Effects of cement content and curing period on strength enhancement of cemented calcareous sand

Abstract

Cement treatment is a promising and effective method to enhance strength of calcareous sand in regions where offshore foundations and coastal facilities are localized. In treatment, the added cement content and curing period influence the strength of cemented calcareous sand. In order to regulate the loading resistance of cemented calcareous sand, effects of cement content and curing period on strength enhancement are investigated experimentally. First, cemented specimens with 5%, 7.5%, and 10% cement contents and 1–28 days curing period are prepared. Then, unconfined compression test is conducted to measure strength. Nuclear magnetic resonance test is also performed to analyze microstructure change during hydration reaction. An empirical equation of strength is derived, considering the effects of cement content and curing period. This equation shows higher accuracy than existing empirical models. In addition, the microstructure change in hydration process is quantified by pore volume evolution. Void ratio is used to characterize the pore volume evolution. Hence, the dependence of strength on cement content and curing period is quantitatively explained by the change in void ratio. This sheds light on hydration reaction in cement treatment by cement content and curing period and the regulation of strength enhancement in cemented calcareous sand. Highlights Empirical equation on strength with effects of cement content and curing period Pore volume evolution by hydration reaction in cement treatment Characterization of microstructure change by void ratio Microscopic mechanism of strength enhancement for cemented calcareous sand