Chemically treated silica aerogel for the use in lightweight cementitious composite

Abstract

Silica aerogel (SA) has recently gained attention as an alternative to lightweight aggregate in lightweight cementitious composite (LCC). However, it is challenging to ensure homogenous mix of hydrophobicity SA and aqueous cementitious composite. This study investigates a novel chemical treatment of micro-sized SA using methanol solution for incorporation in LCC. Initially, characterization of treated SA was performed and afterwards, it was used as sand replacement up to 80% by volume to obtain the LCC. The proposed treatment method was found effective to overcome the hydrophobic nature of SA temporarily. The incorporation of 80% treated SA caused 45% reduction in density (from 1935 kg/m3 to 1060 kg/m3), 81% reduction in compressive strength (from 36 MPa to 7 MPa), and 31% reduction in water resistance (from 0.76 to 0.52) of LCC, whereas the porosity and water absorption of LCC were increased by 260% and 375%, respectively. However, SA-LCC with 80% treated SA has an acceptable range of properties for non-structural and insulating application, such as low density (1050 kg/m3), sufficient compressive strength (7 MPa), and adequate porosity (59%).