Effect of Reinforcement on Fatigue Life of Asphalt Beams

Abstract

A study was conducted to determine the effect of reinforcement on the fatigue lives of asphalt beams of size 76 × 76 × 610 mm, which were prepared in the laboratory with a typical surface layer asphalt mix. Three sets of nine beams each contained no reinforcement (control beams) and reinforcements consisting of nonwoven paving fabric and composite (woven grid and nonwoven fabric composite). Each set of beams was subjected to three different load levels (three beams were tested at each load level), and their fatigue lives were determined. The fatigue testing of these beams was carried out by placing the beam on an elastic foundation (approximately 150 mm deep, 76 mm wide, and 660 mm long) and loading the beam at the center. A fatigue load at a frequency of 2 cycles/sec was applied to each beam. Each load cycle consisted of a half sine wave of 0.1-sec duration and a rest period of 0.4 sec. The total number of fatigue loads to crack the entire depth of beam was recorded as its fatigue life. The data obtained from three different sets of the beams were analyzed to determine the effect of reinforcement on the fatigue lives of the beams. These analyses indicated that the beams reinforced with composite performed significantly better than the beams containing paving fabric alone, and the beams reinforced with fabric alone performed better than the unreinforced control beams. Further details of the study and the results are described.