This research project aimed to determine the impact of the cement type on the internal damage of concrete exposed to freeze-thaw attack. To identify the inner damage of concrete due to freeze-thaw attack, several test methods are available. In Germany, the CIF-test is widely used, in particular, in the area of water engineering or in the case of technical approvals. However, the impact of the cement type on the internal damage is almost unknown. Previous investigations showed: Concretes containing silica fume in some cases revealed considerably earlier and greater loss of the relative dynamic modulus of elasticity in contrast to concretes containing ordinary Portland cement in the CIF test, although the total porosities were comparable. In those days, this effect was attributed to the amount of freezable water in siliceous gels.
In this research project the additional amount of freezable water in concretes consisting of cement with several main constituents and the influence on the critical saturation of the concrete were examined. Hardened cement pastes were used to determine water vapour sorption isotherms and the type of water binding in the cement matrix (e. g. absorption, adsorption, capillary condensation and chemical bond) was characterized. The internal damage due to freeze-thaw attack was investigated in the CIF-Test.
