DUCTILITY ENHANCEMENT OF RC BEAMS STRENGTHENED WITH STRAIN HARDENING CEMENTITIOUS COMPOSITES

摘要

Ultra High-Performance Strain Hardening Cementitious Composites (UHP-SHCC) is a newly developed construction material, has large advantages on large strain capacity as well as high compressive and tensile strength, which is useful for strengthening or repair concrete members. An important obstacle needs to be studied, is the strain localization occurs in the UHP-SHCC strengthening layer around the substrate concrete cracks, which severely limits the ductility of the strengthened beam. In the present study, five specimens were tested experimentally, one as a control and four strengthened with variable reinforcement ratios embedded in the strengthening layer. The recorded tests showed that it is sufficient to use 1.2% additional reinforcement ratio embedded in the strengthening layer for beams strengthened with UHP-SHCC to eliminate the observed early strain localization and to gain adequate ductility. Another important conclusion is the strengthening of RC structures using an unreinforced UHP-SHCC layer may lead to a brittle failure.