Comparison of bond efficiency of various coating materials

The paper reports an experimental research investigation carried out to compare the bond resistance and efficiency of various coating materials, including epoxy, which were sourced locally. Thirty-four full size beams of varying lengths and sectional dimensions, with lap spliced bars in constant moment region were cast and tested in a four-point bending system. Three varying high yield diameter bars 16 mm, 20 mm and 28 mm were coated with various coating materials such as epoxy, chlorinated rubber, tyrolin, vinyl chloride and zinc ethyl silicate in an attempt to find a cheaper but effective coating material than epoxy. The ultimate moment from the tests were used to determine the stress developed in the steel rods. The bond efficiency, i.e. the ratio of test bond stresses and the theoretical bond stresses was used for the comparison of the various coating materials. The bond resistance and efficiency of vinyl chloride coated bars were found to be higher than that of epoxy and other materials, in all the beams tested. Statistically, there appear not to be significant difference between the bond efficiency of epoxy and vinyl chloride.