Effect of Crushing Method on the Properties of Produced Recycled Concrete Aggregates

Construction and Demolition Waste (C & DW) is generated around the world and its quantity will increase in the future. Recycling has become the favored method of dealing with concrete waste but, to avoid its downcycling, it is important to develop a recycling process which is able to produce high-grade recycled concrete aggregates (RCA). To that end, studying the influence of the production process on the properties of RCA can prove to be a crucial step toward a more circular construction industry. In this study, the influence of the crushing method is investigated. Samples of five laboratory-made concretes have been crushed using the most common mechanical crushing methods (impact crusher and jaw crusher), and the particle size distribution, morphology, hardened cement paste content and water absorption of the produced RCA have been measured and analyzed. The findings indicate that the use of impact crushers results in the production of RCA possessing more spherical geometric characteristics, albeit with a broader particle size distribution and a relatively higher content of fine particles as compared to those obtained from jaw crushers. Additionally, it is observed that the employed crushing technique seemingly exerts no discernible impact on the hardened cement paste content and the water absorption in the context of the studied concretes.