Effect of 10-Year Outdoor Exposure and Curing Conditions on the Pore Structure Characteristics of Hardened Cement Mortar

Quy, Nguyen Xuan; Kim, Junho; Hama, Yukio

doi:10.3151/jact.16.461

Cited by 11 publications

(5 citation statements)

References 49 publications

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“…In addition, compared to the standard curing, there was the higher curing temperature in subsequent water curing environment, which is also helpful to improve the hydration rate and resistance to freeze-thaw of concrete [50]. By contrast, natural air curing involves inadequate moisture, so the internal pores of the concrete will experience a self-desiccation phenomenon, which makes the local pore structure of concrete loose and the pore size increase [51,52,53,54]. These larger local pores facilitate freeze-thaw damage in specific areas during the later-age freeze-thaw test, resulting in the decrease in the resistance to freeze-thaw of the concrete.…”

Section: Df Values and Results Analysismentioning

confidence: 99%

Freeze-thaw damage evaluation and model creation for concrete exposed to freeze–thaw cycles at early-age

Liu

Sas

et al. 2021

Construction and Building Materials

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Concrete subjected to freeze-thaw cycles action at early-age will suffer serious physical damage, resulting in degradation of the concrete's performance. The subsequent curing conditions after early-age freeze-thaw cycles (E-FTCs) are critical to the development of the properties of frost-damaged concrete. Four test environments were set up for this study, based on different numbers of E-FTCs and subsequent curing conditions. The later-age resistance to freeze-thaw of concrete exposed to E-FTCs was evaluated by analysing the influence of precuring times and curing conditions. Results show that the earlier the FTCs occur, the worse the later-age freeze-thaw resistance is. In particular, for the frost-damaged concrete with a pre-curing time of 18 h, its freeze-thaw resistance is significantly worse than that of other concretes that have a longer pre-curing time. The increase in the number of E-FTCs exacerbates the damage to early-age concrete, which causes the reduced laterage freeze-thaw resistance. Subsequent water curing can significantly improve the freeze-thaw resistance of damaged concrete, while air curing is the least effective. Based on previous freeze-thaw damage models, prediction models for concrete exposed to E-FTCs were created by using the test data obtained in this study. The critical pre-curing strengths which can ensure that the damaged concrete has satisfactory frost resistance at laterage were thus obtained. For concrete structures expected to experience E-FTCs, adequate pre-curing strength and good re-curing conditions are essential.Abbreviations: DF, Durability factor; E-FTC, Early-age freeze-thaw cycle; FTC, Freeze-thaw cycle; MLR, Mass loss rate; RDME, Relative dynamic modulus of elasticity; 10-WC, Cured in water to age 28 d after 10 E-FTCs; 20-SC, Cured in standard curing room to age 28 d after 20 E-FTCs; 20-WC, Cured in water to age 28 d after 20 E-FTCs; 20-NC, Cured in natural air to age 28 d after 20 E-FTCs.

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Section: Df Values and Results Analysismentioning

confidence: 99%

Freeze-thaw damage evaluation and model creation for concrete exposed to freeze–thaw cycles at early-age

Liu

Sas

et al. 2021

Construction and Building Materials

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“…where M ph is the modified maturity function using time, temperature, and humidity ( As mentioned above, it is clear that the pore structure change is significantly influenced by environmental conditions. Therefore, in this study, practical formulas such as the modified maturity as a function of time, temperature, and humidity based on the presented findings [40,41] are formulated by:…”

Section: Results For Pore Structure Change Due To Environmental Condimentioning

confidence: 99%

“…According to previous research [41], the change in the volume of 40-2000 nm diameter pores that corresponds to a specific temperature-humidity environment and water-to-cement ratio is obtained from:…”

Section: Results For Pore Structure Change Due To Environmental Condimentioning

confidence: 99%

“…Kamada et al [19] found that the relationship between the volume of 40-2000 nm diameter pores, the air-content-to-paste ratio, and the durability factor is represented by: According to previous research [41], the change in the volume of 40-2000 nm diameter pores that corresponds to a specific temperature-humidity environment and water-to-cement ratio is obtained from: ln…”

Section: Model For Predicting Frost Resistance Based On Pore Structurmentioning

confidence: 99%

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Distribution Map of Frost Resistance for Cement-Based Materials Based on Pore Structure Change

Quy

Noguchi

et al. 2020

Materials

Self Cite

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This paper presents a prediction method and mathematical model based on experimental results for the change in pore structure of cement-based materials due to environmental conditions. It focuses on frost damage risk to cement-based materials such as mortar. Mortar specimens are prepared using water, ordinary Portland cement, and sand and the pore structure is evaluated using mercury intrusion porosimetry. New formulas are proposed to describe the relationship between the pore structure change and the modified maturity and to predict the durability factor. A quantitative prediction model is established from a modified maturity function considering the influences of environmental factors like temperature and relative humidity. With this model, the frost resistance of cement-based materials can be predicted based on weather data. Using the prediction model and climate data, a new distribution map of frost damage risk is created. It is found that summer weather significantly affects frost resistance, owing to the change in pore structure of cement-based mortar. The model provides a valuable tool for predicting frost damage risk based on weather data and is significant for further research.

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“…Instead of chloride content decreasing monotonously with increasing distance from the exposed surface, a maximum phenomenon [10][11][12] has been reported by many studies [13][14][15][16][17][18], that is, chloride content first increases, reaches a climax, and then decreases. Affecting the accuracy of the service life prediction of concrete, the maximum phenomenon has gained increasing attention [19][20][21][22][23][24][25]. Capillary suction may be one major cause for the forming of chloride climax during cyclic wetting-drying, as has been supported by many studies [8,[26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Effect of Carbonation on Chloride Maximum Phenomena of Concrete Subjected to Cyclic Wetting–Drying Conditions: A Numerical and Experimental Study

Zhang²,

Zhang³

et al. 2022

Materials

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The combined action of chloride and carbonation generally accelerates chloride penetration in concrete. Plenty of studies have revealed a chloride maximum phenomenon in the chloride profiles of concrete under wetting and drying cycles, which affects the accuracy of the service life prediction of concrete structures. Carbonation is probably one of crucial factors inducing chloride maximum phenomena. To investigate the influence of carbonation on chloride distribution of concrete subjected to cyclic wetting–drying conditions, this study established a numerical model coupling carbonation effect, simulated chloride distribution at different carbonation degrees, and verified the simulation results with experimental results. The results show that a chloride peak appears in all predicted chloride profiles when carbonation effect is taken into account, and the higher the carbonation degree is, the more significant the chloride peak is. This demonstrates that carbonation can enhance the forming of chloride maximum phenomenon under cyclic wetting and drying. Moreover, the calculated results are highly consistent with the experimental results under different carbonation conditions, especially in terms of the peak chloride concentration and the corresponding depth. Furthermore, the significance degree of the chloride maximum phenomenon is closely related to some key parameters, such as CO2 concentration, environmental humidity, and temperature.

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Effect of 10-Year Outdoor Exposure and Curing Conditions on the Pore Structure Characteristics of Hardened Cement Mortar

Cited by 11 publications

References 49 publications

Freeze-thaw damage evaluation and model creation for concrete exposed to freeze–thaw cycles at early-age

Freeze-thaw damage evaluation and model creation for concrete exposed to freeze–thaw cycles at early-age

Distribution Map of Frost Resistance for Cement-Based Materials Based on Pore Structure Change

Effect of Carbonation on Chloride Maximum Phenomena of Concrete Subjected to Cyclic Wetting–Drying Conditions: A Numerical and Experimental Study

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