Abstract:
This thesis aimed to study the effects of the using Rice Husk Ash (RHA) as partial replacement in cement on the compressive strength of motar, compressive strength and permeability of concrete under pressure mold.
Currently, there are 2 types of RHA from A.T. Biopower Co. Ltd. in Phichit province: a) Ground Rich Husk Ash (GRHA) and b) Unground Rice Husk Ash (URHA). These two types of RHA are mainly used to partially replace portland cement at 10% and 20% by weight of binder. The compressive strength of motar is determined based on its saturated stage at 3, 7, 28, 60 and 90-day duration. For the compressive strength of concrete on the other hand, it is determined at 7, 28, 60 and 90 days. Lastly, the permeability of concrete is determined at 28 and 90 days.
In this study, it was found that GRHA could produce highly pozzolanic reaction and the pozzolan materials passed the ASTM C 618 quality standard. The compressive strength of motar with control flow and control water-cementitious material ratio which were determined at the drying stage of 3, 7, 28, 60 and 90 days showed that the replacement of GRH in portland cement type I at the rate of 10% gave higher strength than standard motar. In terms of the development of compressive strength of standard concrete under pressure mold (CON-P), the result yielded compressive strength higher than the normal casting of 48% at 90 days duration. In the same manner, the replacement of GRH in concrete under pressure mold (GRH-P) gave higher strength of concrete than the concrete under pressure mold URH (URH-P) and CON-P. The replacement of GRH-P 20% by weight in portland cement could produce higher compressive strength than the replacement of GRH at 10%. It was also found that by using concrete casting pressure compressed, the water permeability decreased and the replacement of GRH-P 10% by weight in portland cement developed concrete with a lower permeability values than URH-P and CON-P.