Strength and durability studies of fly ash concrete in sea water environments compared with normal and superplasticizer concrete

Abstract

The objective of this work was to get a holistic idea about the behavior of fly ash concrete exposed to sea water environments. Concrete mixes namely Normal Concrete (NC), concrete with fly ash and superplasticizer (FA) and concrete with superplasticizer alone (SP) were cast and immersed for a year to find out the strength, durability, biofilms formation and chemical composition. The pH, compressive strength, Half Cell Potential (HCP), Rapid Chloride Permeability Test (RCPT) and carbonation test showed better results in FA. Epifluorescence micrograph observed less number of fluorescing cells. Analysis of phase images of Lock- in thermography reveals the phase angle differences of concrete samples indicating the least deterioration on FA concrete. After 280 days of exposure, XRD showed higher loss of calcium elements in NC and SP concrete compared to FA. LRS also showed that Raman intensities of NC and SP were drastically reduced. However, LRS and XRD results of FA confirmed formation of more cementitious products due to secondary hydration explaining the reason for increased compressive strength.