This article aimed to research the effect of organic silicon on the density, mechanical strength, water absorption, porosity, and crack resistance of cementitious construction materials. Modified cement mortar was prepared by adding different amounts of organic silicon into control cement mortar. Mechanical strength was evaluated using bending and compressive strength tests. Porosity was evaluated to assess the inner structure of cement mortar. Furthermore, the micromechanism of modified cement mortar and control cement mortar was explored usin...