Experimental Study Of Polyester Fiber Reinforced Cement Stabilized Gravel Base Crack Resistance

Semi-rigidity base has been the most common type of the grassroots used inhighway and urban road construction in China,and cement stabilized base is widelyused for its features such as high strength and good integrity etc.As one of the mostpopular type of semi-rigidity base in the west,cement stabilized gravel will inevitablyresult crack and deformation,for its inherent properties such as dry shrinkage andswelling,low temperature shrinkage and poor resistance to bending deformation.Oncegenerated at the grassroots,the micro-cracks will extend upward and make the asphaltpavement produce reflection cracks under the influence of environment andload.Reflection cracking is also one the major diseases which endanger the safety ofthe road of China’s western region.Firstly,the paper explores the formation mechanism of the semi-rigid base asphaltpavement cracks,and sums up the common measures currently used in preventingasphalt pavement crack.In view of the cement stabilized gravel base commonly usedin Xinjiang region,this paper puts forward that mixing polyester fiber can improve itscrack resistance.In line with specification requirements,we designs the gradation ofthe skeleton dense of the mixture,and conducts electric compaction test for the cementstabilized gravel in accordance with the C method,and finally obtains the maximumdry density and optimum moisture content.Specimens are used isostatic pressingcompaction method to ensure its degree of compaction and cured specified age understandard conditions.And then through the unconfined compressive strength test,tensile test,tensile modulus test and shrinkage test,it studies the impact of thepolyester fiber on strength and resistance to deformation of cement stabilized gravel.Finally,this paper discusses the existing evaluation methods of crack resistance ofsemi-rigid base,and summarizes the differences between them.Through themulti-index evaluation of fiber cement stabilized gravel,it finds out the optimum combination of fiber length and content.Tests proved that the polyester fiber plays asufficient role in strengthening,toughening and crack resistance in the cementstabilized gravel,and polyester fiber cement stabilized gravel has better crackresistance.