Study On Composition And Pavement Performance Of Cement Stabilized Base Material For Coal Gasification Coarse Slag

In order to meet the increasing demand stimulated by heavy traffic and vehicle loads,semi-rigid base pavement has become one of the main structures of road engineering.The solid waste--coal gasification slag,which is usually accumulated or buried.However,long-term storage will not only take up a lot of land resources,but also cause land and water pollution under the rain erosion.Part of very fine particles in cinder will even cause the sand storm under the action of wind.In order to make proper use of coal gasification slag,the thesis studies feasibility of the application of coal gasification slag in the semi rigid base with suspended dense structure and skeleton dense structure and the road performance is also discussed.At first,the technical characteristics of coarse coal gasification slag and fine slag are comparative analysed through experiment,including the residual carbon content,density,particle size distribution and morphology.The microstructure of the slag is studied by SEM.EDS and XRD is used to analysed its mineral composition.Secondly,the influence of coal gasification slag on the strength of cement based material is investigated by the strength test of coal gasification slag mortar.The hardening product of coal gasification slag and inorganic cementitious material is analyzed by SEM,EDS and XRD.The results show that,the fine coal gasification slag is not suitable for semi rigid base materials but the coarse coal gasification slag can be used.According to the above conclusions,9 kinds of suspended dense structure and 9 kinds of skeleton dense structure coal gasification coarse coal content in semi-rigid is put forward,and the coarse aggregate void volume and binder volume compaction is tested to examine the quality of framework dense structure.Optimum water content,maximum dry density and the consumption of optimum gasification coarse slag and lime dosage in each mixture are determined through 7 days of compaction test and unconfined compressive strength test.Finally,6 kinds of suspended dense and 6 kinds of skeleton dense mixture are designed to determine the optimum cement content.And determine the suspended dense and skeleton dense structure of cement,lime and coarse coal gasification slag are determined,respectively 4%,3% and 25%,20%.On the basis of the above analysis,2 groups of the optimal suspension dense structure and 2 groups of the optimal skeleton dense structure mix proportion of semi-rigid base material are determined.Finally,the splitting strength and dry shrinkage performance of the semi rigid base material with suspended dense structure and framework dense structure are studied.The factors that affect the performance of these two kinds of pavement are put forward and the reference is provided for the application of coal gasification coarse slag in semi-rigid base course material.