AN EXPERIMENTAL STUDY ON HARDENED PROPERTIES OF CONCRETE SPECIMENS AT INTERFACE OF OLD AND NEW CONCRETE
Keywords:
Substrate, Epoxy resin, Splitting tensile, Slant shear, FlexureAbstract
An experimental study was performed to evaluate the hardened properties of concrete specimens at interface of old and new concrete, using as cast substrate surface and a commercial epoxy resin based bonding agent under different laboratory tests. Laboratory tests, including splitting tensile strength (bond strength in tension), slant shear strength (bond strength in shear) and flexural strength (bond strength in flexure) tests were conducted. The influence of the strength of concrete on the hardened properties of old and new concrete interface, the substrate(old) concrete was kept unchanged with a compressive strength of 20 MPa. On the other hand, two different concrete mixes, with compressive strengths 25 MPa and 30 MPa were used for the new concrete. Splitting tensile half
specimens were cast and surface left as cast. After the age of 28, 56 and 84 days, the new concrete was added thus make in it as full cylinder. Slant shear half specimens were cast and surface left as cast. After the age of 28, 56 and 84 days, the new concrete was added thus make in it as full prism. Splitting tensile half specimens were cast. After the age of 28, 56 and 84 days, the bonding agent was applied and the new concrete was added thus make in it as full cylinder. Slant shear half specimens were cast. After the age of 28, 56 and 84 days, the bonding agent was applied and the new concrete was added thus make in it as full prism. Flexural half specimens were cast. After the age of 28, 56 and 84 days, the bonding agent was applied and the new concrete was added thus make in it as full prism. Analysis of the results indicates that bond strength at interface of old and new concrete is almost same in compressive strength
test. In split tensile strength test, bond strength at interface increased, when epoxy resin is used with comparison of as cast specimens. In slant shear strength test, bond strength at interface increased, when epoxy resin is used with comparison of as cast specimens. In flexural strength test, bond strength at interface increased, when epoxy resin is used. The application of an epoxy resin based bonding agent improve the bond strength.
