The influence of the expansive site of delayed ettringite formation on the anisotropy of expansion evaluated by mesoscale discrete model

In this study, the effect of the expansive site ratio on the anisotropy of expansion due to delayed ettringite formation (DEF) was numerically evaluated considering creep. In this analysis, aggregates and mortar were separately modeled using 3D-Rigid Body Spring Model. The expansion strain was applied to the expansive site for 200 days. Each analysis was conducted under stress-free and restraint conditions. As a result of the 1 % expansive site, the expansion under restraint condition was smaller than that under stress-free condition. In the case of a higher expansive site ratio, the expansion under restraint condition was larger, and the larger compressive stress was generated in the restraint direction. The reason why the expansion under restraint condition was smaller for the 1 % expansive site case is the less accumulated compressive stress due to the localization of expansion origin. Consequently, the expansion origin may be scattered in the actual phenomenon.