Theoretical and experimental research on expansive stress in hardened cement paste

In this paper, the formation and development of expansive stress in hardened cement paste (HCP) was studied theoretically, based on the principles of chemical thermodynamics and elasticity mechanics. The expansive stress in HCP was measured by a special test. Using both theoretical and experimental results, the disruption produced by the expansive stress caused by the expansive constituent in cement in HCP is discussed. The effects of free lime on the expansion behaviour of HCP were studied at ambient temperatures. It was found that the expansion behaviour of HCP reflects its inner stress match, which is not only relative to the content and the reactivity of expansion constituent, but also to the cohesive stress of HCP.