PSI - Issue 70

Maahira M. et al. / Procedia Structural Integrity 70 (2025) 642–649

648

to the uniform distribution and reactivity of binder solution in GGBS (Fig.7). In oven cured aggregate, 10M aggregate resulted in 21% lower impact value compared to 8M which is due to the accelerated formation of hydrated products and pore filling effects under the influence of oven curing. The optimum molarity is taken as 8M keeping crushing value, economy and energy usage as the selection criteria. 4. Casting of concrete using prepared Artificial Aggregate Geopolymer Concrete of M30 grade was cast using the 8M oven cured aggregates as it gave best results among the three Molarities 8M,10M and 12M.The properties of the geopolymer concrete cast using artificial aggregates such as compression strength, tensile strength and water absorption were studied .These properties were then compared with the properties of Geopolymer concrete cast using conventional aggregate so as to see whether the concrete prepared using these aggregate can replace the concrete prepared using conventional aggregate. The Grade of M30 concrete is designed with 10M solution, La/ash ratio 0.4, NaOH/Na 2 SiO 3 -2.5, 16mm size coarse aggregate. The mix proportion (GGBS:FA:LA)- 1:1.5:3.3 4.1 Casting of cube and cylinder Among the manufactured artificial aggregates oven cured 8M aggregate was used to cast concrete with 100% replacement of conventional aggregate. The aggregates were sieved using various sizes of sieves ranging from 4.75mm 10mm, 12.5 mm, 16 mm and 20mm.After sieving 16mm aggregates were selected for concrete casting. M30 grade geopolymer concrete was cast using alkaline solution of 10M mix. The liquid alkaline solution to ash ratio (i.e. L/A ratio) is taken as 0.4. The ratio of NaOH sodium hydroxide to Na2SiO3 sodium silicate is 2.5. The 10 M NaOH solution is prepared by using 400gm of NaOH pellets in 1 litre of water. Then the concrete was casted in the ratio of 1:1.5:3.3 in which 1 indicates GGBS, 1.5 indicates the fine aggregate (i.e. M-sand) and 3.3 indicates coarse aggregate.

Fig.8 Concrete Cubes and cylinders samples

The dry material were mixed first then the prepared alkaline solution was slowly added to the dry mix in the mixer machine. The mixer machine allowed to rotate till proper mixing is ensured. Then the concrete is placed in 100 mm cubes and 100 mm diameter cylinders (Fig. 8). The samples are demoulded next day and were left for ambient curing. After 3 days of ambient curing the samples are tested for compressive strength, split tensile strength and water absorption.