Experimental Research On Shear Properties Of RPC-NC Composite Structure Bonding Surface

ABSTRACT:Reactive Powder Concrete(RPC) is a kind of new composite material with good mechanical property and high durability which can adapt well to the development requirements of long-span, high-rise, heavy-load and severe using environment modern engineering. In the light of the high production cost, we raise the idea of composite structure of RPC and normal concrete(NC). And whether the two kinds of material could work together effectively is the key point for its widely application in engineering. The shear properties of the bonding surface of RPC and NC plays an important role in the integrated performance of the composite structure. So we determine to investigate the shear properties of the bonding surface of the composite structure in this paper. To address this situation, the paper carried the following research and get relevant conclusions:(1)A push-out test of nine specimens without lateral pressure and twenty seven specimens with lateral pressure is carried out. Full notes about the process information, data acquisition, key reaction parameters are made. Then we analyze the failure mechanism of the double bonding surfaces of RPC-NC composite specimens and get the shear stress-displacement curves of these test specimens. These experimental data show that the lateral pressure has a great impact on the tests results, the first break point of the specimens with lateral pressure are far above those without lateral pressure. And there are rising steps in the shear stress-displacement curves of these specimens with lateral pressure, which is very different with those without lateral pressure.(2) After comparison and analysis of the experimental phenomenon and results, we find that the shear capacity of these specimens without lateral pressure increase with the increasing of the strength grade of concrete, especially the tension strength has a great effect on the shear capacity.(3)We find that the lateral pressure has a significant influence on the shear capacity of the bonding surface between RPC and NC, the shear capacity could substantial increase with the increasing of lateral pressure, but the rate of increase decreases with the increasing of lateral pressure. So we conjecture that there is an threshold value, after which the shear capacity could not increase with the increasing of the lateral pressure, and this threshold value should be determined by the experimental researches in the future.(4)A finite element analysis on the shear capacity of bonding surfaces in the RPC-NC specimens is carried out by ABAQUS software. We find that most of the simulation results agree well with the experimental results, but some simulation results represent a deviation to the experimental results. There are many factors could lead to the deviation, for example the bad stability of concrete strength, eccentric loading process, the limitation of the test conditions, and so on.