Influence Of Recycled Aggregate Quality From Precast Rejection On Mechanical Of Self-Compacting Concrete

The use of coarse aggregates from crushing pre-existing concrete in the manufacturing of new concrete needs experimental results to validate its influence in the properties of the new concrete elements.In the present study we assessed the impact of using different proportions of replacement up to 100% of natural aggregates with recycled aggregates in the concrete properties; moreover, the effect of pre-treatments of pre-saturation, washing and the aggregates' source (from precast concrete rejected pieces and construction and demolition waste) was analysed. The best results were obtained with dry and washed recycled aggregates, the compressive strength increment was between the 8 and 17% compared to conventional concrete. Results also pointed out that recycled aggregate that exclusively comes from precast concrete pieces lead to a better concrete mechanical characteristic than the aggregates which origin is construction and demolition waste. In addition, a clear relationship between the percentage of recycled aggregate substitution and the workability and mechanical performance of self-compacting concrete is observed. The results presented in this paper allow to state that precast concrete factories can recycle their rejected elements into recycled coarse aggregates for manufacturing new products, this will allow to protect the environment by reducing the need of raw material consumption and the landfill.