The influence of lithium silicate impregnation on the properties of surface layer of cementitious composites

The degradation processes in surface layers of cementitious composites can be mitigated either by optimizing of the material or by applying surface protection. In this paper, the effect of lithium silicate (LS) sealer is investigated. Water absorbance is studied on standard cement mortar; frost resistance and porosity are examined on two types of concrete (C30/37 and C50/60). The results indicate that LS impregnation improves the water absorbance only slightly and only in the case of short exposure to water; water absorbance was reduced by 15-25% immediately after applying the LS sealer, but the effect was negligible (2-8%) after 24 hours of immersion in water. Frost resistance was not affected by LS impregnation, but a significant improvement of mechanical parameters (flexural tensile strength and weight loss after 50 freeze-thaw cycles) was observed. The resistivity of the concrete surface was increased by LS impregnation by 36-40%, indicating the improvement of quality of the surface layer, while the porosity was practically unaffected