Study of mortar layer property of superhydrophobic metakaolin based cement mortar

The use of alternative materials of cement to prepare cement-based materials has attracted more attention to promote the low-carbon and sustainable development in the field of civil engineering. A clean and sustainable method was proposed of preparing cement mortar using metakaolin as an alternative material with suitable mortar layer property. Superhydrophobic metakaolin (SMK), prepared by using a safe and non-toxic method, was added into cement mortar, and its effects on the of the cement mortar layer was investigated. The SMK was found to improve the thickness of the mortar layer and adhesion ability. The SMK increased the cohesiveness of the cement mortar and improved the stability of the mortar layer, thereby increasing the thickness of mortar layer. The results of TGA and SEM show that the SMK rate with less than 2% promoted the hydration of cement, produced additional calcium silicate hydrate and ettringite, and improved the interface transition zone between the aggregate and the cement mortar layer, thereby improving the cement mortar adhesion ability to the aggregate. It is expected that the proposed method may expand the application of superhydrophobic metakaolin in cementbased materials.