Enhancement of mechanical and microstructural properties of high-volume slag cement paste using treated cedar wood fly ash

High-volume slag cement (HVSC) is a sustainable alternative to traditional cement but exhibits low early-age strength. This study explores the use of treated cedar wood fly ash (CWFA) as an additive in HVSC paste, focusing on fresh, mechanical, and microstructural properties. Paste mixtures were prepared using varying proportions of ground granulated blast-furnace slag (GGBFS) and cement at ratios of 30:70, 50:50, and 70:30, with CWFA added at replacement levels of 10%, 20%, and 30% by weight of the binder. The results indicated that incorporating 10% and 20% CWFA increased heat evolution within the first 48 h by 25.5% to 60.5% compared to mixtures without CWFA. This accelerated hydration significantly improved early-age compressive strength, with enhancements ranging from 50% to 165%, particularly in mixtures containing 50% and 70% GGBFS. This research provides a solution to the early-age strength limitations of HVSC systems and contributes to the development of green cementitious materials.HighlightsHigh-volume slag cement (HVSC) and cedar wood fly ash (CWFA) were used to produce the modified paste.The incorporation of CWFA enhances the hydration reaction, resulting in an increased heat of hydration.Adding CWFA significantly enhances the early-age strength of the HVSC paste.Using CWFA improves the microstructure of the HVSC paste.Using a high volume of GGBFS along with CWFA reduces CO2 emissions. High-volume slag cement (HVSC) and cedar wood fly ash (CWFA) were used to produce the modified paste. The incorporation of CWFA enhances the hydration reaction, resulting in an increased heat of hydration. Adding CWFA significantly enhances the early-age strength of the HVSC paste. Using CWFA improves the microstructure of the HVSC paste. Using a high volume of GGBFS along with CWFA reduces CO2 emissions.