Study On The Mechanical Properties Of Rubber Basalt Fiber Composite Modified Cement Stabilized

Cement stabilized crushed stone,as a surface material for high-speed railway roadbed in China,has the advantages of high strength,good permeability and frost resistance.However,it also has the disadvantages of low ductility and easy cracking.In order to improve the comprehensive performance of cement stabilized crushed stone,the optimal ratio of surface fillers for high-speed railway subgrade bed that takes into account strength,shrinkage,and frost resistance is determined.This article takes cement stabilized crushed stone as the research object,and uses rubber powder and basalt fiber to composite modify it.Through orthogonal experiments,the effects of rubber replacement amount,basalt fiber length,basalt fiber content,and compaction degree on the unconfined compressive strength are studied,and the optimized material mix ratio is selected.Subsequent research will optimize the unconfined compressive strength,splitting strength,dry shrinkage deformation,and strength changes of the material after multiple freeze-thaw cycles.The main research findings are as follows:(a)Using the 7d unconfined compressive strength as the performance index,the effects of four influencing factors on the performance index were studied:cement content,basalt fiber content,basalt fiber length,and compaction degree.Select the optimal mixture material combination through orthogonal test results,validation test results,and relevant specifications:5%cement content,0.3%fiber content(9mm fiber length),and 97%compaction.(b)The influence of rubber powder and basalt fiber on the strength performance of rubber basalt fiber cement stabilized crushed stone was studied through indoor experiments.The results indicate that rubber has a negative impact on the strength of cement stabilized crushed stone,while basalt fibers have a positive impact on the strength of older cement stabilized crushed stone.(c)The influence of the combined action of rubber powder and basalt fibers on the compressive strength,splitting strength,and strength performance of cement stabilized crushed stone after freeze-thaw cycles was explored through indoor experiments.The ratio K of splitting strength to unconfined compressive strength was introduced as a parameter for crack resistance performance.The research results indicate that the composite modification of rubber and basalt fibers weakens the strength of cement stabilized crushed stone,but improves the frost resistance and crack resistance of the sample.(d)A dry shrinkage test was conducted on rubber and basalt fiber composite modified cement stabilized crushed stone.The test results showed that the dry shrinkage performance of the sample was superior to that of ordinary cement stabilized crushed stone under 10%,30%,and 45%rubber replacement rates.The dry shrinkage performance of cement stabilized crushed stone under 20%rubber replacement rate was very close to that of ordinary cement stabilized crushed stone.Rubber and basalt fibers can alleviate the dry shrinkage deformation of cement stabilized crushed stone.