应力吸收防水粘结层防治反射裂缝性能的研究

为了防治旧水泥路面沥青加铺层反射裂缝的产生，研发了应力吸收防水粘结层（SAWI）。该材料是一种使用高弹改性沥青、砂粒式富沥青断级配沥青混合料，具有低模量、高韧性、高粘性、防渗等特点，可以有效的吸收由于旧水泥板运动产生的应力，阻止反射应力进一步向上传递。应用APA试验结果证明其疲劳寿命是普通沥青混凝土的3.32倍；渗水系数为0，可以防止水分进入路面结构，即使面层产生了裂缝仍然可以起到防水的作用；具有很好层间结合能力， 60℃的真空毛细管粘度超过30MPa?s；具有很好的低温性能，-10℃的弯曲破坏应变是规范要求的5.36倍。该夹层结构在几条高速公路中得到了应用，防治反射裂缝效果良好。

Study on Performance of Stress Absorbing Waterproof Interlayer (SAWI) for Preventing Reflection Cracking

To approach the reflection cracking problem in asphalt overlays systematically the properties of the materials intended to be used in an SAWI (Stress Absorbing Waterproof Interlayer) were first identified. Various load/structural models and laboratory equipment were used for this purpose. The SAWI layer was evaluated for its effectiveness against reflection cracking. A laboratory sample with an asphalt overlay over a jointed PCC slab was constructed and placed in an environmental chamber. Upgraded Asphalt Pavement Analyzer (APA) was used to simulate wheel load on the slab. The testing was conducted at 30℃ and cracking in the overlay was monitored using a sensitive video device. MTS was upgraded to evaluate the interfacial shear strength and laboratory testing was performed to determine the shear strength of the fabricated SAWI layer under an asphalt overlay. The results showed that the SAWI layer was highly effective in preventing reflection cracking in asphalt overlay. Comparing to a control test sample and a sample using a commercially available reflection cracking control material the SAWI layer provided for superior performance. A few field pavement sections utilizing the SAWI layer were constructed in the autumn 2006, field evaluations for it are all feasible, and the long-term observing is ongoing.