This study is about the addition of furnace incinerated Rice Husk Ash into concrete with fly ash. The primary objective of this research work is to investigate the mechanical properties like compressive strength and to reduce the overall cost of construction. RHA and fly ash was used to replace cement partially at different rates, fly ash is used at the rate of 0%, 5% and 10% and RHA at the rate of 5% and 10%. The physical properties of RHA were determined by particle size analyzer. Pozzolanic reactivity of RHA is dependent on silica form. The silica form in RHA is determined by incineration process. To decide it is in crystalline form optimum cement replacement ratio of RHA and fly ash found at 5%+5%. In this investigation firstly two lower grades concrete M-15 and M-20 were prepared and the best result was found with M--15 grade of concrete, then experiment were done with higher grades i.e. M-30 and M-35 grades and there is slight increase in compressive strength in higher grades. CASE-I, for M-15 Grade of concrete during the experiment it has been noticed that the maximum 28 day compressive strength of nominal cube obtained was 21.1 N/mm², for a mix with RHA and fly ash of 5%+5%, 26.7 N/mm² compressive strength is found, and hence an increase in strength over normal concrete is 26.54% when we added RHA. CASE-II, For M-20 Grade of concrete, during the experiment it has been noticed that the maximum 28 day compressive strength of nominal cube obtained was 27.2 N/mm², for a mix with RHA and fly ash of 5%+5%, 34.5N/mm² compressive strength is found, and hence an increase in strength over normal concrete is 26.83% when we added RHA. In case of higher grades in CASE-III, there is 11.33% increase in compressive strength of M-30 grade concrete and in CASE-IV, there is 12.49% increase in compressive strength of M-35 grade concrete. It has been found during experiments that as the percentage of RHA increases the compressive strength increases initially, on further increase in its percentage compressive strength will be reduced....
Authors: Nitesh kushwah, Sandeep k Shrivastav.