Mix Ratio Design And Performance Test Research Of Single Particle Size Pervious Concrete

With the acceleration of China's urbanization construction process,various types of infrastructure construction have been gradually improved.Although the hardened road surface has greatly improved people's travel conditions and brought convenience to life,it has also triggered a series of environmental problems.In order to solve the environmental problems brought about by urbanization,the construction concept of “Sponge City” came into being.As the main material of water-permeable paving,permeable concrete has good water permeability and permeability,and it has quickly become a research hotspot.Pervious concrete is a skeleton-void structure formed by the cement slurry wrapped on the surface of the aggregate.Therefore,the thickness of the cement slurry has a crucial influence on the performance of the pervious concrete.In order to clarify the influence of cement slurry thickness on the performance of permeable concrete,this paper first sets the water-cement ratio of 0.25,0.27,0.3,0.32,and the thickness of the slurry is 0.2mm,0.4mm,0.6mm,0.8mm.The effects of water-cement ratio and slurry thickness on the performance of permeable concrete were analyzed.Based on this,a mix design of permeable concrete based on slurry thickness was proposed.Finally,by adding appropriate amount of fly ash and gathering Acrylic fiber to improve the performance of permeable concrete.The main findings of this paper are as follows:(1)The optimum water-cement ratio of permeable concrete ranges from 0.27 to 0.3.The strength increases with the increase of water-cement ratio and then decreases.The porosity decreases with the increase of water-cement ratio.(2)The strength of the permeable concrete increases with the increase of the thickness of the slurry,and the porosity decreases with the increase of the thickness of the slurry.The range of the slurry corresponding to different strengths and porosity is as follows: when the strength is 10-20 MPa,the thickness of the slurry is 0.34?0.52mm;the strength is 20?30MPa,the thickness of the slurry is 0.48?0.67mm;30?40MPa,the slurry The body thickness is0.65mm?0.8 mm.The porosity is 10%?15%,the thickness of the slurry is 0.53?0.71mm;the porosity is 15%?20%,and the thickness of the slurry is 0.42?0.53 mm.(3)Based on the thickness range of the slurry,a design method of the permeable concrete mix ratio based on the thickness of the slurry is proposed to make up for the shortcomings of the common mix design method in the specification.(4)Appropriate amount of fly ash and polypropylene fiber can improve the strength of permeable concrete.Fly ash can slightly increase the porosity of permeable concrete.Polypropylene fiber has little effect on porosity.The optimum amount of fly ash is 10%,and the optimum volume of propylene fiber is 0.1%.