Using a Numerical Method for Designing an Asphalt Mix with Specific Aggregate Material Properties

Abstract

Abstract Common approaches for designing asphalt mixes mainly deal with the determination of the optimal percentage of the binder content, which is performed according to the volumetric properties, durability index, and strength of the produced asphalt. In this regard, laboratory results of asphalt mix designs, considering the changes in physical properties of the aggregates from production to the distribution of hot mix asphalt, highlight the need for fabrication of cyclic control specimens. The approach presented in this study allows the reduction of human mistakes during samples preparation, easy control of optimum binder content with respect to the probable changes in the aggregate sizes in each step of fabrication, transportation and implementation of the hot asphalt mix, and provide a uniform ultimate surface of the distributed asphalt. By adjusting the numerical values of the factors effective on the optimum binder percentage and constructing some statistical regression models in statistical package for the social sciences (SPSS), we obtained a set of linear equations that give the optimum binder percentage as a function of aggregate size, binder absorption, specific gravity of the mix, and specific surface of the materials. According to the results of the SPSS 23 analysis, the optimum binder content of the aggregates from 30 different mines was evaluated with respect to their grain size. Based on the obtained results and Marshall Laboratory test data, we extracted some relations for estimating the optimum binder content for hot mix asphalt. Using this method, the optimal binder content is determined using the results of the sieve analysis of the aggregates without the need for repetitive fabrication of asphalt specimens or spending a long time. Consequently, the optimal binder content for the 0–19-mm binder and 0–13-mm topcoat asphalts was determined with high accuracy.