Experimental and Numerical Analysis on Coupled Hygro-Thermo-Chemo-Mechanical Effect in Early-Age Concrete

Zhao, Haitao; Jiang, Kaidi; Hong, Bin; Yang, Ruyi; Xu, Wen; Tian, Qinghua; Liu, Jiaping

doi:10.1061/(asce)mt.1943-5533.0003666

Cited by 28 publications

(5 citation statements)

References 51 publications

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“…At low Na 2 SO 4 concentrations (≤ 5 wt%), Cl − and SO 4 2 − gradually migrated into the concrete; however, SO 4 2 − preferentially reacted with C-S-H, CH, or Friedel’s salt to form Aft, and Friedel’s salt was effectively corroded away by Na 2 SO 4 . A portion of the Cl − was also released to form free Cl − [ 56 , 57 , 58 ], causing the Cl − concentration in the pores to increase. At the same time, corrosion products filled the concrete pores, cracks, and ITZ, which changed the pore distribution in these samples, specifically, this caused the transition from large pores to middle and small pores, thereby hindering Cl − migration.…”

Section: Discussionmentioning

confidence: 99%

Study on Concrete Deterioration in Different NaCl-Na2SO4 Solutions and the Mechanism of Cl− Diffusion

Zhang

Feng

et al. 2021

Materials

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The diffusion of sulfate (SO42−) and chloride (Cl−) ions from rivers, salt lakes and saline soil into reinforced concrete is one of the main factors that contributes to the corrosion of steel reinforcing bars, thus reducing their mechanical properties. This work experimentally investigated the corrosion process involving various concentrations of NaCl-Na2SO4 leading to the coupled erosion of concrete. The appearance, weight, and mechanical properties of the concrete were measured throughout the erosion process, and the Cl− and SO42− contents in concrete were determined using Cl− rapid testing and spectrophotometry, respectively. Scanning electron microscopy, energy spectrometry, X-ray diffractometry, and mercury porosimetry were also employed to analyze microstructural changes and complex mineral combinations in these samples. The results showed that with higher Na2SO4 concentration and longer exposure time, the mass, compressive strength, and relative dynamic elastic modulus gradually increased and large pores gradually transitioned to medium and small pores. When the Na2SO4 mass fraction in the salt solution was ≥10 wt%, there was a downward trend in the mechanical properties after exposure for a certain period of time. The Cl− diffusion rate was thus related to Na2SO4 concentration. When the Na2SO4 mass fraction in solution was ≤5 wt% and exposure time short, SO42− and cement hydration/corrosion products hindered Cl− migration. In a concentrated Na2SO4 environment (≥10 wt%), the Cl− diffusion rate was accelerated in the later stages of exposure. These experiments further revealed that the Cl− migration rate was higher than that of SO42−.

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Section: Discussionmentioning

confidence: 99%

Study on Concrete Deterioration in Different NaCl-Na2SO4 Solutions and the Mechanism of Cl− Diffusion

Zhang

Feng

et al. 2021

Materials

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“…The research in multifield modeling of early-age concrete is still ongoing. Zhao et al (2020Zhao et al ( , 2021 coupled the moisture transport field and the heat transfer field and performed an in-depth experimental investigation on the early-age development of temperature and the internal relative humidity. Their multifield-coupled model was shown to achieve high accuracy, compared with the testing results of high-performance concrete.…”

Section: Multifield-coupled Modeling Techniquesmentioning

confidence: 99%

“…The formulation of the multifield TCM model is shown in Figure 2. In previous studies (di Luzio & Cusatis, 2009a, 2009bZhao et al, 2020Zhao et al, , 2021 on multifield modeling of early-age concrete, the applicability of Fourier's law for heat transfer and Arrhenius's equation for hydration reaction were validated. These two constitutive equations are also adopted in this work to simulate the thermoand chemo-fields of the TCM model.…”

Section: Tcm Modelmentioning

confidence: 99%

Predicting early‐age stress evolution in restrained concrete by thermo‐chemo‐mechanical model and active ensemble learning

Liang

Chang

et al. 2022

Computer aided Civil Eng

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“…This is the case with highperformance concrete (HPC), which has very good compatibility, mechanical properties and impermeability and is very widely used in engineering. However, the low water-cement ratio and additives make the hydration reaction much faster, which leads to a substantial and rapid temperature drop and a large self-shrinkage [3]. Self-shrinkage of high-performance concrete under certain conditions can lead to excessive concrete stresses, which can lead to cracks [4,5].…”

Section: Introductionmentioning

confidence: 99%

Effect of Mineral Admixtures on the Mechanical and Shrinkage Performance of MgO Concrete

et al. 2023

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Shrinkage deformation of concrete has been one of the difficulties in the process of concrete performance research. Cracking of concrete caused by self-shrinkage and temperature-drop shrinkage has become a common problem in the concrete world, and cracking leads to a decrease in the durability of concrete and even a safety hazard. Mineral admixtures, such as fly ash and mineral powder, are widely used to improve the temperature drop shrinkage of mass concrete; fly ash can reduce the temperature rise of concrete while also reducing the self-shrinkage of concrete, there are different results on the effect of mineral powder on the self-shrinkage of concrete, but the admixture of fly ash will reduce the strength of concrete, and mineral admixtures have an inhibitory effect on the shrinkage compensation effect of MgO expander(MEA). The paper investigates the effect of mineral admixtures on the mechanical and deformation properties of C50 mass concrete with a MgO expander(MEA), aiming to determine the proportion of C50 mass concrete with good anti-cracking properties under working conditions. The experiments investigated the effect of fly ash admixture, mineral powder admixture and MgO expander admixture on the compressive strength and deformation of concrete under simulated working conditions of variable temperature and analyzed the effect of hydration of magnesite in MgO expander and pore structure of cement paste on deformation. The following main conclusions were obtained: 1. When the concrete compounded with mineral admixture was cured under variable temperature conditions, the compounded 30% fly ash and mineral powder decreased by 4.3%, 6.0% and 8.4% at 7d age, and the compounded 40% fly ash and mineral powder decreased by 3.4%, 2.8% and 2.3% at 7d age, respectively. The incorporation of MEA reduced the early compressive strength of concrete; when the total amount of compounding remained unchanged, the early compressive strength of concrete was gradually smaller as the proportion of compounding decreased. 2. The results of concrete deformation showed that when the temperature rose, the concrete expanded rapidly, and when the temperature dropped, the concrete also showed a certain shrinkage, and the deformation of concrete basically reached stability at 18d. 3. The compounding of 30% fly ash and mineral powder As the compounding ratio decreases, the deformation of concrete increases, and the 28d deformation of concrete with a compounding ratio of 2:1 is 280 × 10−6, while the final stable deformation of concrete with a compounding ratio of 2:1 in compounding 40% fly ash and mineral powder is the largest, with a maximum value of 230 × 10−6, respectively. Overall, the concrete with a total compounding of 30% and a compounding ratio of 2:1 has the best shrinkage resistance performance.

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Experimental and Numerical Analysis on Coupled Hygro-Thermo-Chemo-Mechanical Effect in Early-Age Concrete

Cited by 28 publications

References 51 publications

Study on Concrete Deterioration in Different NaCl-Na2SO4 Solutions and the Mechanism of Cl− Diffusion

Study on Concrete Deterioration in Different NaCl-Na2SO4 Solutions and the Mechanism of Cl− Diffusion

Predicting early‐age stress evolution in restrained concrete by thermo‐chemo‐mechanical model and active ensemble learning

Effect of Mineral Admixtures on the Mechanical and Shrinkage Performance of MgO Concrete

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