Use of recycled glass powder to improve the performance properties of high volume fly ash-engineered cementitious composites

High-volume fly ash (HVFA) Engineered Cementitious Composites (ECC) show reduced strength and physical properties, especially at early curing ages. The goal of this study was to improve their strength characteristics by incorporating recycled glass powder (RGP) for enhanced material sustainability. Composites containing 15, 30, 45 and 60% RGP as a replacement for FA, with FA to cement ratio of 2.2, were studied in HVFA-ECC. Standard ECC mixtures with FA to Portland cement (FA/PC) ratio of 1.2, and HVFA-ECC with FA/C ratio of 2.2 without RGP were also produced as control mixtures. The experimental results confirmed that incorporating RGP into HVFA-ECC significantly improves compressive and flexural strengths, chloride ion resistance and electrical resistivity, and results in a comparable ductility to standard ECC, based on FA to cement ratio of 1.2. Furthermore, self-healing of HVFA-ECC was accelerated and final recovery rate of strength and physical properties improved. Microstructural analysis showed high portlandite consumption and the formation of low Ca/Si ratio in new C-S-H structures near C-Na-Al-S-H as the main outcome of the binary admixture in ECC.