The effect of silica fume admixture on the compressive strength of the cellular lightweight concrete

Abstract

Foam concrete has practical and economic advantages in construction, including reducing the structure's weight by building foundations. The market demand for foam concrete such as Cellular Lightweight Concrete (CLC) block has increased recently. One way to reduce the density of CLC is to add air pores to the cement paste or mortar mixture. However, the addition of pores can reduce the strength of lightweight bricks. Therefore, there is a need for innovation to improve the quality of CLC block by replacing some of the cement with other added materials. This study aims to obtain a good quality CLC block using silica fume to replace partial cement in a mortar mixture. The specimens are a CLC block measuring 10 cm wide, 20 cm high and 60 cm long. Variation of mortar mixture using silica fume percentage of 0%, 0.5%, 1%, 5%, 10% and 15% of cement weight. The output data generated from this sample are compressive strength, displacement, stress, strain and the modulus of elasticity. The test results obtained the optimum CLC compressive strength of 1.03 MPa at 10% silica fume composition. This optimum compressive strength of CLC was simulated using the LUSAS finite element analysis to obtain the displacement and stress-strain patterns. Based on the LUSAS numerical analysis, the optimum compressive strength of the CLC block was 1.06 MPa. This study shows that adding 10% silica to the CLC mortar mixture can increase the compressive strength by 81.25% compared to mortar without silica fume.

Keywords

• Cellular lightweight concrete
• Compressive strength
• Foam concrete
• Silica fume
• LUSAS