**3.1 Compressive strength**

The obtained compressive strength values for mixes G10A, G20A, G30A, G40A, G50A and G0A are respectively 30.88, 34.22, 37.78, 41.78, 36.22 and 26.5 MPa and the compressive strength values for mixes G10A', G20A', G30A', G40A', G50A'and G0A' are 30.56, 33.85, 36.65, 41.52, 38.5 and 27.76 MPa respectively. The values are plotted in **Figures 7** and **8**.

The test results yield an inference that addition of GGBS in fly ash increases the compressive strength upto 40% replacement [13, 14]. The presence of calcium content in GGBS seems to be a real contributor for increase in strength upto 40% after which microstructure gets altered causing decrease in compressive strength. The compressive strength of control mix was low compared to other mixes using GGBS.

#### **Figure 7.**

*Comparison of Compressive strength of GPC by ambient curing.*

**Figure 8.** *Comparison of Compressive strength of GPC by Wetting and drying cycles.*
