含水率对级配碎石动回弹模量影响的试验研究

Research on Influence of Moisture Content on Dynamic Rebound Modulus of Graded Crushed Stone

为了更好地确定含水率对级配碎石动回弹模量的影响,通过室内动三轴试验测定得到不同含水率和应力状态下级配碎石材料的动回弹模量。试验分析可得,随着含水率的不断增加,级配碎石动回弹模量逐渐减小,在98%的压实度下,当含水率从OMC+1%减小到OMC-1%时,级配碎石动回弹模量平均增大幅度为20. 9%;当含水率从OMC减小到OMC-1%时,级配碎石动回弹模量平均增大幅度为14. 6%。在沥青路面结构设计中,采用的动回弹模量是基于最佳含水率条件下的试验值,研究表明:道路运营期间的级配碎石含水率往往大于设计时采用的最佳含水率,其动回弹模量小于设计采用的动回弹模量值;动回弹模量的折减会削弱改善路基的效果,难以发挥提高路基顶面回弹模量的改善作用,可能造成路面结构早期破坏。

In order to define the influence of moisture content on dynamic rebound modulus of graded crushed stone,this paper obtains the dynamic resilience modulus of the graded macadam material under different moisture content and stress conditions by indoor dynamic tri-axial test.The experimental analysis showed that as the water content increases,the moisture content of the graded crushed stone gradually decreases.Under the98%compaction degree,when the water content decreased from OMC+1to OMC-1%,the average increase of the elastic modulus of the crushed stone was20.9%.When the water content decreases from OMC to OMC-1%,the average moisture content of the graded crushed stone increases by14.6%.In the design of asphalt pavement structure,the dynamic rebound modulus was based on the experimental value under the optimal moisture content.The research indicates that the moisture content of the graded crushed stone during road operation was often greater than the optimal moisture content used in the design.The dynamic modulus of the dynamic rebound modulus was smaller than the dynamic rebound modulus value used in the design.The reduction of the dynamic resilience modulus will weaken the effect of subgrade improvement,and it is difficult to improve the rebound modulus of the top surface of the roadbed,which may cause early damage to the pavement structure.