模型再生混凝土单轴受压性能细观数值模拟

提出了模型再生混凝土的概念,根据各相介质细微观力学参数和本构关系建立了数值模型,对再生混凝土的破坏机理进行了仿真分析.通过变化再生粗骨料取代率、新硬化水泥砂浆强度、老硬化水泥砂浆强度、老硬化水泥砂浆厚度以及界面过渡区(ITZ)强度等参数,对模型再生混凝土单向受压性能进行了对比分析.结果表明:新硬化水泥砂浆和老硬化水泥砂浆强度对混凝土的初始弹性模量和峰值应力有较大影响,老硬化水泥砂浆厚度对模型再生混凝土的初始弹性模量和峰值应变有一定影响,界面过渡区的强度对再生混凝土的初始弹性模量、峰值应力和峰值应变的影响不显著.

Meso level Numerical Simulation on Mechanical Properties of Modeled Recycled Concrete Under Uniaxial Compression

Recycled concrete is often considered as a five-phase composite construction material, and a modeled recycled concrete is newly proposed in this paper. According to the meso- and micro-level mechanics parameters and constitutive relationships of the five-phase medium materials of recycled concrete, the mechanical properties of modeled recycled concrete under uniaxial compression is numerically simulated, and the failure mechanism of recycled concrete is preliminarily investigated. This paper discusses the effect of relevant parameters (i.e., the replacement ratio of recycled coarse aggregate, the strength of new hardened cement paste, the strength of old hardened cement paste, the thickness of old hardened cement paste, and the strength of interfacial transition zones) on the mechanical properties of modeled recycled concrete under uniaxial compression. The results of varying parameter analysis obtained from numerical simulation indicate that the strength of new hardened cement paste and old hardened cement paste have a remarkable influence on the initial elastic modulus and peak stress. The thickness of the old cement paste has some certain influence on the initial elastic modulus and peak strain. Furthermore, the influence of the strength of interfacial transition zones on the initial elastic modulus, peak stress and peak strain is not distinctive.