Experimental Study On Fracture Property Of Nano High Performance Concrete

As one kind of High Performance Concrete (HPC), with the advancement of research and the reduction of manufacturing cost of Nano materials, Nano High Performance Concrete (NHPC) has showed its wide application potential on structural engineering in future. However, the research on bend ductility and fracture performance of NHPC, especially of Steel Fiber Reinforced NHPC (SFRNHPC), is too few to demands of construction. This paper showed the effect of fundamental mechanical performance, bend ductility and fracture performance influenced by the mixing proportion of Nano SiO2and steel fiber based on large amount of tests. The main contents including in this paper are as following:(1) The preparation theory of NHPC was analyzed, and the mix proportion of NHPC was determined applying the overall calculation method. The influencing rule of Nano SiO2and steel fiber on the performance of NHPC was obtained through the test of slump and slump spread.(2) With3d,7d,28d,60d as the curing period, the rules of the effects of Nano SiO2and steel fiber on the strength of HPC is obtained through the test of cubic compression strength.(3) With28d as the curing period of concrete specimens, the rules that Nano SiO2and steel fiber influencing on the axial compressive strength and elastic modulus of HPC were obtained through the axis compressive strength test and compressive elastic modulus test.(4) With28d as the curing period of concrete specimens, the flexural strength and flexural modulus are studied, and the rules of effects of the Nano SiO2and steel fiber influencing on flexural strength and flexural modulus of NHRC were obtained by three-point loading experiment.(5) Based on experiments of three-point bending beam test, with28d as the curing period of concrete specimens whose size are100mm×100mm×400mm, the rules of the bend ductility influenced by the dosage of steel fiber were analyzed applying the method of ASTM C1018Toughness Index and DBV which is Germany fiber reinforced concrete standard.(6) Through the three-point bending beam test, with a set of specimens whose size are100mm×100mm×515mm aged28d, the bend ductility was studied in this paper. Taking the effective crack length, instability fracture toughness, the crack fracture toughness, fracture energy, critical crack opening displacement and limit fracture opening displacement as evaluation indices, the basic influence rules of Nano SiO2and steel fiber on the fracture property of NHPC were obtained, and the notch sensitivity of the fracture specimens of NHPC was also studied.