THE INFLUENCE OF CURING CONDITIONS WITH LOW NAOH MOLARITY ON THE MECHANICAL PROPERTIES OF GEOPOLYMER CONCRETE

PENGARUH KONDISI CURING DENGAN MOLARITAS NaOH RENDAH TERHADAP SIFAT MEKANIK BETON GEOPOLIMER

Abstract

This study aims to analyze the effect of curing conditions and low NaOH molarity on the mechanical properties of fly ash–based geopolymer concrete as an environmentally friendly alternative to conventional concrete. The NaOH molarity variations used were 6 M, 8 M, and 10 M, with two curing methods: oven curing at 90°C and 120°C, and ambient curing. Compressive strength tests were conducted at 3, 7, and 28 days. The results showed that the highest compressive strength was achieved under oven curing at 90°C, reaching 40.514 MPa at 28 days, while the lowest value of 7.992 MPa occurred under ambient curing. The increase in compressive strength from ambient curing to oven curing at 90°C reached 173.82% at 3 days and 135.16% at 28 days. Furthermore, increasing the NaOH molarity from 6 M to 10 M significantly improved compressive strength, with an average increase of 32.25% at 3 days and 44.84% at 28 days. Overall, oven curing at 90°C provided the most optimal results, while curing at 120°C produced slightly lower performance. This study highlights that controlling curing temperature and activator molarity plays a crucial role in optimizing the strength of fly ash–based geopolymer concrete.