考虑多尺度非均质性的混凝土传输性能预测模型

Modelling of Concrete Transport Property by Considering Multi-scale Heterogeneous Characteristics

以混凝土中离子传输性能的预测为例,基于微观到宏观的代表体积单元,分析了多尺度非均质性对传输性能预测的影响,建立了混凝土多尺度传输性能预测模型.相较于传统多尺度模型,本模型在微观尺度上考虑了随水泥水化程度变化的物质组成与净浆层级离子扩散系数的关系,在细观和宏观尺度上分析了粗细骨料界面过渡区、不规则骨料形状和多离子耦合效应对混凝土层级传输性能的影响.选取氯离子扩散系数、侵蚀深度为验证指标,通过对比各尺度下的模型预测值和试验值,验证了多尺度模型的可靠性.基于此模型,各尺度下的物质传输规律可得到深入探讨和高效印证.本研究也为离子、水分、气体等物质在混凝土中的传输性能预测提供了一个新的多尺度研究框架.

A multi‑scale model for concrete transport property prediction is developed by electing representative elements from micro to macro scale.Taking ionic diffusivity prediction as an example,the model comprehensively analyses the influence of inhomogeneity on the transport properties at different levels.Compared with the traditional model,new proposed model not only considers the influence of the hydration process at the microscopic scale,but also further analyses the influence of interfacial transition zones,aggregate shapes and the multi‑species ions interaction at the mesoscopic and macroscopic scales.The paper verifies the reliability of the model at each scale by comparing the predicted and experimental results of chloride diffusivities in concrete.Based on the proposed model,transport properties at different scales can be comprehensively revealed and analyzed.The present work also hopes to provide a novel multi‑scale framework to predict the transport mechanism of concrete.