INVESTIGATION OF SETTING TIME AND FLOWABILITY OF GEOPOLYMER MORTAR USING LOCAL INDUSTRY AND AGRICULTURE WASTE AS PRECURSOR IN INDONESIA
Geopolymer is a renewable construction material that reduces dependence on ordinary portland cement (OPC), where OPC manufacturing impacts carbon dioxide (CO2) emissions. The main aspect of geopolymers being studied is the precursor of pozzolanic material, used as a cement substitute because it contains aluminosilicate (Si-Al). Polymerization occurs between the precursors, reacted by alkaline activator solution (AAS). Sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) were used as AAS. In this study, local precursors from industrial waste and biomass were utilized. Fly ash was employed as a reference in the precursor by 5% - 10% substitution of glass powder, rice husk ash, bagasse ash, and palm shell ash. Moreover, 2% superplasticizer and 5% extra water were used to increase the flowability of fresh geopolymer. Tests were carried out on the setting time of paste, flow table, and compressive strength of geopolymer mortar. The tests were on the initial setting time of 25-75 minutes and the final setting time of 40-115 minutes. The setting time results revealed that the time of each substitution accelerated geopolymerization due to the substitution of precursors containing higher CaO and SiO2. Setting time and flowability/workability had a linear regression correlation (R2) of 0.95, with the flow table ranging from 180-250 mm. The compressive strength ranged from 25.88 – 36.36 MPa through a curing temperature of 70oC for 24 hours, followed by curing at ambient temperature for up to 28 days.
- 2021-11-30 (2)
- 2021-11-30 (1)