| With the substantial application of "sponge city" material,the pervious coagulation shows excellent water seepage,wear-resisting,anti-skid,environmental protection,easy maintenance,sound absorption and noise reduction,etc.,and the paved road has become a "breathing" urban landscape road.The pervious coagulation material begins to be paid attention to and applied by people.Little belongs to the porous permeable concrete frame structure,fine aggregate,waterproof performance,therefore,but due to the complexity of permeable concrete internal pore structure and the stress concentration phenomenon caused by pore structure,its low strength and freeze resistance is poor operation,especially in temperature stress,frost heave effect and under external pressure load,the internal stress state and distribution is very complex.Therefore,under the conditions of test conditions and test time,it is of great significance to use computer simulation technology to explore the numerical simulation technology of pervious concrete and study its meso-mechanism under temperature load,frost heave and external pressure load.Reference and specification show that permeable concrete target generally between 10%～ 20% porosity can satisfy the basic intensity and permeable permeable concrete performance requirements,and under the room temperature curing cold(soaking curing curing under 0 ℃for 24 h after 24 h)after different porosity(10%,12%,14%,16%,18%,20%)under permeable concrete cube compressive strength tests have been carried out respectively,using ABAQUS permeable concrete finite element model is set up,The meso-stress state of pervious concrete under temperature load,frost heave and temperature-load coupling is studied respectively,and the stress-strain fitting curves of the test and temperature-load coupling model are compared.The main research contents are as follows:1)The basic physical properties of raw materials such as cement and crushed stone were tested to obtain the crushed stone crushing value,apparent density,tight packing density and other indexes,and the mix ratio of permeable concrete was designed in accordance with the Technical Specification for Permeable Cement Concrete Pavement.Of permeable concrete compressive strength test,permeable concrete cube compressive strength decreased percentage and the cumulative growth porosity relationship of a quadratic polynomial,itwas strength loss rate and porosity appear three times power function,the relationship between pore water freeze will increase in porosity cumulative loss rate rise at a rate of 4% to 6%when slow strength;2)With the help of finite element software ABAQUS,the python language recognition,write three dimensional random pore formation,and put in the algorithm,based on damage and combined with random pore mesoscopic permeable concrete geometric model,using the model the temperature boundary conditions,explores the different porosity(10%,12%,14%,16%,18%,20%)and different temperature(25 ℃,5 ℃ and 0 ℃,5 ℃,25 ℃)of permeable concrete internal stress influence.The results show that the internal stress of pervious concrete is more affected by porosity and less sensitive to temperature in a small range.3)On the basis of temperature load,frost heave was added to the model to simulate the pressure of pore water freezing and expansion.The results show that frost heave can slightly weaken the temperature shrinkage stress inside the pervious concrete caused by temperature decrease,but the stress change is still more sensitive to porosity on the whole.4)In pure pressure load,the cube compressive strength test and model size and almost the same change trend,also consider the temperature load,the frost heave effect and the external pressure load temperature-load coupling model is established,and model fitting the stress-strain curve and the cold of the test specimens stress-strain curve fitting size and almost the same change trend,and with the same formula fitting,fitting test and model parameters are within the scope of the error between,suggests that the author used the finite element model is consistent with the actual research. |
