Efficiency of Organic Based Admixed Inhibitors in Combined Ingress Environment

Abstract

In today’s era, reinforced concrete cement is most used constructional material. But durability of reinforced cement concrete (RCC) is major issue. Corrosion in concrete system has become nemesis to RCC structures. Corrosion in rebars in concrete is like a cancer which slowly and slowly affects the structures and eventually results in the failure of the structure. Factors which influences corrosion process are chloride ions and co2 gas present in the environment. Corrosion process forms rust on steel surface, which is non-homogeneous and occupies larger volume than normal steel and results into development of tensile and flexural stresses. This eventually leads to cracking, spalling and delamination of concrete structures. The corrosion inhibitors are the most commonly used preventive measure because of their ease of use. The aim of this thesis study is to examine the performance of two organic: 4-amino benzoic acid (ABA) and tri ethyl phosphate (TEP) compounds as admixed corrosion inhibitor in ingress chloride and carbonation environment. Firstly, both inhibitors were tested in pore solution mimicking concrete environment and then, prismatic concrete specimens of both OPC and PPC were casted and inhibition process of both inhibitor was checked with the help of two electrochemical tests: Linear polarization resistance (LPR) and Half-cell potential (HCP) readings. Concrete cubes were also prepared in order to check free chloride content and carbonation depth. Results obtained from various experiments showed that ABA successfully able to inhibit inhibitor mechanism into PPC concrete system by acting as chelating agent which creates passive layer and prevent corrosion process and similar result was obtained on pore solution. Whereas TEP performed in pore solution and failed in concrete ingress with chloride and carbonation environment due to single functional group and low dosage of inhibitor in concrete system. Free chloride content and carbonation depth tests on cube specimen also indicates similar results as of prismatic concrete specimens.