INVESTIGATION OF ASPHALT PAVEMENT WITH ADDED CRUMB RUBBER
Waste tires must be recycled in environmentally safe ways that meet civil engineering concerns while fulfilling standards for construction materials. Used tires can be processed into rubber powders with particle sizes of 0–2 mm, a suitable fine aggregate for mixing into road pavements. We tested asphalt mixtures with rubber added using the dry method, comparing their properties with a traditional mixture. We tested asphalt–rubber mixtures with rubber incorporated at either ambient temperature or preheated. Rubberized and traditional asphalt concretes compared well in void content, indirect tensile strength ratio, rut depth, and wheel-track slope. After optimizing the rubber content added, we laid an experimental road course with the asphalt–rubber mixture.
橡胶颗粒沥青混合料性能研究 Study on Capability of Crumb Rubber Asphalt Mixture
为了研究橡胶颗粒沥青混合料的路用性能，通过水稳定性、高温稳定性、低温抗裂性以及抗剥落性方面，对不同粒径、不同掺量的橡胶颗粒沥青混合料进行了对比。试验结果表明：橡胶颗粒的加入对沥青混合料的路用性有明显的改善作用，当掺量在3%时，对沥青混合料的改善效果达到最优。 In order to evaluate durability of rubber particles asphalt mixture, through water stability, high temperature stability, low temperature crack resistance and anti stripping property, the different amount of crumb and different particle sizes of rubber asphalt mixture were compared. Experimen-tal results show that the addition of rubber particles can improve the durability of asphalt mixture remarkably. When the dosage is 3%, the improvement effect of asphalt mixture is optimal.
ASPHALT DURABILITY CORRELATION IN IOWA
EIGHT ASPHALT CEMENTS AND PAVING PROJECTS USING THESE ASPHALTS WERE EVALUATED RELATIVE TO THEIR CHANGES IN RHEOLOGICAL AND CHEMICAL PROPERTIES IN PAVEMENT SERVICE FOR AS LONG AS 48 MONTHS. CORRESPONDING CHANGES IN THESE ASPHALTS OF THE SAME PHYSICAL AND CHEMICAL PROPERTIES WERE DETERMINED DURING LABORATORY AGING. THE IOWA DURABILITY TEST IS A TWO-STAGE AGING PROCESS COMBINING STANDARD TFOT AND PRESSURE-OXIDATION TREATMENT (20 ATM IN OXYGEN AT 150 F) UP TO 1,000 HOURS. GOOD CORRELATIONS BETWEEN FIELD-SERVICE AGING IN IOWA AND LABORATORY AGING DURING THE IOWA DURABILITY TEST HAVE BEEN OBTAINED. THE MASTER TIME-EQUIVALENCY CURVE BETWEEN THE TEST IN HOURS AND THE PAVEMENT SERVICE LIFE IN MONTHS, ESTABLISHED BY COMBINING ALL ASPHALTS (VOID LEVELS) AND ALL PROPERTIES, INDICATES THAT 46 HOURS IN TEST WILL AGE ASPHALTS TO THE EQUIVALENT OF 60 MONTHS IN SERVICE. CORRELATION CURVES FOR DIFFERENT PROPERTIES AND DIFFERENT LEVELS OF PAVEMENT VOIDS WERE ALSO OBTAINED. A TENTATIVE SPECIFICATION FOR PAVING ASPHALTS, INCLUDING DURABILITY REQUIREMENTS BASED ON THE TEST, IS SUGGESTED IN LIEU OF CURRENT TFOT.