The effect and modeling of bituminous schist on the performance of bituminous hot mixes

In recent years, developments in industry and technology, population growth, and rising living standards have increased production in many sectors and, consequently, raw material consumption. The desire to use local resources economically has led to their depletion. Therefore, various solutions are being developed to meet raw material needs. The evaluation of waste materials is one such solution, and its importance is growing. Evaluating waste materials in different fields and for multiple purposes will contribute to sustainable environmental development and the reduce of production costs. This thesis examines the effect of using waste bituminous schist (WBS) from coal mines as a substitute for aggregate in bituminous hot mix (BHM) on highway performance. WBS was layered, ground, and screened, then used to replace 10, 20, 30, and 40% by weight of fine and filler aggregates passing the 1.18 mm sieve. After characterizing aggregate, bitumen, and WBS, Marshall stability, static and dynamic creep, and indirect tensile strength tests were performed on BHM samples designed via Marshall and Superpave methods. Variance and regression analyses were applied to evaluate the significance of the results When the results were examined, it was determined that 10% WBS ratio was the most effective percentage considering many performance characteristics of the BHM samples. It is seen that the optimum bitumen ratio increased in the Superpave design method compared to the addition of WBS to the BHM and the Marshall design method.