Study On Durability And Mechanical Properties Growth Law Of Coal Gangue Pavement Base Mixture

The two wastes of coal gangue and steel slag are produced in large quantities every year.The large amount of concentrated stacking not only occupies land,but also poses a serious threat to the surrounding environment.There have been studies on the application of coal gangue mixture made of coal gangue,steel slag and lime according to a certain ratio to the pavement base,but only the mechanical properties of the mixture have been studied,but the growth law of its mechanical properties has not been studied.The road is exposed to the outdoors,will be washed by rain,and the northern winter is extremely cold,highway frost damage occurs from time to time,every year because of the traffic problems caused by highway frost damage is not uncommon,at the same time,steel slag and lime will encounter expansion problems in the process of use,in order to prevent the cracking of the road surface in the process of use.Therefore,this dissertation will study the following contents.In this dissertation,the physical and chemical properties of coal gangue,steel slag and lime are determined by experiments to ensure that their indicators meet the requirements of the specification.According to the uniform design method,the mix ratio scheme of the durability test of coal gangue steel slag mixture was formulated,and the specimens were made and cured according to the specification.According to the specification,the freeze-thaw cycle test of coal gangue steel slag mixture was carried out,and the results were analyzed by regression analysis to study the influence of various factors on its frost resistance.The findings demonstrate a correlation between the mixture’s frost resistance and the amount of steel slag and lime.The compressive strength and BDR value after freeze-thaw exhibit a tendency of initially increasing and then decreasing with an increase in lime concentration.The compressive strength after freezethaw has a tendency of initially increasing and then reducing with an increase in steel slag concentration,but it has no impact on the BDR value.In order to study whether the water stability of the mixture can meet the requirements of pavement use,the dry-wet cycle test scheme is designed,and the influence of various factors on the water stability is studied after the number of cycles and the test method.After 15 times of dry-wet cycle,the strength does not decrease but increases.The compressive strength after dry-wet cycle is related to the content of lime and steel slag.The compressive strength reaches its maximum point,gradually declines as the amount of lime grows,and gradually rises as the amount of steel slag increases.The effects of lime and steel slag on the mixture’s expansion were researched.The findings demonstrated that the expansion rates of steel slag and mixture both increased over time,with the steel slag expanding practically linearly while the combination expanded rapidly at first before stabilizing.The grade of the lime and whether it has been sieved affect how much it expands.After determining the proper mixture ratio,the growth law was investigated and tests were conducted on the mixture’s unconfined compressive strength,rebound modulus,and splitting strength at various ages.Three mechanical properties of mixture increase with the increase of age,the early growth is faster,the later growth is slower,three mechanical properties of 180 d is close to the ultimate strength.