| Porous concrete as pavement material requirements that should have sufficient strength,and good permeability,but its porous nature determines both the contradiction between the above two characteristics,in the actual engineering often poor bearing capacity,small cohesive force between coarse aggregate and freezing-thawing resisting performance is low,easy cracking and difficult to repair and cavity block.For these reason,some scholar had to study for this by adding steel fiber or soft polypropylene fiber to enhance the permeable concrete substrate performance,but not solve in practice because of the durability of steel fiber corrosion caused by falling,and the disadvantages of flexible fiber decreased permeability of porous concrete.Rigid polypropylene fiber has the characteristics of steel fiber with high elastic modulus and compressive strength of concrete can be improved,but it will not rust,have flexible polypropylene fiber at the same time the advantages of light weight,high strength,low price.Now in our country the study of porous concrete is mainly materials and the research of mechanical properties of porous concrete as pavement test research.Test of modified polypropylene fiber Permeable concrete used for surface rigidity,load model of road test.As concrete for road surface should have enough strength and durability,therefore,in the model road tests are carried out at the same time,make rigid durable performance of modified polypropylene fiber Permeable concrete materials research.In this paper,the main content is:(1)Selection of rigid polypropylene fiber volume content,respectively,0%,0.3%,0.6%,1% modified porous concrete specimen,complete the freeze-thaw cycle test.The volume content of 0% Permeable concrete freezing and thawing cycles for 50 times,the corresponding quality loss rate of 4.64%.The volume content of 0.3% specimen maximum cycle times for 75 times,the corresponding quality loss rate was 5.73%.The volume content of 0.6% specimen biggest freeze-thaw cycles for 100 times,the corresponding quality loss rate was 7.56%.The volume content of 1% specimen biggest freeze-thaw cycles for 125 times,the corresponding mass loss value of 8.64%.Mixed with rigid polypropylene fiber improves the permeable concrete antifreeze performance effectively.(2)Projects prophase research to determine the volume content of 1% of modified polypropylene fiber modified porous concrete has the best mechanical properties.In this paper,the rigid Permeable concrete of polypropylene fiber volume content of 1% compared with the normal Permeable concrete resistance to sulfate dry-wet circulation test.After 60 sulfate dry-wet circulation,rigid modified polypropylene fiber Permeable concrete corrosion resistant coefficient of 60.5%,normal permeable concrete corrosion resistant coefficient is 58.05%.Rigid polypropylene fiber added to improve the permeable concrete resistance to sulfate of dry-wet cycle performance.(3)This article will rigid polypropylene fiber volume content of 1% Permeable concrete with normal permeable concrete early shrinkage test.After 45 d,rigid polypropylene fiber Permeable concrete shrinkage value is 5.41×10-4 mm,ordinary Permeable concrete shrinkage value is 3.91×10-4 mm.The mixed rigid polypropylene fiber can effectively reduce the permeable concrete shrinkage during hydration reaction,decrease the cracking of the internal.(4)This article will rigid polypropylene fiber volume content of 1% Permeable concrete with ordinary permeable concrete material shear performance experiment was carried out.The shear strength of fiber Permeable concrete C value size is 2.022 MPa,internal friction Angle is 15.85 °.Average shear strength of the permeable concrete C value size is 1.855 MPa,internal friction Angle is 14.95 °.Rigid polypropylene fiber mixed with effective to enhance the shear properties of Permeable concrete material.(5)The best ratio of fiber stiffness polypropylene fiber Permeable concrete as the surface material,dry state to simulate the sections and the heavy rainfall saturated state model of overall bearing capacity and deflection value performance test,etc.Rigid polypropylene fiber model sections under the dry soil base state of maximum bearing capacity and deflection value is 98 kn and 8.97 mm respectively,when loading damage does not appear obvious crack model section,the overall performance is good.Ordinary model maximum bearing capacity and deflection deformation value of the section 66 kn and 5.99 mm respectively,load destroyed roads throughout midpoint appeared at the edge of the short type fracture.Rigid polypropylene fiber sections in moist soil under the base state of maximum bearing capacity and deformation value respectively is 86 kn and 11.67 mm,destroyed model does not appear obvious cracks,the overall performance is good.Maximum bearing capacity and deflection deformation of the normal section 53 kn and 5.62 mm,when loading damage cracks in the midpoint appeared at the edge of the short route,and has the obvious warp phenomenon.In the same state of soil under loading,fiber model road sections have stronger than that of ordinary model sank bearing capacity and flexural deformation ability.Rigid polypropylene fiber sections have stronger board performance.(6)In a simulated road buried in the soil base soil pressure gauge,is obtained by earth pressure meter readings change the earth pressure curve of load and its stress diffusion path.Dry soil base state under load,the load value is 65 kN,rigid polypropylene fiber model section of equivalent round earth pressure just below 2 meter readings of 5.591 kN,ordinary model 2 readings section of earth pressure is 5.51 kN.Heavy rainfall saturated state,the load of 52 kN,rigid polypropylene fiber earth pressure model section 2 readings of 5.54 kN,number 2 in normal section of earth pressure is 5.51 kN.No matter dry or heavy rainfall saturated soil base condition,fiber road surface than ordinary roads have stronger ability of load diffusion. |
