Study Of The Fiber Concrete With High Durability And Crack Resistance Suitable

In order to develop new pavement materials with high durability and crack resistance suitable for China's civil aviation airports,we will research new technologies that use high-toughness materials in airport pavement engineering to achieve the high durability and structural rationalization.Significantly,by improving the crack resistance and toughness of pavement concrete,the aim of this paper is to enhance the operation safety of the airport pavement and save a large cost of maintenance and reconstructions for our country.This paper focuses on the fiber concrete mix proportion that meets the technical requirements of airport concrete pavement maintenance,and studies basic mechanical properties of concrete with different PVA fiber content,including the application,bending strength,compressive strength,impact resistance,splitting tensile strength and other properties of fiber concrete.It provides experimental data reference for the future use of PVA fiber for road pavement,airport runways and bridge panels.The main results of this paper are as follows:Both PVA fiber and steel fiber can be uniformly dispersed in the concrete.The fiber reinforced concrete has good workability and work ing performance.The cracking resistance effect of PVA fiber in crack initiation and microcracking stages of concrete is obvious,and it can effectively prevent the further expansion of cracks.Compared with plain concrete,the fracture toughness and impact resistance of fiber concrete are significantly improved.In the construction and repairment of airport pavement,the mix proportion of PVA fiber has little effect on the compressive strength of concrete,but it has effect on the improvement of the bending strength and sp litting tensile strength.And with the increase of the PVA fiber volume fraction,the splitting tensile strength of the fiber concrete has a tendency to increase more slowly than that of the plain concrete.The bending strength of PVA fiber reinforced concrete for repairment measured at 6 hours is not less than 5.0 MPa,which meets the design requirements of cement concrete for airport pavement in the "Specifications for Cement Concrete Pavement Design of Civil Airports"(MH/T5004-2010).The test sand-binder ratio of ultra-high-performance concrete for airport pavement repairmen is 1.4:1,1.3:1 and 1.1:1.Analysis of the test data shows that the decrease of sand-binder ratio leads to an increase of colloid materials,the tighter packing of aggregates by collo ids,and the improvement of the bending strength of the smaller mastic samples.This paper studies sand thickness ratio.The ratio of samples is 4:6,5:5 and 6:4,and their bending strength in turn increases.The larger the proportion of fine sand is,the more the bending strength increases.If the amount of silica fume,cement,and flyash changes from each other and the total amount of colloids is relatively constant,the change of strength between these concrete is not obvious.The water cement ratio decreases from 0.19 to 0.18,which can effectively improve the compressive strength and bending strength of samples.The increase of steel fiber content has little effect on the increase of the bending strength of samples.