Bond behavior of corroded reinforcement in concrete wrapped with carbon fiber reinforced polymer (CFRP) under cyclic loading is experimentally investigated. An electrolyte corrosion technique is used to accelerate the corrosion of the steel bar in cylindrical concrete specimens. Wrapped specimens are strengthened with one layer of CFRP after the reinforcements are corroded. The experimental parameters investigated include: corrosion level, CFRP wrapped and number of loading cycles. Test results indicate that bond strength and area of hysteretic curve of CFRP wrapped specimens are larger than those of the unwrapped specimens. With increasing the number of loading cycles, the bond strength and area of hysteretic curve decrease gradually, especially at the 1st cyclic loading. The CFRP wrapping reduces the bond degradation rate effectively and prevents the bond-splitting failure of the corroded concrete specimens.
As the construction of high-rise building to expand the product line of lightweight concrete. becomes popular, improvement and innovation are required In this paper, two ways of fabricating lightweight concrete were combined to make a new kind of super lightweight concrete. Normal aggregate is replaced with expanded polystyrene （EPS） granule, while foam is introduced to facilitate fabrication process. As a result, super lightweight concrete denoted as EPS foamed concrete is fabricated, whose bulk density is less than 500 kg/m3. Compressive properties of EPS foamed concrete with bulk density 300--500 kg/m3 were investigated by stress-strain curve. It＇s demonstrated that the compressive strength ranges from 0.7 to 2.5 MPa, which is higher than that of similar products. Furthermore, low elastic module and high residual to ultimate strength ratio ensure its excellent deformation and energy absorption capacity. At last, numerical analysis was performed to interpret the inherent variation of elastic modulus and failure mechanism of this material. The results show that EPS foamed concrete is a kind of super lightweight, easy to fabricate material with excellent compressive property and profound utilization potential.
