Research On Road Performance Of Tunnel Slag In Cement Stabilized Crushed Stone Base

In recent years,with the large-scale construction of highway projects in my country,it is inevitable that there will be a considerable number of tunnel projects excavated,and more and more tunnel spoil will be generated.At present,due to the limitation of technical conditions,the excavated tunnels have a low utilization rate of waste slag,and most of them are discarded,which will inevitably cause damage to the surrounding ecological environment.Therefore,the application of tunnel waste slag in cement stabilized crushed stone base as a research topic has very important practical significance.This article relies on the physical engineering of Huiqing section of Shan-Zhan Expressway in Guangdong Province.During the excavation of the tunnel,a large amount of granite spoil was generated.According to the characteristics of granite waste slag,the factory crushing process is selected for processing and corresponding control measures are taken during the production process to ensure the quality of the crushed aggregate.The specific research contents are as follows:First of all,the tunnel waste residue was screened,crushed value,water absorption,needle flake particle content and other tests.By analyzing the test data,it is determined that the basic characteristics of the waste slag meet the specifications.Secondly,the road performance of the cement-stable tunnel spoil is studied.Through the trial algorithm,the four different gradation ratios of the tunnel slag are determined,and then the compaction characteristic test is carried out on the four gradations under the condition of changing the cement content,and it is concluded that the four gradations are all in the cement content of 4.5The maximum dry density and the optimal water content are reached at %,and the optimal amount of cement is determined to be 4.5%;with different cement dosages,the four gradations are separately tested for 7d unconfined compressive strength.Two grades that meet the requirements of the specification were screened out for 14 d and 28 d mechanical performance and durability performance tests.Through the analysis of the test data,it can be seen that the grade 2 meets the requirements of the base layer when the 4.5% cement is mixed.Therefore,gradation 2 is selected as the target mix ratio of the mixture.Finally,considering the size of the cement dosage and the actual needs of the construction,make appropriate adjustments to the target mix ratio to determine the production mix ratio of the base mix.According to the characteristics of the project,the construction technology and construction method of the test section are formulated.At the optimal mineral ratio(20-25 mm gravel: 10-20 mm gravel: 5-10 mm gravel: 0-5mm stone chips = 24:33:9 :34)Underlay the base layer ofthe test section.Through the comprehensive analysis of the test results of the construction site test,the feasibility of the application of the tunnel slag in the cement stabilized gravel base has been fully proved.