A time−space porosity computational model for concrete under sulfate attack  

作　　者：Hui SONG Jiankang CHEN 

机构地区：[1]Jiangxi Provincial Key Laboratory of Hydraulic&Civil Engineering Infrastructure Security,Nanchang Institute of Technology,Nanchang 330099,China [2]Zhejiang Provincial Engineering Research Center for the Safety of Pressure Vessel and Pipeline,Ningbo University,Ningbo 315211,China [3]Ningbo University Donghai Academy,Ningbo 315211,China

出　　处：《Frontiers of Structural and Civil Engineering》2023年第10期1571-1584,共14页结构与土木工程前沿（英文版）

基　　金：support from the National Natural Science Foundation of China(Grant Nos.11832013,52168030);the Education Department of Jiangxi Province Science and Technology Project(No.211909);K.C.Wong Magna Fund in Ningbo University,and the project of the Key Laboratory of Impact and Safety Engineering(Ningbo University),Ministry of Education(No.202004).

摘　　要：The deterioration of the microscopic pore structure of concrete under external sulfate attack(ESA)is a primary cause of degradation.Nevertheless,little effort has been invested in exploring the temporal and spatial development of the porosity of concrete under ESA.This study proposes a mechanical–chemical model to simulate the spatiotemporal distribution of the porosity.A relationship between the corrosion damage and amount of ettringite is proposed based on the theory of volume expansion.In addition,the expansion strain at the macro-scale is obtained using a stress analysis model of composite concentric sphere elements and the micromechanical mean-field approach.Finally,considering the influence of corrosion damage and cement hydration on the diffusion of sulfate ions,the expansion deformation and porosity space−time distribution are obtained using the finite difference method.The results demonstrate that the expansion strains calculated using the suggested model agree well with previously reported experimental results.Moreover,the tricalcium aluminate concentration,initial elastic modulus of cement paste,corrosion damage,and continuous hydration of cement significantly affect concrete under ESA.The proposed model can forecast and assess the porosity of concrete covers and provide a credible approach for determining the residual life of concrete structures under ESA.

关 键 词：expansion deformation POROSITY internal expansion stress external sulfate attack mechanical–chemical coupling model 

分 类 号：TU528[建筑科学—建筑技术科学]