Research Paper on the of Effects of Sodium Chloride on Bond Strength Between Steel & Concrete

The corrosion of steel strands due to the chloride contamination is one of the most common causes for the degradation of prestressed concrete infrastructure. In this project, an experimental study was performed to investigate the bond behaviors between steel strands and concrete after suffered the chloride corrosion. Total nine central and off-center pull-out specimens with different corrosion levels were prepared and tested on UTM. The effects of corrosion rate, concrete to the steel strands on the bond behaviors of steel strands were studied and compared, in terms of the failure mode, bond-slip relationship, bond strength. In this Project, total Nine cube has casted of size of 15m×15cm×15cm. The grade of the concrete was M40 and Mineral Admixture was fly ash, chemical admixture was super plasticizer and the proportion of the mineral admixture was 20% of the cementious material 0.6 % of super plasticizer. Steel bar of diameter of 8mm and length is 1m is used for providing inside of the cube at a depth of 100mm. Proper Mix design has done and all material required has collected before casting the cube. For casting ,Material is prepared with proportion for first three cube and mixing has done for that three cube and that process has done every three cube and the prepared concrete has filled in cube with proper compaction after determining the slump of that prepared concrete and steel bar is immersed upto 100mm from top in concrete. After painting, testing has been performed that is pullout test and calculation has been done. The result was, bond strength was more than mentioned in the IS 456-2000 and development length was 100mm for every cube that was same as actual provided and development length was 350mm to 400mm for different cube. So we are on safer side as guidelines of the IS code.