The Role of Rice Husk Ash in Enhancing the Fresh Properties, Density, and Compressive Strength of Fly Ash Based Self Compacting Geopolymer Concrete

Abstract

This paper describes the effect of rice husk ash on the fresh properties, density, and compressive strength of fly ash-based self compacting geopolymer concrete (SCGC). Fresh properties were tested by the slump flow test. Density and compressive strength were tested with cylindrical concrete samples. Diameters of samples were about 150 mm and 300 mm high. The variations of Rice Husk Ash (RHA) as Fly Ash (FA) substitution were 0%, 5%, 10%, and 15%. The alkaline activators used Na2SiO3 and NaOH with ratio at 1.0 and a molarity value of NaOH was fixed at 14 M. The water-binder ratio was fixed at 0.3. The dosage of superplasticizer used 1%. The treatment of concrete used ambient temperature. The test results showed that rice husk ash decreased the slump flow; was not affected on the concrete density; and increased the compressive strength of SCGC. The maximum percentage of rice husk ash substitution to achieve the EFNARC slump flow standard was 7.16%. The density of the SCGC was 2076.4 kg / m3 – 2104.3 kg / m3, and classified to the normal concrete. The maximum compressive strength of SCGC was 11.476 MPa at the percentage of rice husk ash substitution about 8.65%.