The Experimental Study Of Cast-in-situ Concrete Composite Beam With Permanent Formwork

To reduce the construction cost, shorten the construction period, to reduce laborintensity and to save energy and protect environment needs, a fiber reinforcedpermanent formwork made of glass fiber, steel-wire mesh, cement-based materials isproposed in this paper during reinforced concrete construction. During theconstruction, the permanent formwork and concrete will be pouring into one to makecomposite structure. Thus permanent formwork will be part of the whole structurecomponent, and will bear the load with concrete together.Three parts are included in this paper. They are Experimental study of permanentformwork cement-based composites, permanent formwork and in-situ concretecomposite mechanical properties of composite beam research, and finite elementsimulation. The permanent formwork cement-based composites have been studied. Inorder to obtain the best performance of cement-based composite materials, differentmixture ratio of cement-based composites is studied in this paper. Through theresearches, bending test, compression test and splitting tensile test, ideal mixtureratio of cement-based composites is obtained: water-binder ratio:0.33; fiber contentfor quantity:3%; latex content in cement content:3%; cement-sand ratio:0.3and flyash content of cement content:3%.The mechanical behavior of permanent formwork and cast-in-place concretecomposite beams has been studied. Though the contrast test between none-drillingprocessing of composite beam and ordinary concrete specimens in the same condition,two conclusions are obtained: one is that in order to ensure the bonding properties ofconcrete and formwork, permanent formwork must pass through the drillingprocessing; the other one is that it is not conducive to the normal work of concretebeam without any processing of permanent formworks for the production of laminatedbeams of concrete stripping. Though the contrast test between permanent formworkand concrete composite beam with different drilling processing, three conclusions areobtained. The first is that when the drilling depth is smaller, aperture larger, it is more advantageous for bond behavior between permanent formwork and concrete and itnearly reached the80%-90%bearing capacity of the concrete beam.The second is that cracking load of composite beam which is higher thanordinary concrete. The third is that the deformability of composite beam with bettercohesiveness properties is higher than ordinary concrete.Basing on the test results, and considering the bond-slip between permanentformwork and concrete, mechanical behavior, deformation and craze status ofcomposite beam in different processing mode are analyzed by finite element softwareANSYS. Simulation and experimental results are basically consistent.