Possibility of utilizing recycled concrete aggregates in HMA mixture

الملخص EN

Environmental and economic considerations have encouraged civil engineers to find ways to reuse recycled materials in new constructions.

The objective of this research was studying the possibility of utilizing recycled concrete RC in a surface course of hot mix asphalt HMA mixtures and evaluating the volumetric and mechanical properties of hot mix asphalt mixtures containing recycled concrete aggregates.

For this purpose, the performance of HMA mixtures containing various percentages of RC has been evaluated based on experimental tests, such as Marshall Stability MS, Marshall flow, Marshall stiffness, and Indirect tensile strength ITS.

90 specimens contain 5% asphalt bitumen and RC in various percentages (10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100%) were mixed with virgin crushed stone aggregates and compacted by using Marshall Compactor to produce HMA specimen then Marshall mix design method was used to measure the optimum RC content.

The results of MS and flows slightly decreased with the addition of RC.

Marshall stiffness values for 10 percent RC was higher than the Control Specimen CS and the others.

ITS values decreased with increasing RC.

A mixture without recycled concrete RC and varies gradation of maximum size of (1 ) inches was prepared as control mix to CM test the Marshall stability –flow , ITS, and temperature sensitivities properties of mixes with 58% ( optimum percent) of RC that is obtained from a mix design that was investigated in this study.

Specimens showed slightly improvements in Marshall Stability, flow, and ITS as compared with CM.