ENGINEERING JOURNAL CHIANG MAI UNIVERSITY

Volume 25, No. 02, Month AUGUST, Year 2018, Pages 231 - 241

Effect of rice husk ash grinding period on autogenous shrinkage and compressive strength of rice husk ash blended concrete

Chananon Singkhasiri and Mongkhon Narmluk

Abstract Download PDF

In this research, rice husk ash (RHA) with different grinding periods was used to replace parts of Portland cement in concrete production, to study its effects on autogenous shrinkage and compressive strength of concrete. Experimental parameters included RHA grinding periods (1 and 2 hour-grinding) and RHA replacement ratios (10% 20% and 30% by weight of total binder). The water to binder ratio was kept constant at 0.42 (by weight). Test results revealed that incorporation of ground RHAs in concrete mixture strongly reduced autogenous shrinkage, as compared to control concrete. Considering the effect of RHA dosage, shrinkage magnitudes at 56 days decreased as the RHA replacement ratio increased. Comparing the effect of grinding period, concrete containing 1-hour grinding RHA exhibited significantly lower shrinkage magnitude, as compared to those containing 2-hour grinding RHA. It was also observed that the use of RHA with longer grinding time (2 hours) promoted better strength gain at early ages, especially when used at high dosage (30%). At long-term, however, the difference in RHA grinding time gave no effect on compressive strength of the concrete.

Keywords

Rice husk ash/ Grinding period/ Autogenous shrinkage/ Compressive strength

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