| The waste brick slag is produced by the broken bricks after the demolition of the old buildings.There are some microcracks on the surface,and the strength of the waste brick slag is relatively lower than that of the ordinary brick slag.However,its proportion in construction waste can not be underestimated,about 30% ～ 50%.How to utilize the waste brick slag has become a research hotspot in recent years.In the existing research,the high feasibility is to use it as aggregate in road engineering,but it is only limited to some basic indoor tests,and the actual use cases are few,which restricts the process of putting it into use in large quantities.Due to the influence of vehicle load and atmospheric environment in the actual use process of pavement structure,compared with ordinary base course,some early diseases may occur,or diseases may occur frequently in some weak parts,resulting in a substantial increase in maintenance costs.Therefore,it is necessary to have an overall understanding of some basic mechanical properties of semi-rigid base with waste brick slag,and to analyze its dynamic response under the action of vehicle moving load and atmospheric temperature.After reading a large number of documents and specifications,the basic physical properties of waste brick slag are understood through some basic physical tests,and then a certain proportion of waste brick slag is used to replace the natural aggregate in the semi-rigid base,and the basic mechanical properties of cement stabilized waste brick slag are studied,The finite element software ABAQUS and visual studio are used to model and analyze the dynamic response of semi-rigid base of waste brick slag under the single and coupling action of moving load field and temperature field.(1)The basic physical properties of waste brick slag(including crushing value,apparent density,bulk density,water absorption,needle flake particle content,etc.)were tested and studied.It was found that the basic physical properties of waste brick slag decreased in different degrees compared with natural aggregate,but basically met the use requirements of base aggregate;(2)5% and 6% cement were used to stabilize the aggregates with different replacement ratio of waste brick slag,and the mechanical properties such as 7d unconfined compressive strength and elastic modulus were tested.The results showed that the mechanical properties decreased with the gradual increase of replacement ratio of waste brick slag.(3)The pavement structure is designed,and the dynamic response of semi-rigid base with waste brick slag is compared with that of ordinary semi-rigid base under the action of vehicle moving load.The modeling analysis shows that except for the improvement of longitudinal tensile stress,other dynamic response evaluation indexes of each layer show different degrees of deterioration,After modeling and analyzing by increasing the thickness of the base,it is found that it can make up for the dynamic response index;(4)ABAQUS and visual studio are used for modeling and analysis to study the change of temperature stress of pavement structure under the single action of temperature field and the dynamic response of pavement base under the coupling action of vehicle load and atmospheric temperature.The results show that with the gradual increase of replacement ratio of brick and slag,the dynamic response of pavement base under the coupling action of vehicle load and atmospheric temperature is analyzed by finite element method,In the pavement structure,the probability of disease at the junction of surface course and base course increases gradually,mainly because when the replacement ratio of waste brick slag increases gradually,the allowable tensile stress of base course decreases gradually,while the longitudinal and transverse shear strains at the junction of surface course and base course increase gradually.It can be improved by appropriately increasing the thickness of surface course and adding bonding layer at the junction of surface course and base course. |
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