SEM images were used to explore the microstructure of the corresponding specimens. SEM images of the specimens
with and without SCBA at the age of 56 days were investigated by means of SEM methods. Figure 6 shows the SEM
photograph of BA0. It can be seen that a lot of hydration products – like C-S-H gel, Aft crystals, and several pores
were formed on the surface of BA0. Figure 7 shows the SEM images obtained for the specimen of BA10. Observations revealed that the rough surface of the mixture of BA10 showed to contain C-S-H gel, Aft crystals, and also narrow pores. However, the differences in the microstructural features between the specimens without and with bagasse ash are not obvious. With the addition of 10 % SCBA to the mixture, there takes place the reaction of the portlandite produced by the hydration of the calcium silicates in the cement with the silica and alumina reactivates in the pozzolanic material. This reaction produces C-S-H gel, which grows into the capillary spaces. Hence, the paste structure tissue became dense. The observations are consistent with those of water absorption, initial surface absorption, compressive strength, and RCPT results.