Experimental Study On Crack Resistance Of Basalt Fiber Geogrid Reinforced Cement Stabilized Macadam

Cement stabilized macadam has been widely used in the construction of high grade highway because of its good durability and stability,but it is also susceptible to susceptible to the influence of temperature and humidity to form cracks,which leads to the decrease of the overall strength and durability of asphalt pavement.To solve this problem,basalt fiber geogrids are laid in the middle of cement-stabilized macadam base to improve the crack resistance of semi-rigid base.Through a large number of laboratory tests,the following research conclusions are obtained:(1)The interfacial interaction between cement-stabilized macadam and basalt fiber geogrids was studied by pull-out test.A pull-out instrument for this test was designed and found through the pull-out test:Under different overlying compression loads,the peak value of the drawing displacement and drawing force will also change,that is,the peak value of the drawing displacement and the drawing force will increase with the increase of the normal stress;The linear equation of the interface friction strength and the normal pressure is obtained by fitting,and the apparent cohesive force of the interface is 4.71 Kpa,and the apparent internal friction angle of the interface is6.772°;At the same time,it is found that the coefficient of the interface friction angle decreases with the increase of the overlying pressure,and the decrease range is from large to small.(2)The influence of the addition of basalt fiber geogreds on the mechanical properties of cement-stabilized macadam was explored through related mechanical properties tests(unconfined compressive strength,splitting test,compressive rebound modulus test,bending and tensile test).The test results show that although the addition of basalt fiber geogrid reduces the compressive strength and compressive resilience modulus of cement stabilized crushed stone to a certain extent,at the age of 90 days,the two are reduced by 3.8% and 4.0%,respectively.The splitting strength and flexural strength of the composite are increased by 11.5% and 28%,respectively,indicating that the addition of basalt fiber geogreds can significantly improve the tensile strength of the composite.(3)The influence of the addition of basalt fiber geogrid on its durability was explored through relevant durability tests(dry shrinkage test,temperature shrinkage test,freeze-thaw resistance test,fatigue test).The experimental results show that the addition of basalt fiber geogreds can significantly reduce the dry shrinkage coefficient and temperature shrinkage coefficient,and thus improve the dry shrinkage resistance and temperature shrinkage resistance.However,its frost resistance increased slightly,and its frost resistance coefficient increased by 2.8% at 28 d age.In the process of fatigue test,it is found that the fatigue action times of cemented-stabilized aggregates with basalt fiber geogreille are increased by nearly 50%.