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在鲍尔斯(Powers)的一系列研究工作中,引入了静水压力这个概念,也就是砼冻结时,与基体中水份的迁移有关。按照这个模型,水泥浆中饱水毛细孔不能允许由于水转化成冰而产生的9%的体积膨胀,否则将产生裂纹。这样,多数过量的水被挤出毛细孔而流到其它地方。这种迁移产生静压力,其大小取决于温度降低的速率、迁移距离及基体的渗透性。后来,鲍尔斯(Powers)与哈姆(Helmth)合作,利用了渗透压力的概念来解释水向成冰毛细孔迁移的现象。毛细孔中的水含有数种可溶性物质。由于表面物理化学作用,孔的大小不
In Powers’ series of research work, the concept of hydrostatic pressure was introduced, which is related to the migration of water in the substrate when the concrete freezes. According to this model, saturated pores in the cement slurry cannot allow 9% volume expansion due to the conversion of water into ice, otherwise cracks will occur. In this way, most of the excess water is squeezed out of the capillary and flows elsewhere. This migration generates static pressure, the size of which depends on the rate of temperature decrease, the distance traveled, and the permeability of the matrix. Later, Powers collaborated with Helmth to use the concept of osmotic pressure to explain the migration of water into ice capillaries. The water in the pores contains several soluble substances. Due to surface physicochemical effects, the pore size is not