Effect of water-to-cement ratio induced hydration on the accelerated carbonation of cement pastes

Mehdizadeh, Hamideh; Jia, Xiaoxiao; Mo, Kim Hung; Ling, Tung-Chai

doi:10.1016/j.envpol.2021.116914

Cited by 65 publications

(13 citation statements)

References 53 publications

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“…The test results show that the factors that changed the high temperature resistance of concrete were not only the water/cement ratio but also the plastering layer, and whether the plastering layer improved the high-temperature resistance of concrete depended on the water/cement ratio of concrete. For concrete with a high water/cement ratio, most cement was hydrated during the 28 days curing [30,31], so the concrete lacked reactants to continue hydration at high temperatures. When the water/cement ratio dropped, the cement of the concrete was not completely hydrated during the 28 days curing, and the compressive strength of the concrete even increased at 400 • C due to the Van der Waals force [28,32] and hydration of the unhydrated cement.…”

Section: Discussion Of Resultsmentioning

confidence: 99%

“…When the water/cement ratio was 0.30, the compressive strength of concrete decreased first, then rose, and then fell again with the increase of temperature. This phenomenon may be attributed to two reasons: (i) With the decrease of water/cement ratio, the number of unhydrated cement particles of concrete increased [30,31], and high temperature promoted the continuous hydration of unhydrated cement particles [3], so concrete with the lowest water/cement ratio (0.30) can realize the improvement of compressive strength in high temperatures. (ii) The improvement of compressive strength at high temperature can be attributed to the Van der Waals force [28,32].…”

Section: Compressive Strengthmentioning

confidence: 99%

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High Temperature Degradation Mechanism of Concrete with Plastering Layer

Liu

Chen

2022

Materials

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At present, the research on the high temperature degradation of concrete usually focuses on only the degradation of concrete itself without considering the effect of the plastering layer. It is necessary to take into account the influence of the plastering layer on the high temperature degradation of concrete. With an increase in the water/cement ratio, the explosion of concrete disappeared. Although increasing the water/cement ratio can alleviate the cracking of concrete due to lower pressure, it leads to a decrease in the mechanical properties of concrete after heating. It is proved that besides the water/cement ratio, the apparent phenomena and mechanical properties of concrete at high temperature can be affected by the plastering layer. The plastering layer can relieve the high temperature cracking of concrete, and even inhibit the high temperature explosion of concrete with 0.30 water/cement ratio. By means of an XRD test, scanning electron microscope test and thermogravimetric analysis, it is found that the plastering layer can promote the rehydration of unhydrated cement particles of 0.30 water/cement ratio concrete at high temperature and then promote the mechanical properties of concrete at 400 °C. However, the plastering layer accelerated the thermal decomposition of C-S-H gel of concrete with a water/cement ratio of 0.40 at high temperature, and finally accelerate the decline of mechanical property of concrete. To conclude, the low water/cement ratio and plastering layer can delay the deterioration of concrete at high temperature.

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Section: Discussion Of Resultsmentioning

confidence: 99%

Section: Compressive Strengthmentioning

confidence: 99%

High Temperature Degradation Mechanism of Concrete with Plastering Layer

Liu

Chen

2022

Materials

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“…This suggested that aer carbonation, the C-S(A)-H chain shrank and the non-bridging oxygen on the silicate sites decreased. 36,[60][61][62] Then, the mineral characteristics of CaCO 3 (Fig. 5-7) were investigated.…”

Section: Chemical Outcomesmentioning

confidence: 99%

“…[30][31][32][33][34] Calcite has been observed in most experiments of carbonation of CBMs. [35][36][37][38] Insufficient attention, however, has been paid to morphological characteristics of CaCO 3 in carbonated cement concrete. Signicant diversity in the microstructure and morphology of CaCO 3 crystals in carbonated CBMs has been reported.…”

Section: Introductionmentioning

confidence: 99%

Morphological characteristics of calcium carbonate crystallization in CO₂ pre-cured aerated concrete

Ruan

Liu

et al. 2022

RSC Adv.

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“…Although it has been reported that proper heat-treatment process and controlling the content of alkali metal ions in the colloid can improve service performances of the silicate adhesive under the humid working conditions, the specific optimization parameters and the impacts on the insulation and bonding properties of the colloid have not been deeply studied. It limits the application of adhesive in relevant fields [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Degradation behavior of heat-treatment silicate adhesive under special working conditions

Zhao¹,

Fan²,

Cui³

et al. 2022

J. Phys.: Conf. Ser.

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Inorganic adhesive is widely used in the sealing and connection of electronic devices. Its insulation is highly important in the performance of installation. In this paper, the insulation resistance and tensile strength of different composite silicate samples were measured by test machines. The morphology and surface composition were analyzed by electronic microscope and energy spectrum analyzer. The results show that: In a humid environment, the resistance insulation of adhesive increases with the rising of heat treatment temperature, and decreases with the increment of wet environment. When the modulus ratio of colloidal liquid is in the range of 7.2~9.1 and the heat-treatment temperature is larger than 600°C, the effect of moisture resistant is remarkable. The tensile strength of adhesive deteriorates with the increasing of humidity. Furthermore, with ascending heat treatment temperature, the tensile strength rises when the modulus ratio of adhesive is less than 7.2, and declines when it is more than 9.1.

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Effect of water-to-cement ratio induced hydration on the accelerated carbonation of cement pastes

Cited by 65 publications

References 53 publications

High Temperature Degradation Mechanism of Concrete with Plastering Layer

High Temperature Degradation Mechanism of Concrete with Plastering Layer

Morphological characteristics of calcium carbonate crystallization in CO₂ pre-cured aerated concrete

Degradation behavior of heat-treatment silicate adhesive under special working conditions

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Effect of water-to-cement ratio induced hydration on the accelerated carbonation of cement pastes

Cited by 65 publications

References 53 publications

High Temperature Degradation Mechanism of Concrete with Plastering Layer

High Temperature Degradation Mechanism of Concrete with Plastering Layer

Morphological characteristics of calcium carbonate crystallization in CO2 pre-cured aerated concrete

Degradation behavior of heat-treatment silicate adhesive under special working conditions

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Product

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Morphological characteristics of calcium carbonate crystallization in CO₂ pre-cured aerated concrete