Experimental and modeling study on the triaxial mechanical behavior of sulfate-deteriorated mortar
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ORIGINAL ARTICLE
Experimental and modeling study on the triaxial mechanical behavior of sulfate-deteriorated mortar Yu Xiaotong . Li Chousheng . Zhao Yazhou . Zhang Yan . Liao Yingdi . Chen Da
Received: 5 May 2020 / Accepted: 7 September 2020 Ó RILEM 2020
Abstract Considering the significance of sulfate attack to structure durability and frequent existence of multiaxial loadings, it is relevant to study the triaxial mechanical behavior of sulfate-deteriorated cementitious materials. The triaxial compression tests with three confining pressures were conducted in previous study. To give a reliable constitutive model, this research investigated the triaxial mechanical behavior of sulfate-deteriorated mortar in experimental and modeling aspects. All stress–strain curves of the mortar samples immersed in 5% Na2SO4 solution up to 270 d were shown and analyzed. The ingress of sulfate decreased the axial strain at improvement stage, but slightly increased the strain at deterioration stage. The volume of mortar sample changed from contraction to dilation with loading, indicating a nonassociated flow rule. A nearly linear relationship between the square root of triaxial failure stress and elastic modulus of mortar was observed, proved by other research results as well. The lateral confinement
Y. Xiaotong L. Chousheng Z. Yazhou Z. Yan L. Yingdi C. Da (&) Key Laboratory of Coastal Disaster and Defence of Ministry of Education, Hohai University, Nanjing 210098, China e-mail: [email protected] Y. Xiaotong L. Chousheng Z. Yazhou Z. Yan L. Yingdi C. Da College of Harbor, Coastal, and Offshore Engineering, Hohai University, Nanjing 210098, China
attenuated the negative effect of sulfate deterioration on the two mechanical indexes. On the basis of elastoplasticity theory and experimental results, an elastoplastic model considering sulfate deterioration was proposed. The effect of sulfate deterioration was implemented to the elastic modulus, failure criterion and hardening law through 2nd polynomial. Numerical simulations showed that the proposed model can well reproduce the compression behavior of sulfatedeteriorated mortar with different confining pressures. Keywords Sulfate attack Cementitious materials Triaxial mechanical behavior Elastoplastic model
1 Introduction Cementitious materials are widely used in civil engineering standing in harsh environment, such as underground foundations, nuclear containments, and offshore structures. In the service life, the materials not only withstand complex stress states, for example, hydrostatic pressure and soil pressure, but suffer the surrounding chemical/physical deterioration, e.g., chloride corrosion, sulfate attack, carbonation, drying-wetting cycles, and etc. The sulfate attack is a main durability problem for structures in saline environment.
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Sulfate ions in the saline waters penetrate into the internal porous structure of cementitious materials, followed by a reaction with hydration pha
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