Study on improving the early-age strength of fly ash concrete using chemical admixtures

Abstract

This study investigates the effectiveness of a chemical accelerating admixture (TC3) in improving the early-age performance of fly ash (FA) concrete. Class F fly ash was used as a partial cement replacement at levels of 0%–40% by binder mass, while TC3 was incorporated at a dosage of 2% to compensate for the loss of early-age strength associated with FA incorporation. Concrete performance was assessed in terms of workability, setting time, and compressive strength at 1, 3, 7, and 28 days. The results showed that FA improved workability but prolonged setting and reduced early-age strength, especially at high replacement levels. By contrast, TC3 significantly shortened the setting time and enhanced early-age compressive strength, particularly at 3 days, thus offsetting the adverse effect of FA on early strength development. These findings demonstrate that TC3 provides a viable approach for increasing FA utilization in concrete without compromising its early-age performance.