Optimization of compressive strength in admixture-reinforced cement-based grouts

The Taguchi method was used in this study to optimize the unconfined (7-, 14- and 28-day) compressive strength of cement-based grouts with bentonite, fly ash and silica fume admixtures. The experiments were designed using an L-16 orthogonal array in which the three factors considered were bentonite (0%, 0.5%, 1.0% and 3%), fly ash (10%, 20%, 30% and 40%) and silica fume (0%, 5%, 10% and 20%) content. The experimental results, which were analyzed by ANOVA and the Taguchi method, showed that fly ash and silica fume content play a significant role in unconfined compressive strength. The optimum conditions were found to be: 0% bentonite, 10% fly ash, 20% silica fume and 28 days of curing time. The maximum unconfined compressive strength reached under the above optimum conditions was 17.1 MPa.