Substitution of the natural aggregate filler by coal waste powder (CWP) in microsurfacing surface treatment: Mix design and performance evaluation

Abstract

• This study focused on use of CWP in microsurfacing mixture. • Effects of physical and chemical properties of CWP on mixture performance analyzed. • Evaluating performance in terms of cohesion, moisture damage, bleeding and rutting resistance. • CWP when added to an optimum content could produce superior mixture. • The mixture containing 5% CWP is recommended to improve microsurfacing performance. Demand for waste materials has increased significantly due to the environmental impacts and limited natural resources. The current study mainly aimed to examine the application of coal waste powder (CWP) in microsurfacing mixture compared to natural aggregate fillers (NAF). Accordingly, wet cohesion, wet track abrasion, loaded wheel-displacement, and loaded wheel-sand adhesion tests were conducted in five different blends, containing 10 % NAF, 7.5 % NAF + 2.5 % CWP, 5 % NAF + 5 % CWP, 2.5 NAF + 7.5 % CWP, and 10 % CWP based on the total aggregate weight. Then, the CWP effects on the performance of microsurfacing mixtures were investigated using analysis of variance (ANOVA). Experimental results showed that mixtures containing CWP improved microsurfacing performance. Among the mixtures, the mixture containing 5 % CWP increased the bitumen adhesion in 30 and 60 min by 11.7 % and 13.6 % and reduced the vertical and lateral displacement by 34 and 26 %, respectively, while improving the abrasion strength by 25.2 % and reducing the bleeding potential about 48.6 %. Based on the results of ANOVA according to. P-Value parameters, CWP had a significant effect on cohesion, moisture sensitivity, reducing bleeding potential and reducing deformations due to traffic loading in the microsurfacing mixtures.