Strength Properties of Foamed Concrete Containing Blends of Rice Husk Ash (RHA)

Abstract

The present study was planned to study the influence of Rice Husk ash (RHA) on fresh and hardened properties of foamed concrete. The percentage replacement levels of RHA for fine aggregates (FA) were 0%, 5%, 10%, 15% and 20%. Production of light weight concrete was carried out with foam which was produced indigenously using a foaming agent (Foamtech). The theoretical density of foamed concrete containing 0% replacement level of Rice husk ash (RHA) was kept to be equal to 1300 ± 50 kg/m3. The actual density observed for foamed concrete containing 0% replacement level of RHA during experimental analysis was 1317 kg/m3. At curing age of 7, 14, 28, 56, and 90 days, the hardened foamed concrete cube specimens of size 100 mm × 100 mm × 100 mm were evaluated for compressive strength and 150 mm × 300 mm for split tensile strength. At a curing age of 28 days, the cube specimens were also examined for water absorption and dry density. For all of the foamed concrete mixes, the cement and fine aggregate content were kept the same. The water-cement ratio was maintained at 0.5. The only difference among all the mixes was the replacement level of RHA 5%, 10%, 15% and 20%. The amount of foaming agent was varied according to the replacement levels of RHA to ensure good workability of paste. All the results of various properties were compared with the control mix. It may be noted that 0% replacement level of RHA with FA has been considered a control mix. The maximum and minimum compressive strengths, split tensile strengths and dry densities were shown by control mix and mix containing 20% replacement level of RHA respectively. On the other hand, the minimum and maximum water absorption capacities were shown by control mix and mix containing 20% replacement level of RHA respectively.