Strengthening a thin crust of lightweight pumice aggregate in low strength concrete for tensile and compressive strengths

The primary drawback of lightweight aggregate is its porous surface, which hinders the production of lightweight concrete. Therefore, the process of infusing the porous spaces inside the lightweight aggregate and forming a thin layer around the aggregate results in the production of more robust lightweight concrete. This inquiry aims to highlight the impact of silica fume and Sika level 100T on the tensile and compressive strengths of lightweight concrete. Therefore, we cast and tested a total of 84 lightweight concrete cubes and prisms. In this way, adding 7.23% silica fume to lightweight pumice aggregate concrete raises the compressive strength by up to 22.73% and lowers the flexural strength by up to 5.4%. Also, adding 9.6% Sika level 100T made the lightweight pumice aggregate concrete, which has 7.23% silica fume, 34.57% stronger when it came to compressive strength. By strengthening the bond between the pumice aggregate and the concrete matrix, the addition of 9.6% Sika level 100T significantly boosts the flexural strength by up to 28.12%.