Early-age Bond Strength Properties between Concrete Substrate and High-performance Fiber Reinforced Mortar for Thin-layering of Bridge Deck Slabs

Deck slabs of highway bridge have been deteriorated due to traffic wheel-loads and environmental factors. To improve the durability of highway bridge slabs, overlaying with steel fiber reinforced concrete (SFRC) are generally implemented. However, in recent years, it is occasionally observed that the overlaying SFRC layer are prematurely de-bonded from the substrate of existing reinforced concrete (RC) slabs. The delamination prevention of the overlaying materials is needed to ensure fatigue durability of the repaired bridge deck slabs. Hence, the study aimed at improving the adhesion of covering layer. In particular, the study focused on the applicability of thin-layering with high-performance fiber reinforced mortar (HPFRM). Direct tensile and shear tests were conducted to examine the peeling resistance of the HPFRM. The experimental study revealed that the bond-strength development at early age is significantly affected by the hardening rate of the adhesive.