yd2). After the application of the rubber-asphalt binder, a cover stone 0.95 cm (3/8 in.) nominal size is applied at about 21 kg/m2 (38 lb/yd2) and subsequently embedded into the binder by rolling. This rubber-asphalt binder seal prevents cracking, acts as a moisture barrier, inhibits bleeding of the asphalt in hot weather, and gives less brittleness at cold temperatures.
Bio-modification of rubberised asphalt binder to enhance its performance
Published in International Journal of Pavement Engineering, 2019
Elham H. Fini, Shahrzad Hosseinnezhad, Daniel Oldham, Zachery Mclaughlin, Zia Alavi, John Harvey
Typically, rubberised asphalt shows better fatigue resistance and cracking resistance than conventional asphalt, and increasing the rubber percentage enhances the fatigue resistance (Lee et al.2008). The improved cracking resistance at low and normal temperatures, increased service life, improved rutting resistance, decreased traffic noise and increased skid resistance are the reasons for using rubberised asphalt. However, the application of rubberised asphalt has not been widely accepted for several reasons: lower workability due to the higher viscosity, high energy consumption because of increased processing temperature, low pumpability and unstable storage properties (Lo Presti 2013). The vulcanised crosslinking structure of rubber particles absorbs lighter compounds from the binder, increasing the size of the rubber particles during the mixing with asphalt binder. This phenomenon decreases the free space between the swollen rubber particles, which consequently increases the viscosity of the asphalt binder (Ghavibazoo et al.2013). The increase in viscosity due to the physical filler effect and swelling effect requires a higher temperature during mixing time, which leads to degradation of the rubber particles and higher fuel consumption. The difference in the density of rubber and asphalt binder results in separation and consequent clogging in tubes and nozzles (Lo Presti 2013).
Performance evaluation of rubberised asphalt mixes containing WMA additives
Published in International Journal of Pavement Engineering, 2018
Hassan Ziari, Mohsen Naghavi, Reza Imaninasab
In the recent decades, different types of distresses formation and deterioration rate of pavements have been accelerated due to the dramatic growth of traffic volume. Mix design modification, materials optimisation and effective production process can be employed to decelerate such negative acceleration (Isacsson and Lu 1995). Moreover, improving bitumen properties with the aid of different types of additives is becoming a practical approach to enhance performance of asphalt mixtures. Using waste polymer like rubber is particularly beneficial since Rubberised asphalt mixtures are environmentally friendly due to recycling used tire and service life increase (Takallou and Sainton 1992, Oliveira et al.2013).
Editorial
Published in Road Materials and Pavement Design, 2020
Rubberized asphalt, a product of combining crumb rubber from recycled tires and hot paving grade asphalt, is not a new material for producing enhanced asphalt binder and paving mixes. The very first experiments with rubberized asphalt started before the Second World War in Netherlands/Germany, were evaluated after the war in England, but only became more extensively used in Arizona, USA, after Charles McDonald got a patent for the development of what is called today the ‘wet method’. The ‘wet method’ rubberized asphalt has been successfully used as an asphalt binder in seal coats and hot asphalt mixes all over the world for the last 50 years.