Abstract
This paper intends to evaluate the feasibility of reintroducing recycled concrete aggregates in the precast industry. The mechanical properties of self-compacting concrete (SCC) with incorporation of recycled aggregates (RA) (coarse recycled aggregates (CRA) and fine recycled aggregates (FRA)) from crushed precast elements were evaluated. The goal was to evaluate the ability of producing SCC with a minimum pre-established performance in terms of mechanical strength, incorporating variable ratios of RA (FRA/CRA%: 0/0%, 25/25%, 50/50%, 0/100% and 100/0%) produced from precast source concretes with similar target performances. This replication in SCC was made for two strength classes (45 MPa and 65 MPa), with the intention of obtaining as final result concrete with recycled aggregates whose characteristics are compatible with those of a SCC with natural aggregates in terms of workability and mechanical strength. The results enabled conclusions to be established regarding the SCC’s produced with fine and coarse recycled aggregates from the precast industry, based on its mechanical properties. The properties studied are strongly affected by the type and content of recycled aggregates. The potential demonstrated, mainly in the hardened state, by the joint use of fine and coarse recycled aggregate is emphasized.
Highlights
The consumption of natural resources in the construction industry has been growing in the last decades, as well as the production of demolition, construction and rehabilitation works waste
The results enabled conclusions to be established regarding the self-compacting concrete (SCC)’s produced with fine and coarse recycled aggregates from the precast industry, based on its mechanical properties
In general, the variations registered in SCC with recycled aggregates (RA) are due to the higher water rougher surface when compared to the natural aggregates (NA)
Summary
The consumption of natural resources in the construction industry has been growing in the last decades, as well as the production of demolition, construction and rehabilitation works waste This process of “construction-demolition” has exerted great pressure on natural resources, especially the natural aggregates (NA), and generated high levels of the so-called construction and demolition waste (CDW), often ending up in landfills. Both these aspects have a negative impact on the environment. The use of recycled aggregates (RA) to produce new concrete seems to be a potential solution It could solve the problems related with storage, transportation and dumping of CDW and contribute to the sustainability of the environment by adding value to this waste and limiting the consumption of NA
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