Study of mechanical, acoustic, and microstructure properties of lightweight mortars produced with expanded clay

The inclusion of alternative materials in concrete production is very efficient, having a sustainable bias and improving the main properties of concrete. Expanded clay has been used to produce mortar and concrete, partially replacing the aggregate with the main purpose of reduces specific mass and the weight of the structure, also improves acoustic and thermal characteristics. This study proposes the use of expanded clay to a lightweight laying and coating mortar compared to conventional mortars. It was investigated the influence of expanded clay as a substitute for conventional fine aggregate in mortars in ratios of (5, 10, 15, and 20) %. Tests were carried out in the fresh (consistency index, mass density, incorporated air, and water retention) and hardened states (flexion tensile strength, axial compression, apparent mass density, and potential tensile adhesion strength) based on the Brazilian Technical Standards Association (ABNT). The microstructure was also investigated using a scanning electron microscope (SEM). The results show that the replacements improved the strength of the mortars, being 20% higher than expected by the standard. Expanded clay is a sustainable alternative and adds new properties (thermal and acoustic) to mortars.