Feasibility and corrosion inhibition efficacy of zeolite-supported lauric acid imidazoline as corrosion inhibitor in cementitious mortar

Abstract

A zeolite supported organic corrosion inhibitor with high loading efficiency was obtained by loading a synthesized lauric acid imidazoline (LAI) in the Ca2+-exchanged zeolite (Ca2+-zeolite) framework. The influences of the as-prepared Ca2+-zeolite supported LAI (Ca2+-ZSLAI) as an admixture in porosity and compressive strength of the resulting cement mortar were examined. The protective effect of Ca2+-ZSLAI against steel corrosion of steel-mortar immersed in NaCl solution was discussed upon. The properties of the steel reinforced mortar incorporating Ca2+-ZSLAI was compared with the reference mortar specimen without corrosion inhibitor and the specimen solely with LAI or Ca2+-zeolite. The steel corrosion resistance performance of Ca2+-ZSLAI was revealed by electrochemical testing on steel reinforced mortar during the chloride ions accelerated corrosion test. Experimental results revealed that mortar with 6% of cement replaced by Ca2+-zeolite saturatedly supported LAI as corrosion inhibition additive presented 14% higher compressive strength and 23% lower total porosity compared to the reference mortar. Besides, such dose of inhibitor could retain 92% corrosion inhibition efficiency of the embedded steel after 142 immersion days. The excellent corrosion resistance efficacy of Ca2+-ZSLAI was ascribed to the chloride “binding capacity” of the densified mortar substrate improved by the filling and pozzolanic effect of Ca2+-zeolite and the chloride “barrier capacity” of the protective interfacial film deposited by the LAI released from the Ca2+-zeolite carrier.