MECHANICAL AND DURABILITY PROPERTIES OF SLAG BASED RECYCLED AGGREGATE CONCRETE

Abstract-In this paper, the possibility of using recycled aggregate (RA) and ground granulated blast furnace slag (GGBFS) to produce a structural concrete was studied by compromising strength to a lesser extent. Hence an attempt has been made to study the strength and durability characteristics of the GGBFS-based recycled aggregate concrete. Four different groups of mixes were designed by replacing natural coarse aggregate (NA) 0, 25, 50 and 100% with recycled coarse aggregates. In each group the effect of RA was studied by replacing cement with GGBFS in different percentages from 20 to 50% with an increment of 10%. The effects of RA and GGBFS on fresh and hardened concrete properties were studied and the results were compared with natural aggregate concrete (NAC) and optimum replacement of RA and GGBFS was also found. Experimental results indicate that increase in concrete strength for all NA replacements with RA for GGBFS concrete upto 40% at the age of 90 days and further addition of GGBFS shows reverse trend

Effect of Acidic Water on Strength, Durability and Corrosion of Concrete

Use of poor quality of water in concrete leads to corrosion and ultimately causes failure in concrete, while use of saline water in concrete affects the properties of fresh and hardened concrete. An attempt is made in this study to investigate the effects of various percentage of NaCl present in water used for concreting for different grades of concrete. In this study, specimens of 108 cubes (150 mm x 150 mm x 150 mm), 36 cylinders (300 mm x 150 mm), and 72 cylinders (102 mm x 51 mm) were cast and cured in percentages of NaCl added water to find the workability, strength, durability and corrosion resistance characteristics concrete. The effect of corrosion of steel in the concrete was examined by accelerated electrolytic corrosion method. It was found that, addition of NaCl up to 30% resulted decrease in compressive strength, split tensile strength, higher corrosion rate and chloride ion penetration. However for 20% addition of NaCl these values were found to be moderate.Keywords: Acidic water, compressive strength, durability, corrosion, concrete, RCP