EXPERIMENTAL PROGRAM
1. Materials
43 grade OPC cement having specific gravity of 3.15% was used for cement concrete. For geopolymer concrete siliceous pulverized fly ash obtained from Hi-Tech private limited, Tuiticorin, India, having a specific gravity of 2.2 and low calcium, ground granulated blast furnace slag of specific gravity 2.9 obtained from the, JSW Steel Limited, Salem. India, were used as the source material.Table 1 gives the oxide composition. 97% purity sodium hydroxide (NaOH) pellets and sodium silicate (Na2SiO3) with 28.13% Na2O, 28.13% SiO2, and 40.74% H2O were used. For the NaOH solution, NaOH pellets were mixed with distilled water and stirred until all the pellets were completely dissolved. The solution was then left for …show more content…
Fly ash / GGBFS and aggregates were mixed homogeneously and then the prepared alkaline solutions were added to it. The mixing of total mass was continued until the mixture become homogeneous and uniform in colour.

2.4. Curing Conditions
The specimens were casted and allowed to set for 24hours. The specimens were then removed from the moulds and kept wrapped in polythene sheets till testing at ambient temperature.
3. TESTS AND RESULTS
3.1. Compressive strength
The compressive strength resultsat 7th day and 28thday, according to IS 516-1959 are shown in Fig.1. 20% increase in the compressive strength was observed for geopolymer concrete with same mix proportion compared to M30 OPC concrete. Results show that geopolymer concrete attains the target strength at 7th day itself.

Fig.1: Compressive Strength Results
3.2. Splitting tensile strength
A direct measurement of ensuring tensile strength ofconcrete is difficult. One of the indirect tension testmethods is split tension test. The split tensile strength testwas carried out on the compression testing machine. Thecasting and testing of the specimens were done as per IS5816: 1999. The results as in Fig.2show that there is an increase of 10.2% in the tensile strength for GPC in comparison with M30 control