Accelerated Pavement Testing to Compare Efficiency of Overlay Materials Used in Brazil

Abstract

In Brazil, asphalt rubber (AR) has been used to delay reflection cracking in overlays since the 1990s. To quantify reflection cracking evolution in AR and asphalt concrete (AC) overlays, an accelerated pavement testing (APT) study was carried out by the Federal University of Rio Grande do Sul and the State Roads Department. Overlays 5.0-cm thick were set on sections with identical structures (severely cracked AC wearing course and granular base), and from March 2003 to February 2005 a traffic simulator applied 100-kN axle loads on the two full-scale pavements. During the tests, cracks were recorded, and deflections and strains were measured. APT raw data suggested that the efficiency of the AR overlay in delaying reflection cracking was 5.55 times greater than that of the AC overlay. Because the overlays were tested in different seasons, a supplementary laboratory study was carried out to quantify temperature effect on AC and AR resilient modulus, later used in a fatigue analysis. With APT and fatigue analysis data combined, it was possible to ascertain that if both overlays were tested at identical pavement temperatures, the efficiency of the AR overlay delaying reflection cracking would be 4.84 times greater than that of the AC overlay.

Calibration of Inverted Asphalt Pavement Rut Prediction Model, Based on Full-Scale Accelerated Pavement Testing

“…The accelerated pavement testing (APT) technique emerges as the research requires, which aims to apply continuous wheel loads on full-scale test sections under controlled load and environmental conditions, until the structure fails within a short period of time [ 15 , 16 ]. Researchers from Australia [ 17 ], South Africa [ 18 ], the United States [ 19 ], France [ 20 ], Brazil [ 21 ], Costa Rica [ 22 ], and so on, have contributed a lot to the field over the last decades. Research results can be found in the long-term performance evaluations [ 23 , 24 , 25 , 26 ] and distress mechanism investigations [ 27 , 28 ] of pavement materials and structures, based on the APT technique, whereas there are lacking studies on the calibration methods of rut prediction models under complex test conditions, based on APT.…”