半刚性基层表面抗冲刷性能试验与分析

Experiment and Analysis of Anti-erosion Performance of Semi-rigid Base Surface

路面面层与基层界面之间积存的自由水因压力变化而高速流动并产生泵吸效应,将冲刷基层表面并导致路面损坏。为评估半刚性基层表面抗冲刷性能和防冲刷措施效果,基于半刚性基层材料的冲刷原理,利用混凝土振动台、沥青混合料车辙试验机进行振动水流冲刷和轮碾冲刷试验。通过两种基层材料、3种防冲刷措施的试验对比,确认水泥稳定级配碎石的抗冲刷性能优于水泥稳定砂砾;乳化沥青透层、土工布对减少半刚性基层材料的表面冲刷有较好的效果,冲刷量可下降60%~80%以上,最高降低94.4%;按抗冲刷效果排序,乳化沥青透层+土工布>土工布>乳化沥青透层;与未冻融的试件相比,冻融试件的冲刷量稍有增大;冻融循环条件下,所采用的三种抗冲刷措施效果保持良好。对于水泥混凝土路面,设置缩缝传力杆时,相对无传力杆路面,冲刷量可减少40.7%~66.3%。试验结果表明:振动水流冲刷试验的基层材料冲刷量总体大于轮碾冲刷试验结果,但总体规律一致。在无法定量分析半刚性基层材料抗冲刷性能的情况下,两种冲刷试验方法能够对基层材料的抗冲刷性能和防冲刷效果进行对比分析。

The free water accumulated between pavement surface and base can flow at high speed due to differential pressures, producing a pumping effect. This may scour surface of base, causing damage to the road surface. In order to evaluate the anti-erosion performance and anti-scouring effect of semi-rigid base, based on the principle of the scouring of semi-rigid base material, the vibrating water flow erosion test and wheel rolling scouring tests are carried out by using concrete shaking table and asphalt mixture rutting tester. Through comparison of the tests on 2 kinds of base materials and 3 anti-erosion measures, it is confirmed that the erosion resistance of cement stabilized graded crushed stone is superior to that of cement stabilized gravel. The use of emulsified asphalt penetration treatment and geotextiles can produce a good effect on reducing the surface erosion of semi-rigid base material, and the scouring mass of the base material can usually be reduced by 60% to 80% or more, in one case up to 94.4%. In terms of the anti-erosion effect, ＂emulsified asphalt permeation treatment ＋ geotextiles＂ is the most superior solution, followed by applying geotextiles alone then the use of emulsified asphalt permeation treatment alone. Compared with the non-frozen-thawed specimen, the scouring mass of the frozen-thawed specimen increased slightly. Under the condition of freeze-thaw cycle, the effects of the 3 anti-erosion measures remain promising. For the cement concrete pavement, applying dowel bar of contraction joints can reduce erosion by 40.7% to 66. 3%. The test result shows that （ 1 ） the scouring mass of the base material in the vibration water flow scouring test is larger than that of the wheel rolling scouring test, while the overall trend remains constant ; （2） under the condition of unable conduct the anti-erosion performance quantitative analysis of anti-erosion performance of semi-rigid base materials, either one of the 2 erosion test methods can be utilized to analyze and compare the erosion resistance and antierosion effect of the base materials.