非饱水冻融作用下的古砖动弹性模量
Dynamic elastic modulus based on unsaturated water freeze-thaw action for ancient bricks

弹性模量是反映材料刚度的重要指标。自然界中雨淋和冻融导致古建筑砌体砖处于非饱水冻融状态。通过大气环境实验舱对古砖进行非饱水冻融作用下的饱和系数、饱水度、动弹性模量、相对动弹性模量等技术参数实验，分析了非饱水冻融作用下古砖弹性模量变化规律。实验结果表明，饱水度大于等于60%时，非饱水冻融导致古砖试件动弹性模量和相对动弹性模量数值均出现明显下降趋势；饱水度小于60%时，非饱水冻融对动弹性模量和相对动弹性模量数值影响较小。非饱水冻融作用下，古砖的初始抵抗风化能力大小是影响动弹性模量和相对动弹性模量数值的重要因素。同时，对非饱水冻融作用下反映古砖抵抗冻融损伤能力的极限饱水程度等关键参数进行了讨论。
Elastic modulus is one of the most important indexes to reflect material stiffness. Raining and freeze-thaw lead brick masonry to be in the state of unsaturated water freeze-thaw. The experiment aims to obtain the elastic modulus of ancient bricks under various unsaturated water freeze-thaw. The brick samples were put in the environmental chamber to carry out raining and freeze-thaw action. The experiment including saturated coefficient, saturated degree, dynamic elastic modulus and relative elastic modulus were carried out for these samples. Results show that the dynamic elastic modulus of the samples obviously decreases when saturated degree is equal to or larger than 60%; the elastic modulus of the samples have no significant change when saturated degree is less than 60%, and the samples break when their saturated degree reached a certain value. This paper also discusses parameters like limit saturated degree, which reflect the freeze-thaw resistance for ancient bricks.