Lateral force microscopic examination of calcium silicate hydrate in rubber ash concrete

Lateral force microscopy was employed to study the influence of rubber ash on the microstructure of concrete. Tapping mode LFM images of microstructure were obtained to observe the calcium silicate hydrate gel in concrete mixes. The roughness parameters and roughness distribution of the scanned area were also determined. The results show that incorporation of hydrophobic rubber ash particles contribute to slight internal curing effect upto 10% substitution. However, at higher substitution (15-20%) the water to cement ratio of concrete gets disturbed and results in gel pores within the concrete matrix. The incorporation of rubber ash weakens the interfacial bonding between different hydration products which results in increased roughness.