The porous surface of lightweight aggregate is the main weakness property for producing lightweight concrete. Thus, the filling porous in lightweight aggregate and creating thin layer surrounds aggregate produce stronger lightweight concrete. Therefore, the influence of silica fume and Sika level 100T on the tensile and compressive strengths of lightweight concrete is highlighted in this investigation. For this reason, it was cast and tested 84 lightweight concrete cubes and prisms. It was found that the compressive strength improves up to 22.73% and 34.57% due to inclusion 7.23% of silica fume and 9.6% of Sika level 100T, respectively. While the flexural strength enhances up to 5.4% and 25.72% due to adding 7.23% of silica fume and 9.6% of Sika level 100T, respectively. In addition, the curve fitting software was used in the formulation of the proposed models to verify this improvement and it was found that the proposed model has a good agreement with the test results.