Properties of recycled aggregates from different composition and its influence on concrete strength

Propriedades dos agregados reciclados de diferentes composições e sua influência na resistência do concreto

abstract:

As a solution to the high depletion of natural resources and huge waste generated by the construction industry, the use of coarse recycled aggregate has become a trend in many countries. The construction and demolition waste is heterogeneous and mostly composed of concrete and masonry debris. The recycling process usually involves not only crushing and screening but also advanced techniques to separate these two fractions. These processes are costly and most frequently ineffective. Although most studies and international standards focused only on recycled concrete aggregate for structural use, it is possible to achieve similar characteristics with mixed recycled aggregates that have a ceramic fraction of up to 20%. This initiative can decrease recycling costs and make it more feasible. Therefore, this work presents an experimental investigation of a Brazilian recycled aggregate, which was separated into three fractions: mixed, concrete, and masonry aggregates. The analyses showed that the mixed recycled aggregate displayed geometric, physical, and mechanical properties similar to the recycled concrete aggregate. In addition, concrete made with 20% of mixed recycled aggregate presented a reduction of only 0.6% in maximum compressive strength and 36.8% in the modulus of elasticity compared with concrete made with the same amount of recycled concrete aggregate.

Keywords:
sustainability; construction and demolition waste; recycled aggregate