Influence of Internal Curing with Lightweight Pumice Fine Aggregate on the Mechanical Properties of Cement Mortars

The cement mortar in the building encounters a problem of curing due to covering mortar under finishing materials such as tiles, stones, and marble. Internal curing is one of the methods for solving this problem. This investigation highlights the impact of internal curing with lightweight pumice fine aggregate on cement mortar's mechanical properties, such as compressive and tensile strengths, and performance, such as density. Thus, the internal cured water-to-cement ratio was studied, which varied from 0 to 21.5%, and the partial replacement of natural sand with lightweight pumice fine aggregate varied from 0% to 16.63%. The results showed the mechanical properties improved with the increased internal water-to-cement ratio. Increasing the internal cured water-to-cement ratio up to 21.52% improves the compressive, split tensile, and flexural strengths of cement mortar up to 77.3%, 56.42%, and 28.71%, respectively. In addition, the partial replacement of natural sand with lightweight pumice aggregate up to 10.9% enhances the compressive, split tensile, and flexural strengths of cement mortar up to 24.2%, 6.1%, and 28.7%, respectively, due to a reduction in drying and autogenous shrinkage.