Synergistic strength enhancement of CDW-based brick using polycarboxylate ether with cement

Abstract The construction industry urgently needs sustainable solutions for recycling Construction and Demolition Waste (CDW). This study investigates the synergistic effects of Ordinary Portland Cement (OPC) and Polycarboxylate Ether (PCE) superplasticizer on the compressive strength of CDW-based bricks. Results of using the PCE polymer alone indicated that the polymer alone does not affect the strength significantly, whereas the strength reached 0.32 MPa using 5 % PCE. Evaluation of mixtures with 0–50 % OPC and 0–10 % PCE, reveals that 3 % PCE combined with 30 % OPC yielded the highest compressive strength (11.2 MPa) – nearly double that of OPC alone (5.95 MPa). Mechanistic studies, including zeta potential analysis and UV-VIS dispersion testing, demonstrated that PCE enhances particle dispersion via electrostatic repulsion (−25 mV charge) and steric hindrance, optimizing hydration. These bricks meet strength requirements for lean-mix concrete (LMC) and structural fills, offering a viable path for sustainable construction.