A new hypothesis for early age expansion of cement-based materials: Cavitation in ink-bottle pores

Early age shrinkage behaviors of cement-based materials frequently show an expansion, which is mainly explained by influences of bleed water, hydration products, and temperature. This work measures autogenous or plastic shrinkage, temperature, and capillary pressure of pastes to study the mechanism of the expansion. Results show that the expansion can occur in absence of reabsorption of bleed water, formation of expansive products, and thermal expansion, and further indicate that the expansion occurs during cavitation of the paste. A new hypothesis based on stress release caused by the cavitation in ink-bottle pores was proposed to describe the mechanism of the expansion.

Automated summary

Early age shrinkage behaviors of cement-based materials are influenced by bleed water, hydration products, and temperature. However, it has been discovered that expansion can still occur without the reabsorption of bleed water, formation of expansive products, and thermal expansion. This is because the expansion happens during cavitation of the paste, which is caused by stress release.