Effect of Using Soap Nut as Natural Foaming Agent on Mechanical Properties and Pore Distribution of High Strength Aerated Concrete

Aerated concrete is a type of concrete that contains pore in its matrix structure. This pores could provide spaces for water absorption which makes aerated concrete more durable toward freeze-thaw cycle. Many methods have been studied in forming an aerated concrete and using soap nut as aerating agent is more sustainable than other chemically formulated agent. Forming of pore inside concrete not only improve freeze-thaw cycle durability but also as places to store healing agent in concrete. This is important in developing a self-healing concrete especially a microbial induced healing. This paper aims to study the effect of using soap nut in high strength concrete. Four types of high strength concrete samples were prepared which are Control sample, AE2 with 2% of aerated soap nut, AE4 with 4% of aerated soap nut and AE6 with 6% of aerated soap nut. Total of 3nos. of 100mm cubes and 3nos. of 50mm cubes from each type of samples were prepared. Cubes samples of 100mm dimension were tested for water absorption and compressive strength while cube samples of 50mm dimension were split and analysed for pore distribution. The results showed that increase in addition of soap nut in concrete mixture resulted in decrease of compressive strength but minimal effect on its water absorption rate. Pore formation and dispersion were optimum in concrete with 4% and 6% inclusion of soap nut. In conclusion, 4% of aerated soap nut in high strength concrete present the optimum characteristic in producing well-dispersed pores of high strength aerated concrete.