Characteristics of waste tire rubber (WTR) and amorphous poly alpha olefin (APAO) compound modified porous asphalt mixtures

摘要

Waste tire rubber (WTR) and amorphous poly alpha olefin (APAO) compound modified asphalt had good high temperature and anti-aging properties, which were needed for porous asphalt (PA) mixtures. The purpose of this paper was to evaluate the feasibility of WTR/APAO (WTR+4%APAO and WTR+6%APAO) compound modified asphalt for PA mixture and compare it with 70 # base asphalt, WTR modified asphalt and Tafpack Super (TPS) modified asphalt for PA mixture. First, the Cantabro test and draindown test were carried out to determine optimum asphalt contents (OAC) for all asphalt mixtures. Then, a series of performances tests were conducted on the asphalt mixtures at their OAC, including Marshall test, rutting test, low temperature three-point bending test, immersion Marshall test, Cantabro test before and after aging, pendulum friction test, to assess the high and low temperature performance, water resistance, aging resistance and skid resistance, respectively. The test results showed that as compared to WTR PA mixture, WTR/APAO PA mixture had smaller Cantabro abrasion loss, draindown and OACs, better high temperature performance, water, aging and skid resistances, and worse low temperature performance. WTR+6%APAO PA mixture had the best high temperature performance and water resistance of all PA mixtures. The aging resistances of WTR+6%APAO PA mixture was second only to that of TPS PA mixture. The skid resistance of WTR+6%APAO PA mixture was second only to that of 70# PA mixture. It was feasible to using WTR/APAO modified asphalt as the binder of PA mixture in non cold area according to Chinese standard JTG F40-2004 and WTR+6%APAO PA mixture performed better than WTR+4%APAO PA mixture. Future research was recommended on the influence of compaction condition and asphalt content on the WTR/APAO PA mixture properties such as fatigue resistance and permeability. (C) 2020 Elsevier Ltd. All rights reserved.