Grooving Effect On Flexural Behaviors Of T-section Concrete Beams Reinforced With Near-Surface Mounted FRP

In this paper, three reinforcement parameters of groove depth, groove position, the binding material are studied on condition of the pre-splitting or not through 7 T-section beams reinforced with NSM-CFRP rods. The development of the crack, deflection, strain of concrete, steel bar and CRFR rod, failure load and the failure mode of the reinforced beams can be obtained. Based on the research achievements of FRP reinforcing concrete beams of domestic and foreign scholar, this paper analyzes the beam’s failure mode and deduces the calculation method of flexural capacity on condition of debonding failure mode.The results show that, with the value of K increased, the beam’s failure mode is from the debonding of concrete-adhesive layer at flexural section -to the debonding only at the loading point. The range of debonding becomes smaller but the degree of the debonding increases; With the value of a’e increases, also known as the groove position being far away the edge of the plate’s bottom, the failure mode of the concrete beams is from the debonding of the edge of the concrete beams’bottom to the debonding of all the concrete beams’bottom at the loading point. The degree of the debonding and the ultimate bearing capacity of the reinforced beams increases. The results also show that, on the condition of K>2 and presplitting, the pasting material of epoxy mortal can’t control the development of reinforced beams’crack availably; On the condition of K>2 and non-presplitting, the pasting material of epoxy mortal and epoxy rein can all control the development of reinforced beams’crack effectively. Because of the characteristic of the low cost and the simple and convenient construction, the pasting material of epoxy mortal can be popularized in the reinforcement project in compare with the epoxy rein, whereas the reinforced concrete beams pasted it has a more enhancement of ultimate bearing capacity.Based on the analysis and summary of the failure mechanism, according to the local bond-slip curves "the concrete tooth model" advanced by De Lorenzis and Mohr’s theory failure, this paper deduces the calculation method of T-section beam’s flexural capacity reinforced with NSM-CFRP rods on the condition of debonding failure mode. The calculation results have good agreement with the test results.