钢渣沥青混合料薄层罩面层间剪切性能研究

为了探究钢渣沥青混合料薄层罩面层间剪切破坏机理,设计一种间断级配钢渣沥青混合料和两种构造深度的表面层,研究表面层构造深度、温度、SBR改性乳化沥青用量和应力比对钢渣薄层罩面层间剪切性能的影响。通过马歇尔稳定度试验、冻融劈裂试验和动稳定度试验评价薄层罩面及表面层沥青混合料的基本路用性能,直剪试验和剪切疲劳试验评价薄层罩面层间抗剪切性能。研究结果表明:钢渣集料的压碎值和磨耗值明显低于石灰岩集料,且与沥青的粘附性好,使得钢渣沥青混合料的路用性能优异;层间抗剪强度主要受温度控制,在相同测试温度下,随着黏结材料用量增加,表面层与薄层罩面的层间接触状态得到改善,从而提高了抗剪强度,但过量的黏结材料在表面层与薄层罩面之间形成滑动层,导致构造深度对层间剪切强度的作用减弱;薄层罩面的层间剪切疲劳寿命随应力比的升高而降低,通过剪切疲劳试验得到了疲劳寿命方程。

Interlayer Shear Performance of Steel SlagAsphalt Mixture Thin Overlay

In order to explore the shear failure mechanism between thin overlay of steel slag asphalt mixture, a gap graded steel slag thin asphalt overlay and dense graded surface layers with different texture depth were designed. The effects of texture depth, temperature, styrene-butadiene rubber modified emulsified asphalt dosage and stress ratio on shear performance between thin layers of steel slag were studied. Marshall stability test, freeze-thaw splitting test and dynamic stability test were used to evaluate the road performance of asphalt mixture. Direct shear test and shear fatigue test were used to evaluate the interlayer shear performance between thin overlay and surface layers. The results show that the crushing value and abrasion of steel slag aggregate are obviously lower than those of limestone aggregate, and the adhesion of steel slag/asphalt is much better than that of limestone/asphalt, which makes the pavement performance of steel slag asphalt mixture excellent. Interlayer shear strength is mainly controlled by test temperature. At the same temperature, the interlayer contact state between the surface layer and the thin overlay is improved with increase of tack coat application rate, the shear strength is improved. However, excessive tack coat forms slip layer between the surface layer and the thin overlay, which weakened the influence of the texture depth on interlayer shear strength. Through shear fatigue test, the shear fatigue life of thin overlay decreases with the increase of stress ratio. The fatigue life equation is obtained by shear fatigue test.