高温后混凝土断裂韧度及软化本构曲线确定

Determination of Residual Fracture Toughness and Softening Traction separation Law of Post fire Concrete

摘要:

沿用常温下混凝土双线性软化本构曲线形式，对高温后混凝土软化特性进行研究.引入直接影响软化曲线形状的参数λ，结合高温后楔入劈拉试验中确定的起裂韧度与失稳韧度以及失稳韧度、起裂韧度、黏聚韧度三者之间的定量关系，调整参数λ，得到了与实测结果相符的双线性软化本构曲线形状.研究表明，由常温下混凝土材料试验得到的软化本构曲线经过小幅调整，仍能够较好地描述本试验中高温后混凝土的软化特性.

Abstract:

Investigations on the softening feature of post fire concrete was implemented in present research by adopting the bilinear softening traction separation law at room temperature. A new parameter λ, which directly influenced on the shape of softening curve, was introduced. According to initial fracture toughness and unstable fracture toughness determined by the wedge splitting method and the quantitative relationship among initial fracture toughness, unstable fracture toughness, and cohesive fracture toughness, the softening constitutive curve of post fire concrete was obtained through adjusting the parameter λ. It is concluded that the softening traction separation law obtained at room temperature with minor adjustments can also be applied to describing the softening feature of post fire concrete.