Low-Cement Concrete with Coarse Recycled Concrete Aggregate: Technical Assessment and Cost Analyzes
DOI:
https://doi.org/10.46421/enarc.v9i1.6762Keywords:
Low-Cement concrete, Recycled aggregate concrete, CO2 Reduction, Binder Intensity IndexAbstract
This study evaluates the compressive strength, cement use efficiency (through the binder intensity index; kgcement/strength), and costs of concretes with recycled concrete coarse aggregates (ARCO), using limestone filler and dispersing admixtures. This strategy aims to reduce cement consumption and produce low-carbon concrete. Three mix compositions were analyzed: reference (N-REF), low-cement consumption with natural aggregate (N-RED), and low-cement consumption with ARCO (R-RED). The results indicate that the use of fillers and admixtures allowed for a 30% reduction in binder intensity (9.8 → 6.8 kg cementm⁻³MPa⁻¹) in the N-RED mix and 20% (9.6 → 7.8) in the R-RED mix compared to N-REF. The characteristic compressive strength of the N-RED mix decreased by ~22% (32.8 MPa → 25.5 MPa), while that of the R-RED mix decreased by ~5.5% (25.5 MPa → 24.1 MPa) relative to N-RED. The R-RED mix showed a 10% cost reduction (R$311/m³ → R$280/m³) compared to the other concretes. These results demonstrate the feasibility of producing structural-strength concretes (>C20) with lower cement consumption, using 100% ARCO, and at a cost similar to conventional concrete, exceeding current regulatory limits and contributing to the sector's decarbonization.
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