Pore structure and hardened properties of aerogel/cement composites based on nanosilica and surface modification.

• ACCs preparation without aggregate floating and aggregate size effect. • The compatibility improvement between aerogel slurry and cement matrix. • Optimization of matrix by using nanosilica and high-temperature curing system. • Correlation between pore structure and properties. • The realization of coordination between thermal insulation and mechanical properties. Lightweight aerogel/cement composites (ACCs) were prepared by introducing a silane coupling agent modified aerogel slurry into a nanosilica enhanced cement paste. The effect of the modification on the pore structure and hardened performance of ACCs was investigated. The results indicate that nanosilica can enhance the matrix. Surface modification of aerogel results in better compatibility and facilitates the preparation of ACCs with synergistic mechanical properties and thermal insulation properties. An ACC with a thermal conductivity of 0.067 W/(m·K), a compressive strength of 1.2 MPa and a density of 390 kg/m3 was successfully prepared by 66 vol% replacement of cement paste with the modified aerogel slurry. In addition, the total porosity and average pore diameter of the composite are 72.8% and 170.9 nm, respectively. [ABSTRACT FROM AUTHOR]