Numerical investigation of the external sulfate attack induced expansion response of cement paste by using crystallization pressure. (16th January 2019)

• Record Type: Journal Article
• Authors: Yin, Guang-Ji; Zuo, Xiao-Bao; Sun, Xiang-Hua; Tang, Yu-Juan
• Is Part Of: Modelling and simulation in materials science and engineering. Volume 27:Number 2(2019)
• Publication Date: 2019-01-16
• Subjects: external sulfate attack -- hardened cement paste -- expansion response -- crystallization pressure -- macro- and microscopic model -- representative volume element; Materials -- Mathematical models -- Periodicals; Matériaux -- Modèles mathématiques -- Périodiques; Materials -- Mathematical models; Periodicals; 620.00113
• DOI: 10.1088/1361-651X/aaf76a
• Languages: English
• ISSNs: 0965-0393

Abstract

Abstract: A series of macro- and microscopic models have been proposed to numerically investigate the expansion response in hardened cement paste (HCP) caused by external sulfate attack (ESA). In the models, a HCP cylindrical specimen and a representative volume element (RVE) are respectively chosen as macroscopic and microscopic objects. Numerical simulation on the expansion response in the HCP specimen immersed into Na2 SO4 solution is performed. The results show that the macroscopic and microscopic expansion responses in HCP induced by crystallization pressure are different. At the macroscale, the stress state (the radial, hoop and axial stresses) of HCP in the surface layer of the specimen transforms from a triaxial tension to tension–compression–tension state, and further becomes tension–compression–compression. But, the HCP is always in a triaxial tension state in the interior of the specimen without ESA. At the microscale, the hoop tensile stress in RVE increases rapidly with immersion time and is responsible for the initiation of microcracks in the cement paste of RVE. By comparing the macroscopic and microscopic expansion responses, the microscopic stress is larger than the macroscopic stress in the sulfate corrosion zone of the specimen. It indicates that, the analysis on the ESA-induced damage of HCP needs to consider both the macroscopic and microscopic expansive stresses.