Use of high strength SHCC for the repair of concrete structures with significant steel reinforcement corrosion

Abstract

Steel corrosion is a major cause of deterioration of concrete structures, which can lead to significant loss of steel area that affects structural safety. The most common repair approach is to splice a new piece of steel to the corroded reinforcement, which is time and cost consuming, as a large volume of sound concrete on both sides of the corroded steel has to be removed to provide sufficient lap length for stress transfer. The present study focuses on a new repair methodology based on the use of high strength Strain-Hardening Cementitious Composite (SHCC). With the SHCC providing tensile load carrying capacity to compensate for the steel loss, splicing of additional steel reinforcement is no longer necessary. The amount of concrete removed to provide the bond length is then significantly reduced. In this paper, the design of high strength SHCC is first discussed. Then, reinforcements with reduced area over part of their length are embedded inside SHCC blocks with cross-sectional area representative of typical concrete patches and having different bond lengths on both sides. Direct tension test is then performed to investigate the feasibility of the SHCC to recover the load carrying capacity. The results demonstrate the potential of a new repair technique which is more efficient and less costly.