无黏结级配碎石基层回弹变形行为研究

Study on Rebound Deformation Behavior of Unbonded Graded Crushed Stone Base

使用UTM试验仪对采用不同粗细骨料含量与含水率的级配碎石进行加载,研究级配碎石的回弹变形影响因素,并通过CBR试验进行类比分析,为级配碎石作为道路基层实际施工应用中的设计提供合理参数,并对比得出最佳级配参数与含水率配比。试验结果表明:级配碎石的回弹模量总体低于半刚性基层材料,并显示为较为显著的非线性;但级配碎石在荷载作用下的抗变形能力较大;级配碎石弹性模量随着含水率的增加而减小,随着粗骨料含量的增加而增加。级配碎石的CBR值受集料级配的影响较大,受含水率的影响较小。所以,如果在道路设计中使用级配碎石作为基层能够缓解半刚性基层沥青路面的裂缝反射情况,还可以利用其抗疲劳的特性在道路使用中延长道路使用寿命以及增加其透水率,防止地下水冻融循环对道路造成影响。

The UTM tester is used to load the Graded Macadam with different coarse and fine aggregate content and moisture content, study the influencing factors of rebound deformation of Graded Macadam,and make analogy analysis through CBR test, so as to provide reasonable parameters for the design of Graded Macadam as the actual construction application of road base, and compare the best gradation parameters and moisture content ratio.The test results show that the resilient modulus of graded crushed stone is generally lower than that of semi-rigid base material, and shows significant nonlinearity;However, the deformation resistance of graded crushed stone under load is large;The elastic modulus of graded crushed stone decreases with the increase of moisture content and increases with the increase of coarse aggregate content. The CBR value of graded crushed stone is greatly affected by aggregate gradation and less affected by moisture content. Therefore, if the graded crushed stone is used as the base in the road design, it can alleviate the crack reflection of the semi-rigid base asphalt pavement, and can also use its anti fatigue characteristics to prolong the service life of the road and increase its water permeability, so as to prevent the impact of the freezing and thawing cycle of groundwater on the road.