Evaluation of bagasse ash as corrosion resisting admixture for carbon steel in concrete

Abstract

PurposeUtilization of industrial and agricultural waste products as cement replacement materials in concrete technology has been an interesting subject of research for economical, environmental, and technical reasons. Portland cement incorporating these cement replacement materials improves corrosion resistance of carbon steel. Sugar cane bagasse is considered as waste in sugar mills and dumped in open space or used as fuel for boilers. The main purpose of the study is to investigate corrosion performance of reinforcing carbon steel in bagasse ash (BA) blended cement concrete and compare it with control concrete.Design/methodology/approachBA is prepared by burning boiler‐fired ash at a controlled temperature of 650°C for 1 h and cooled. The ash is then ground to a fineness of 46 μm as Pozzolanic material and blended in concrete in various cement replacement levels. The corrosion behaviour of carbon steel in BA blended concretes exposed to alternate dry‐wet cycles in 3.0 percent NaCl solution for 18 months was studied using gravimetric weight loss, linear polarization, and electrochemical impedance measurement techniques. The resistance to chloride ion penetration of BA blended concretes after 28 and 90 days and compressive strength of BA blended concrete cubes after 7, 14, 28, and 90 days curing also was evaluated.FindingsThe experimental results indicated that the corrosion rate of reinforcing steel and chloride penetration were significantly reduced, and compressive strength was increased, with the incorporation of BA up to 20 percent replacement in concrete. It was observed also that a relatively good correlation between linear polarization and impedance measurements with respect to corrosion current values on the reinforcing steel within BA blended concretes.Originality/valueBA may be considered as a better substitute than other mineral admixtures for durable concrete structures. The study fulfilled the objective of the investigation and contributes to research on corrosion protection of carbon steel in concrete.