Effects of Elevated Temperature on Geopolymer Mortar

Sriram Bollineni , N.P.Rajamane

Abstract

The discovery of inorganic polymers in the form of geopolymers is a breakthrough which provides cleaner and eco-friendlier alternatives to Ordinary Portland cement. Published literature shows that using process of alkaline activation, materials rich in alumina and silica, can be transformed into a cement to function as geopolymeric material (which is basically an alumino-silicate amorphous system) to act as a binder in a way very similar to OPC. This aspect was taken up for study in the present experimental investigation and with specific aim of filling the current knowledge gap in understanding the behaviour of geopolymers under elevated temperatures. The geopolymeric mortar mixes with fly ash and GGBS as Geopolymeric Source Material (GSM) and river sand as inert filler material were prepared to examine the refractory properties of geopolymer binders. Alkali Activator Solution (AAS) was made from a mixture of sodium hydroxide solution (having molarity of 5) and sodium silicate solution (with molar ratio SiO₂/Na₂O being 2.1). Parameters like weight loss and compressive strength were studied after the specimens were subjected to different temperatures i.e. 200⁰C, 400⁰C, 600⁰C and 800⁰C. The results of the geopolymer mortar were compared with the addition of ceramic additive.