Evaluation of the Properties of Recycled Concrete Aggregate and Their Potential Use in Road Paving

Abstract Concrete is one of the most widely used building materials due to its many advantages, which results in large amounts of concrete waste resulting from demolition. This study will be an attempt to produce an environmentally friendly road. In this research, recycled aggregates were used according to the class A and B, used in the Iraqi specifications for roads and bridges (SORB). Two methods were used, the first method was to use recycled aggregate of class A and B with different proportions of fine soil, as a binding material for the aggregate particles, and the second method was to use recycled aggregate of class A and B with different proportions of fly ash as a binding material for the aggregate particles. The physical and mechanical properties of the recycled aggregate were studied, the behaviour of road layers designed from recycled aggregate was also studied by determining the California bearing ratio in dry and wet conditions, as well as the unconfined compressive strength. The research showed that when using( 5%,10%,14%)of fine soil with recycled aggregate, the California bearing ratio fit gave high and acceptable values. However, when increasing the ratio to 16%, the values decreased from 41.0% to 38.7% for class A in the soaking state, but in the unsoakhng state, it decreased from44.6% to 42.0% and Also the class B values decreased in the soaking state from 41.4% to 39.3%, and in the un soaking state from 45.0% to 43.2%,Likewise The unconfined compressive strength decreased by 25% when the fine soil content increased to 16% while the values increased with increasing fly ash content. This study concluded that it is possible to use recycled aggregate in the design of road layers, especially since the values of the California bearing ratio of recycled aggregate are greater than the values of natural aggregate used in road works. Thus, this study achieved a major goal from an environmental and economic perspective.