Study On Design Method And Performance Of Grouting Semi-flexible Pavement Materials

Semi-flexible pavement is a kind of pavement structure formed by pouring cement mortar into the large void basic asphalt mixture.This pavement structure is characterized by both the "flexibility" of asphalt pavement and the "rigidity" of cement concrete pavement.The infusion of cement mortar caused the original "skeleton-void" structure of the open-graded asphalt mixture to become a "skeleton-compact" structure,which greatly changed the pavement performance.Based on the current research at home and abroad,through a large number of experiments and theoretical analysis,this paper has studied the design method,molding parameters and pavement performance of semi-flexible mixtures as comprehensively as possible.Using orthogonal design method,the influence of various factors on the base asphalt mixture was studied.The evaluation indexes are air void,marshall stability,drainage test and water cantabro test,and the optimal mix ratio of the base asphalt mixture is obtained.Cement mortar is a key factor affecting the performance of semi-flexible composite pavement.It’s grouting parameters and mortar proportioning have an important impact on the pavement performance of semi-flexible pavement.This article uses the orthogonal design method to study the proportioning of cement mortar.The evaluation indicators are flow property,flexural strength(3d)and compressive strength(3d).Finally,the optimal mix proportions of P.O42.5R and Densit cement mortars were obtained.After repeated tests,a method for forming semi-flexible test pieces was proposed,focusing on the cement mortar pouring method.The air void and mortar filling rate of the semi-flexible test pieces after molding were calculated,which proved that the method of forming semi-flexible test pieces in this paper is feasible.The research focus of this paper is the pavement performance of semi-flexible composite pavement.After a large number of tests,it can be seen that the semi-flexible mixture is superior to ordinary asphalt mixtures in terms of high temperature performance,water stability and fatigue performance,and the low temperature crack resistance is slightly reduced,but it can meet the requirements for road performance.The type of cement mortar has a great impact on the pavement performance of semi-flexible mixtures.The two types of cement mortar semi-flexible mixtures studied in this paper have their own advantages and disadvantages in terms of performance.The Densit type has better water stability and low temperature crack resistance than the P.O42.5R type.In terms of high temperature performance and fatigue resistance,the P.O42.5R type shows advantages.