EXPERIMENTAL RESEARCH ON MECHANICAL PROPERTIES OF COMPOSITE CONCRETE SLABS WITH DIFFERENT JOINT CONSTRUCTION MEASURES

In order to simplify the joint construction measures of the two-way truss reinforced concrete composite slab and improve the mechanical properties of the joint, three kinds of reinforced close joint were proposed:strengthened additional reinforcement joint, integral groove joint and interval groove joint. The static loading tests were conducted on three closely jointed composite slabs with different joint construction measures and one composite slab with post-cast strip. The failure modes, crack distribution, stiffness, ultimate bearing capacity and stress development of the joint reinforcement of each composite slab were compared and analyzed. The results showed that strengthening the joint reinforcement could improve the bearing capacity of the composite slabs with close joint; the integral groove and interval groove at the joint could not only control the centralized development of the mid-span cracks of the composite slabs with close joint, improve the crack distribution, but also effectively improve the bearing capacity and stiffness of the composite slabs, and its bearing capacity could reach more than 90% of the post-cast strip composite slabs. Based on the experimental results, the design suggestions and construction requirements of three kinds of strengthened close joint were put forward.