Experimental And Simulation Studies On Structure Performances Of SHCC Precast Slabs

Strain hardening cement-based composites(SHCC)made by polyvinyl-alcohol(PVA)fiber reinforced cement mortar possesses high ultimate tensile strain of more than 3%.The failure mode of SHCC is ductile failure,instead of fragile failure.The applications of SHCC into civil engineering structures are helpful to improve the bearing capacity and durability of structures,and reduce their weight.Then,the structural performances of precast hollow slab structure have been studied by comparison with ordinary cement mortar precast slab.The analytical model and FEM model have been set up to calculate the bearing capacity of SHCC precast slab.The main conclusions is drawn up as follows:(1)With the addition of metakaolin(MK)the mechanical properties of SHCC have been improved obviously.That is,the first crack strength,ultimate tensile strength and ultimate tensile strain of SHCC containing MK was 41.9 percent,24.8 percent and 15.92 percent higher than that of SHCC without MK,respectively.The optimum content of MK in SHCC was 10%.(2)Compared SHCC precast slab with ordinary cement mortar precast slab specimens under the four point bending test,the failure process,crack distribution,deflection and strain were analyzed.PVA fibers in SHCC had played important roles to improve the strength and prevent cracking ability.Multiple fine cracks could be observed on the bottom of SHCC prefabricated plate.And its failure load was two times more than that of the ordinary prefabricated cement mortar slab.(3)The equivalent section of SHCC precast slab was simplified.Then,according to relationship of stress and strain and basic assumptions,the mechanical model was established to calculate the first cracking load,yield load and ultimate load of SHCC precast slab.Compared with the test results,the accuracy of the theoretical analysis was verified.Further,FEM model of SHCC prefabricated plate has been set up by using ABAQUS.The FEM results were consistent with the experimental results.