Bond Strength of Steel FRC Repairs to Concrete Substrate: Investigation on Adhesion Strength, Friction, and Bond Enhancing Mechanisms: Fid-Bau Portal

Bond Strength of Steel FRC Repairs to Concrete Substrate: Investigation on Adhesion Strength, Friction, and Bond Enhancing Mechanisms

Rostagno, Giulia / Tingley, Brian / Zanotti, Cristina

Abstract

Abstract Interventions on reinforced concrete structures are increasingly required to compensate the current infrastructure deficit worldwide. Nonetheless, structural and non-structural repairs have exhibited poor effectiveness due to debonding and overall lack of durability. Fiber Reinforced Concrete (FRC) is drawing increasing interest for concrete repair in light of fibers’ ability to enhance concrete durability. Sporadic studies have also shown the potential of fibers to improve concrete-concrete bond, a crucial repair property. However, the information available so far is limited and more comprehensive investigations are required to characterize concrete-FRC bond. A study is presented on the effect of 13 mm long steel fiber reinforcement added to a repair mortar on its shear bond strength to a concrete substrate. 0%, 0.5% and 1% fiber volume fractions are compared and two substrate treatments are applied, namely: substrate left as cast or sandblasted. Cohesion strength and friction coefficients, two parameters inherently characterizing substrate-repair bond, are assessed by means of Modified Slant Shear Cylinder (MSSC) test with variable bond plane inclination, corresponding to variable interfacial shear-normal stress ratio. The beneficial effect of steel fibers on substrate-repair bond and its correlation to substrate treatment is investigated. Cohesion and friction variations are statistically verified through a permutation technique. For plain repair mortars, results are compared with available predictive models.