Geopolymer pavement block from fly ash and palm oil fuel ash

Abstract

This research aims to produce a geopolymer pavement block from fly ash and palm oil fuel ash. The quality of oil palm fuel ash was improved by controlling grinding at 15 minutes. Fly ash to palm oil fuel ash ratio at 90:10, 80:20, 70:30, 60:40, 50:50 and 40:60 by weight were used in this research. 14 molar of sodium hydroxide (NaOH) was used to be alkali solution. The compressive strength was investigated at 7, 14, 28 and 60 days. The mixture which given the compressive strength in the range of 20 - 40 kg / cm2 and contained the most amount of palm oil fuel ash was chosen to produce a geopolymer pavement block. They were prepared with a binder to aggregates ratio of 1:3, 1:5, and 1:7 and with compressed in mold with size of 30x30x5 cm. Compressive strength and The water absorption value of geopolymer pavement blocks were tested at 7 and 28 days. The results showed that palm oil fuel ash can replace 50% of fly ash with providing the compressive strength at 7 days of 21 ksc. The properties of geopolymer pavement block found that the ratio of binder to dust stone was 1: 5 provided the highest compressive strength of 273 and 438 ksc at the age of 7 and 28 days respectively and the lowest water absorption of 11.7 percent at the age of 28 days was found in this mixture.