Viscoelasticity of Solidifying Porous Material-Concrete
Viscoelasticity of Solidifying Porous Material-Concrete
复制标题
凝固多孔材料-混凝土的粘弹性
DOI：
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发表时间：
1977
期刊：
影响因子：
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通讯作者：
Z. Bažant
中科院分区：
文献类型：
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作者：
Z. Bažant
将水化水泥浆体视为固体体积分数增加，材料在荷载作用下发生蠕变的变量复合材料，建立了龄期对线蠕变和弹性的影响形式。该公式基于三个假设：(1)不同时间固化的微量元素的平均应变相等；(2)固化物(水泥凝胶)的性质是时不变的；(3)固体颗粒在水泥凝胶中引起蠕变的迁移速度取决于加载时迁移通道的平均长度。第一个假设允许从建立的两个积分方程组中消除微观应力，该系统建立的是将应力和应变历史联系起来的。推导了一种新的蠕变函数形式，用水泥凝胶体积的增长和迁移通道长度的增加来表示老化效应。结果表明，在凝胶体积增长可以忽略的情况下，双幂定律是一种特例，给出了一个与凝胶体积增长相一致的推论，并与蠕变数据进行了比较。
The form of the age effect on linear creep and elasticity is established by treating the hydrating cement paste as a variable composite in which the volume fraction of solid grows while the material creeps under load. The formulation rests on three hypotheses: (1)The average strains in microelements solidified at various times are equal; (2)the properties of solidified matter (cement gel) are time-invariant; (3)the rate of migrations of solid particles causing creep in cement gel depends on the mean length of migration passages at the time of load application. The first hypothesis allows eliminating the microstresses from a system of two integral equations set up to relate stress and strain histories. A new form of the creep function is deduced, expressing the aging effect in terms of the growth of volume of cement gel and the increase of the migration passage length. It is shown that the double power law is obtained as a special case when the growth of gel volume is negligible, and a generalization consistent with growing gel volume is suggested and compared with creep data.