Mechanical properties of geopolymer paste with fly ash variation

This paper presented mechanical properties of geopolymer paste with fly ash variation. Mechanical properties were assessed by compressive and setting time test. Fly ashes were obtained from three different places namely Paiton, PT Petro Kimia Gresik (PKG) and Fly Ash were sold in the local market of Malang. NaOH (Sodium Hydroxide) with concentration of 10 Molar and Na2SiO3 (Sodium Silicate) were used as alkali activators with ratio activator of 2. Percentage of fly ash and alkali used is 75% and 25%. Compressive strength test was conducted on binder with the age of 7,14,21,28 days, while setting time test was performed on fresh geopolymer paste. The results showed that fly ash obtained from the local market has the highest compressive strength with the value of 48.45MPa at 28 days. However, faster setting time will deliver higher compressive strength of geopolymer.