What question did this study set out to answer?

This investigation aims to assess the mechanical, environmental, and economic performance of concrete with recycled coarse aggregates and granulated slag.

March 29, 2026Open Access

Multi-scale performance, life-cycle and economic assessment of blended concrete using recycled coarse aggregates

Key Points

This investigation aims to assess the mechanical, environmental, and economic performance of concrete with recycled coarse aggregates and granulated slag.
Evaluated varying replacement levels of recycled coarse aggregate (0% to 65%) in concrete mixes.
Conducted mechanical testing to determine compressive strength at 28 days.
Performed microstructural analysis using SEM-EDS.
Implemented life cycle assessment according to ISO 14040:2006.
Conducted economic analysis including lifecycle cost and sensitivity analysis.
Optimal compressive strength achieved at 12.5% RCA replacement with 55.43 MPa, a 13% improvement.
Higher replacement ratios led to significant strength deterioration, with 65% RCA resulting in a 48% reduction.
Life cycle assessment showed a 27% reduction in carbon emissions for the optimal mix.
Economic analysis indicated 30.6% cost savings over 50 years despite a modest initial cost reduction.

Abstract

The construction industry confronts dual challenges of natural resource depletion and construction waste accumulation, necessitating sustainable alternatives to conventional concrete production. This investigation evaluated mechanical properties, microstructural characteristics, environmental impacts, and economic feasibility of concrete incorporating recycled coarse aggregate (RCA) at varying replacement levels (0%, 12.5%, 25%, 50%, 65%) with ground granulated blast furnace slag (GGBS) supplementation (20%, 25%). Mechanical testing revealed optimal performance at 12.5% RA replacement, achieving 55.43 MPa, compressive strength at 28 days, representing 13% improvement over control specimens. Higher replacement ratios demonstrated progressive strength deterioration, with 65% replacement yielding 48% reduction in compressive strength. Microstructural analysis through SEM-EDS confirmed enhanced interfacial transition zone densification in RA12.5%+GGBS mixes, correlating with superior mechanical performance. Life cycle assessment following ISO 14040:2006 demonstrated 27% reduction in carbon emissions (282.2 vs. 386.7 kg CO₂-eq/m³) for RA12.5%+GGBS25% configuration, with manufacturing processes contributing 46.5% of total environmental burden. Environmental impact categories showed consistent improvements, particularly resource depletion (28.2% reduction) and terrestrial acidification (24.2% reduction). Economic analysis revealed 30.6% lifecycle cost savings (₹13,550/m³) over 50-year service period despite modest 5.3% initial cost reduction, with 2.1-year payback period and favorable sensitivity to carbon pricing mechanisms (-3.8% per ₹100/ton CO₂). Sensitivity analysis identified cement price volatility as primary economic risk factor (± 6.8% impact). The convergence of optimal mechanical, environmental, and economic performance at 12.5% RCA with 20–25% GGBS substitution challenges conventional assumptions regarding linear sustainability benefits, establishing critical thresholds for sustainable concrete design in infrastructure applications.

Bookmark

View Full Paper

Cite This Study

Chaitanya et al. (Thu,) studied this question.

synapsesocial.com/papers/69c8c1d7de0f0f753b39bffb https://doi.org/https://doi.org/10.1038/s41598-026-45095-y

Bookmark

View Full Paper