Chen Depeng, Zhu Qilin, Zong Zhifang, Xiang Tengfei, Liu Chunlin
School of Architectural and Civil Engineering, Anhui University of Technology, Ma'anshan 243032, China.
Institute of Green Building Materials, Anhui University of Technology, Ma'anshan 243032, China.
Materials (Basel). 2019 Dec 20;13(1):37. doi: 10.3390/ma13010037.
A crack caused by shrinkage could remarkably increase the permeability, heavily deteriorate the durability, and heavily deteriorate the service life of a concrete structure. However, different forms of thermal shrinkage can be predicted by directly applying a temperature load on a node. The prediction of moisture-induced stresses in cement-based materials by using the common finite element method (FEM) software is a big challenge. In this paper, we present a simple numerical calculation approach by using the proposed coefficient of hygroscopic expansion (CHE) to predict the moisture-induced deformation of concrete. The theoretical calculation formula of the linear CHE (LCHE) of cement-based material was deduced based on the Kelvin-Laplace equation and the Mackenzie equation. The hygroscopic deformation of cement mortar was investigated by inversion analysis; based on the results, the LCHE could be determined. Moreover, a case analysis of the application of LCHE to concrete is also conducted. The simulated results of concrete shrinkage were close to the experimental ones. As a whole, it is feasible to predict the drying shrinkage of concrete through simple calculation by using the proposed LCHE, which is also beneficial to the direct application of moisture loads on nodes in finite element analysis (FEA).
由收缩引起的裂缝会显著增加混凝土结构的渗透性，严重降低其耐久性和使用寿命。然而，通过直接在节点上施加温度荷载，可以预测不同形式的热收缩。使用通用有限元方法（FEM）软件预测水泥基材料中水分诱导的应力是一项巨大挑战。在本文中，我们提出了一种简单的数值计算方法，通过使用所提出的吸湿膨胀系数（CHE）来预测混凝土的水分诱导变形。基于开尔文 - 拉普拉斯方程和麦肯齐方程推导了水泥基材料线性吸湿膨胀系数（LCHE）的理论计算公式。通过反演分析研究了水泥砂浆的吸湿变形；基于这些结果，可以确定LCHE。此外，还对LCHE在混凝土中的应用进行了案例分析。混凝土收缩的模拟结果与实验结果相近。总体而言，使用所提出的LCHE通过简单计算来预测混凝土的干燥收缩是可行的，这也有利于在有限元分析（FEA）中将水分荷载直接应用于节点。
