Effect of pore structure on salt crystallization damage of cement-based materials: Consideration of w/b and nanoparticle use

In this study, the influence of pore structure on the extent of calcium nitrate salt crystallization damage on mortar samples was examined. The pore volume and structure was altered by varying water-to-binder ratio and by adding nanoparticles. The results show that calcium nitrate salt exposure induces cracking in mortar samples and that more damage was observed at higher water-to-binder ratio and higher rate of nanoparticle use. It is proposed that the refined pore structure induced by nanoparticle use can result higher salt crystallizing pressure. Thus, cementitious structures that are expected to be exposed to salt crystallization should be designed to meet strength needs by lowering water-to-binder ratio < 0.40. When using nanoparticles of the type examined here, limiting their use to rates of < 5% by mass of cement and use of water-to-binder ratio < 0.40 appears to be prudent.