In the present paper, the addition of silane to improve the properties of mortar was

experimentally investigated. The morphology and microstructure of mortar were

investigated by using both scanning electron microscopy (SEM) and polarizing microscopy

(PM). The results show that silane significantly alters the microstructure of mortar, reduces

the crystallization, restricts the degree of hydration of cement-based materials, and

decreases micro-voids. As a result, silane effectively improves the chemical and carbonation

resistance, as well as the chloride and water penetration resistance of mortar. Results also

indicate that the consistency of mortar was improved but the compressive strength of the

mortar was decreased. Specifically, silane would also be beneficial to the bridging cracking

function to resist crack propagation.