Compressive strength of foam geopolymer made from fly ash and aluminum powder

Abstract

This paper examines the compressive strength of foam geopolymer made from fly ash and aluminum powder at 0, 0.4 %, 0.8 % and 1.0 % by mass of the fly ash. The 5 mole of sodium hydroxide alkali was used to stimulate the geopolymers. A liquid-to-fly ash mass ratio (L/FA) of 0.5 was used for all mixes. Foam geopolymer were oven drying at 55 °C, 60 °C, 65 °C, 70 °C, and 75 °C for 24 h. The foam geopolymer with a dry unitweight of approximately 1,700 – 1,800 kg/m3 was mixed with the aluminum powder of 0.4 - 1.0 % w/w. The testing results found that the compressive strengths were between 2.01 MPa and 6.6 MPa, which the compressive strength increased as drying temperature increased from 55 °C to 60 °C. The water absorptions were between 10 % and 21 % by weight, which the water absorption rate increased as the dry unitweight decreased