论文部分内容阅读
目前,用于混凝土桥面或建筑物屋面的防水体系一般都是采用基于正交各向异性沥青膜;其中,苯乙烯-丁二烯-苯乙烯共聚物(SBS)和无规聚丙烯(APP)聚合物改性沥青膜应用范围比较广,但存在自底向上的压力导致膜下形成鼓泡。该文通过弹性力学建模与试验来研究它的扩散机理。为了研究复杂平面应力状态下SBS膜的材料性能,通过双轴拉伸试验对聚合物改性沥青防水卷材(PBM)的正交各向异性力学性能进行试验。然后,对测得的应力-应变数据进行分析,确定纵向和横向的材料特性常数。在混凝土板上进行鼓泡试验,通过控制PBM和混凝土板之间的压力来进行鼓泡扩散机理研究。结果发现:鼓泡在纵向和横向的扩散比值与纵向和横向弹性模量的比值相当。根据PBM的正交各向异性材料特性,通过对椭圆形鼓泡扩散过程观察,提出一个新的模型确定椭圆鼓泡的扩散能量。
At present, waterproofing systems used for concrete deck or building roof are generally based on orthorhombic anisotropic asphalt film; among them, styrene-butadiene-styrene copolymer (SBS) and random polypropylene ) Polymer modified asphalt membranes are widely used, but there is a bottom-up pressure that causes bubble formation under the membrane. This paper studies its diffusion mechanism through the modeling and experiment of elasticity. In order to study the material properties of SBS films under complex plane stress conditions, the mechanical properties of the polymer modified bitumen membrane (PBM) by orthogonal anisotropy were tested by biaxial tensile test. Then, the measured stress-strain data are analyzed to determine the material properties constants in the longitudinal and transverse directions. Bubbling tests were carried out on concrete slabs to investigate the bubble diffusion mechanism by controlling the pressure between the PBM and the concrete slab. The results show that the ratio of the bubble diffusion in the longitudinal and transverse directions is comparable to the ratio of the longitudinal and transverse elastic moduli. According to the characteristics of the orthotropic material of PBM, a new model was proposed to determine the diffusion energy of elliptical bubbling by observing the bubbling diffusion process of elliptical bubble.