Purpose

This paper aims to propose the five-phase sphere equivalent model of recycled concrete, which can be used to deduce the theoretical formulas for the Poisson’s ratio and effective elastic modulus.

Design/methodology/approach

At a mesoscopic level, the equivalent model converts the interfacial layer, which consists of the new interfacial transition zone (ITZ), the old mortar and the old (ITZ), into a uniform equivalent medium. This paper deduces a strength expression for the interfacial transition zone at the microscopic level using the equivalent model and elastic theory. In addition, a new finite element method called the base force element method was used in this research.

Findings

Through numerical simulation, it was found that the mechanical property results from the five-phase sphere equivalent model were in good agreement with those of the random aggregate model. Furthermore, the proposed model agree on quite well with the available experimental data.

Originality/value

The equivalent model can eliminate the influence of the interfacial layer on the macroscopic mechanical properties, thereby improving the calculation accuracy and computational efficiency. The proposed model can also provide a suitable model for multi-scale calculations.

中文翻译：

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再生混凝土五相球等效模型及基于基力元法的数值模拟

目的

本文旨在提出再生混凝土的五相球等效模型，该模型可用于推导泊松比和有效弹性模量的理论公式。

设计/方法/方法

在细观层面，等效模型将界面层转换为均匀等效介质，界面层由新界面过渡区 (ITZ)、旧砂浆和旧界面 (ITZ) 组成。本文利用等效模型和弹性理论在微观层面推导出界面过渡区的强度表达式。此外，本研究还使用了一种新的有限元方法，称为基力元法。

发现

通过数值模拟发现，五相球等效模型的力学性能结果与随机集料模型的力学性能结果吻合较好。此外，所提出的模型与可用的实验数据非常吻合。

原创性/价值

等效模型可以消除界面层对宏观力学性能的影响，从而提高计算精度和计算效率。所提出的模型还可以为多尺度计算提供合适的模型。