ABSTRACT
A portion of the workshop floor of the Structural Engineering Research Centre, Madras, which was built more than 15 years back, was used for the study. An area of about 2.5 m×2.5 m of the floor where heavy loads were expected to move, was chosen for the experimental overlay. The compressive strength of this concrete flooring was found to be 30 N/mm2 from Schmidts hammer tests. The top portion of the concrete floor was chipped off to a depth of 55 mm to expose the hard concrete inside. The bottom and the side faces of the trench were cleaned with a wire brush and compressed air was used to blow off all the loose particles. An epoxy resin recommended for bonding hardened concrete to fresh concrete was applied before placing a 40 mm thick M30 grade concrete mix in the trench. The top surface of the concrete was rendered rough to obtain better mechanical bond between this concrete and the epoxy concrete overlay to be laid on top of it. After 28 days of curing in moisture, an epoxy concrete overlay was laid in four sections. The geometry of each section is given in Fig. 8. Flyash:sand:aggregate:epoxy resin was 1:3:4.7:1.3 which possessed a compressive strength equivalent
