Study On Application Of Tuff Cave Slag In Skeleton Dense Cement Stabilized Macadam Base

The construction of the tunnel can quickly improve the efficiency of transportation.With the improvement of China's comprehensive national strength,a large number of tunnels have emerged on the expressways in various regions,but the slag generated by tunnel excavation has also grown rapidly and cannot be utilized.The slag not only pollutes the environment but also occupies land resources.This paper mainly conducts a large number of experimental studies on the feasibility of applying tuff slag excavated in the Lianhua Expressway Lianhuashan Tunnel to the cement stabilized macadam base.The main work and conclusions are as follows:Through the analysis and research on the crushing process and quality control of the excavated tuff slag,it is considered that the combination of the crushing equipment of the"crush crusher+impact crusher" mode and the use of the three-stage crushing can obtain the expected aggregate effect.After tasting the samples of different samples,the samples were chemically tested by X-ray diffractometer.The chemical composition consisted of Si02,A1203 and Fe203.However,the content of each sample was close,and it was difficult to judge the quality of the samples by chemical composition.The relative bulk density of the samples of different tuff caverns is between 2.690 and 2.706,and the saturated compressive strength is between 30 and 70 MPa.The crushing value of the crushed aggregate can meet the aggregate requirements of the cement stabilized macadam mixture.Through literature analysis,the design of dense skeletal cement stabilized macadam mixture is designed to meet the design strength of 3.5?5.OMPa.The cement dosage is 4.0%,and the optimum moisture content is 5.1%.The mechanical properties of cement stabilized tuff slag mixture were studied.The strength and strength growth rate of four kinds of tuff slag samples were compared.The correlation between important technical indexes of sample mother rock and aggregate and mechanical property test results was analyzed.The correlation between the compressive strength,water absorption,crushing value and strength of the parent rock is the best,and there is no significant correlation with the rock density.The effects of vibration and static pressure on the mechanical properties of the cement tuff are shown in the room.The results show that the strength of the cement stabilized tuff slag mixture is significantly better than that of the hydrostatic forming.The cement stabilized macadam base layer is prone to dry shrinkage.In this paper,the water loss rate,dry shrinkage,dry shrinkage strain and dry shrinkage coefficient of the cement stabilized tuff cavity slag mixture are tested.The test results show that the water loss with age increases.The rate gradually decreased.The accumulated water loss rate and accumulated dry shrinkage in the first 7 days accounted for 65.69%and 54.71%of the previous month,indicating that the health care link of the cement stabilized macadam mixture should be paid attention to during the construction.By regression of the cumulative water loss rate and the cumulative dry shrinkage strain and the cumulative dry shrinkage data,the former and the latter both have an exponential growth relationship.Finally,the test section was paved with cement stabilized tuff slag mixture,and the construction process and quality control points were summarized.The quality inspection results show that the cement stabilized tuff slag mixture can be used as the pavement base layer with good performance.