桥面防水材料拉伸性能及其评价指标

Tensile Properties and Its Evaluated Indexes of Waterproofing Material for Bridge Decks

进行了拉伸速度、试件宽度与长度等因素对典型桥面防水材料拉伸强度及断裂延伸率的影响规律试验;分析了桥面防水层在基层存在裂缝和桥面存在负弯矩情况下的受力特征,由此提出了桥面防水材料拉伸性能的评价指标。结果表明:防水材料试件随拉伸速度变化而变化,速度较大时,试验结果不稳定;断裂延伸率与试件宽度相关性不大,而拉伸强度与试件宽度成正比;断裂延伸率随着拉伸长度的增加而逐渐减小,但强度没有明显的规律性;试件老化对其拉伸强度和断裂延伸率均有显著影响,材料的强度和断裂延伸率比未老化前分别降低了10.9%和25.0%;同时考虑基层存在裂缝和桥面存在负弯矩时,可以计算桥面防水材料的抗拉强度标准。经综合分析,确定桥面防水材料拉伸试验速度为100 mm.min-1,试件宽度为50 mm,长度为180 mm;材料抗拉强度指标为36 N.cm-1。

Tests on the influencing rules of pulling speeds, specimen widths and lengths to tensile strength and fracture elongation were studied. Moreover, the force characteristics for bridge decks with negative moment and the cracks in base course were analyzed. Then, the evaluation indexes of tensile properties of waterproofing material for bridge decks were proposed. The results show that the waterproofing material specimens are subject to the changes of pulling speeds and the uncertainty attends test results in the relative high speed; the fracture elongations correlated weakly with specimen widths, hut tensile strengths are directly proportional to speciemen widths; the fracture elongation reduces with the stretching length increasing gradually, however, the material intensity has not appeared any obvious regularity. Specimen aging has a significant impact on its tensile strength and fracture elongation, which show the material strength and fracture elongation decrease 10. 9% and 25.0% respectively after aging. Taking into account of cracks in base course and negative moment for the bridge decks, the standard of tensile strength of waterproofing material for bridge decks can be calculated. By analyzing comprehensively, the pulling test speed of 100 mm·min^-1 , specimen width of 50 mm, length of 180 mm, material tensile strength index of 36 N·cm^-1 for waterproofing material in bridge decks are gained.