الهه نصیری امیری

One of the efficient methods in preventive maintenance of pavements is implementing the slurry seal. This study is done with the objective of investigating the feasibility and effect of using waste coal powder as natural filler replacement in the slurry seal mix design. At the first stage, the properties of aggregate and waste coal powder were investigated. Then, in order to evaluate the performance of mixtures, use was made of 5 different combinations, containing 0, 25, 50, 75 and 100% coal powder as the filler replacements based on filler weight in slurry seal mixture. Evaluation of the specimens were performed using the wet cohesion test, wet track abrasion test, loaded wheel- sand adhesion test and loaded wheel-displacement test according to ASTM D3910. The results showed that the specimens containing waste coal powder cause improvement in the slurry seal performance. In the wet track abrasion test, the lowest amount of weight loss in samples, related to mixtures containing 50 and 75 percent coal powder is 176 and 202 g/m2, respectively. In the loaded wheel-displacement test, it was found that the vertical and lateral displacement was reduced by increasing the percentage of coal powder up to 75%. Also among the mixtures, the one with 50% waste coal powder had the best performance so that in comparison to the control specimen has exhibited increased cohesion by 12.1% and 14.29% at 30 and 60 minutes times, respectively. Furthermore, the moisture susceptibility and vertical displacement of the mixture was reduced by 27.6% and 32%, respectively.