High-temperature strengthening of Portland cementitious materials by surface micro-ceramization

This work prepares a novel cementitious material with high-temperature strengthening by adding titanium diboride (TiB₂) powders into Portland cement. The influences of TiB₂ on the physicochemical properties of paste samples before and after high-temperature treatment (the maximum is 900 °C) are investigated. Results indicated that the pore structure of hardened paste is refined after curing because of the filling effects of TiB₂ micron powders. During the heating, the ceramic phases are formed from the outer layer to the inner layer in the hardened paste because of the high-temperature oxidability of TiB₂, strengthening the matrix significantly (the highest compressive strength value increase is about 55.2% compared to the initial value). A random forest algorithm model analyses the contributions of matrix compositions and porosity on the compressive strength of hardened paste. The potential reaction mechanisms among the TiB₂ and the main hydrates at high temperatures are suggested.