Evaluation of fatigue and rutting performance of sewage sludge ash (SSA) in asphalt concrete

A study was conducted evaluating the effects of sewage sludge ash (SSA) in hot mix asphalt (HMA) as mineral filler and/or as a fine aggregate substitute. For the purposes of this study, 0% and 2% SSA by weight of aggregates were used in HMA samples. Fatigue and rutting performance of HMA was evaluated using disk-shaped compact tension testing (DCT) and creep compliance testing respectively. DCT and creep compliance were used to determine the fracture energy and slope of secondary region to evaluate fatigue and rutting performance. Through these tests, it was found that the fracture energy and slope of the secondary region for HMA containing 0% and 2% SSA were statistically similar. From these tests, it was concluded that the HMA with 2% SSA shows similar performance in fatigue and rutting as that of 0% SSA. Since the performance of the HMA does not drop with the addition of 2% SSA, future studies could be conducted analyzing the effects of higher percentages of SSA, which could significantly reduce the amount of raw materials required in construction.