Effect of micro-sized silica aerogel on the properties of lightweight cement composite

Lightweight cement composite (LCC) has gained more interest and is increasingly explored by researchers due to its many advantageous properties. Silica aerogel (SA), a synthetic ultralight material, has a nano-porous structure, making it a potential option to be incorporated for LCC. Thus, this research intends to assess the influence of micro-sized SA fines on the properties of cement composite. Specifically, its effect on fresh state properties, porosity, density, compressive strength, rate of water absorption, total water absorption, wettability, and softening coefficient was investigated. The lightweight and micro-size of SA reduced the consistency and slump (up to 90%) of the fresh LCC. Besides that, its hydrophobic nature produced macropores which doubled the porosity in the cement composite. This resulted decrease in density (up to 35%), compressive strength (up to 76%), wettability (up to 21%), and softening coefficient (up to 33%). Water transport properties such as water absorption and rate of water absorption were also increased due to the formation of macropores in the SA cement composite. However, compared to some other LCCs, the cement composite produced with the SA fines in this study in overall exhibited good specific strength.