PARTIAL REPLACEMENT OF CEMENT WITH COMMERCIAL AVAILABE RICE HUSK ASH IN CONCRETE

Abstract

Natural coagulants are now proving to be good substitutes for chemical coagulants due to their availability, cost effectiveness, nontoxic and biodegradable natures. In this research work, the treatment of highly turbid surface water by coagulation method with sesame and peanut seeds as a natural coagulant has been investigated. This study investigates the potential, suitability, effectiveness and efficiency of sesame and peanut seeds as an environmental friendly and natural coagulant for the treatment of high turbid water, and the effect of each one of the coagulant on the pH of the water, as well as a comparison between the two natural coagulant as which one is more effective in removing the turbidity from water. The sesame and peanut seeds have been used after extraction of the active coagulation component by distilled water and salt solution. The results obtained from the jar test showed that peanut seeds extracted with KCL could effectively remove 88.3% of the 340 NTU turbidity using only dosage of 20 mg/l, while sesame seeds extracted could remove only 79.7% of the 344 NTU turbidity using dosage of 60 mg/l . Moreover, the results showed that the peanut seed is more effective in removing the turbidity from water more than the sesame seeds as it is not that effective in removing turbidity from water. So, it has been demonstrated, in this work, that peanut seed is one of the promising natural coagulants for water treatment Concrete is the world most used construction materials for many structural purposes due to its naturally high compressive strength but production of cement, one of its main ingredients which contribute to the concrete strength, require high amount of energy, costly and release tremendous amount of CO2 to the atmosphere causing global warming and climate change. Thus, by incorporating waste material which has pozzolanic properties as partial replacement of cement can contribute to a lower production cost and environmental friendly. Rice husk has been identified as having the greatest potential as it is widely available and, on burning, produces a relatively large proportion of ash, which contains around 80% - 90% of silica. There are 2 types of silica present in rice husk ash (RHA) which are amorphous and crystalline form. The former being more reactive towards pozzolanic activity and can be achieved through controlled burning. The purposes of this study are to determine the workability and compressive strength of concrete incorporating commercial based rice husk ash as well as the optimum replacement level of RHA based on the concrete compressive strength. Concrete grade M25 were used in this study without the addition of water reducing admixture. Cement is replaced by weight with rice husk ash at 10%, 15%, and 20%. Results showed that the slump value decreases as RHA content increase. Compressive test were done at 7 and 28 days of age. Optimum level of RHA replacement has been identified at 15% where the compressive strength of RHA concrete recorded almost similar value with control concrete. 

Keywords: compressive strength, concrete, optimum replacement level, rice husk ash, slump