Influence of crack width on the stiffness recovery and self-healing of reactive magnesia-based binders under CO2-H2O conditioning

Ruan, Shaoqin; Qiu, Jishen; Yang, En-Hua; Unluer, Cise

doi:10.1016/j.conbuildmat.2020.121360

Cited by 13 publications

(5 citation statements)

References 69 publications

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“…3a shows the carbonation frontier of RMC with different contents of sisal fiber after 28-day curing. The phenolphthalein turns pink in the presence of OH -(e.g., pH > 10), hence no change in color indicates the OHwas consumed by HCO3derived from the dissolution of CO2 [19]. As it can be seen, almost all the exposed surfaces of control group RMC_Sisal (0%) are pink, suggesting a negligible carbonation depth, this coincides with the slowest development rate of mechanical strength as shown in Fig.…”

Section: Carbonation Depth and Degreementioning

confidence: 71%

“…After compressive tests, the cubes were cut off in the middle, and the phenolphthalein, which would change to pink if pH>10 [19], was sprayed onto the newly exposed surface as an indicator of carbonation depth. To increase the accuracy, the average depth of the carbonation region was perpendicularly measured from four midpoints of four edges.…”

Section: Carbonation Detectionmentioning

confidence: 99%

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High-performance Reactive Magnesium Cement Incorporating Hollow Natural Fiber and Silica Sand

Qiu

2022

MATEC Web Conf.

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Global warming caused by CO2 emissions makes reactive magnesium cement (RMC) increasingly attractive due to its ability to sequester CO2, however, the diffusion of CO2 in RMC is severely limited by the dense hydrated magnesium carbonates (HMCs) formed on the outer layer. This work utilizes hollow natural fiber (e.g., sisal fiber) to facilitate the diffusion of CO2 into the deep part of the RMC specimen. Combining with adding silica sand as a filling agent, the mechanical strength can be enhanced from 42.4 MPa of the control group to 92.6 MPa of the specimen with 2 vol.% sisal fiber, this is attributed to that the addition of sisal fiber significantly enhances the carbonation depth. FTIR and XPS results further prove that the addition of 2 vol.% or more sisal fiber can improve the carbonation degree by over 200%, leading to a sharp reduction of CO2 emission from 37 kg/(m3>MPa) of the control group to 12.1 kg/(m3∘MPa) of the specimen with 2 vol.% sisal fiber. Therefore, adding hollow natural fiber and silica sand to RMC can be a promising approach to make RMC stronger and more sustainable.

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Section: Carbonation Depth and Degreementioning

confidence: 71%

Section: Carbonation Detectionmentioning

confidence: 99%

High-performance Reactive Magnesium Cement Incorporating Hollow Natural Fiber and Silica Sand

Qiu

2022

MATEC Web Conf.

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“…It is also worth noting that 3C–M and C–M show larger peaks around 1 μm compared to MH and 3C–M. This may be explained by the formation of MgCO 3 ·3H 2 O with a lower density (1.85 g/cm 3 ) in MH and 3C–M, causing a higher volume increase and reduced micropores. , …”

Section: Resultsmentioning

confidence: 91%

Elucidating the Interaction Mechanism of Mg(OH)₂ and Ca(OH)₂ under Enforced Carbonation

Zhang

Liu

Wang

et al. 2023

ACS Sustainable Chem. Eng.

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There is a potential for leveraging the synergy of carbonation of portlandite and Mg-based binders to improve the CO 2 uptake, mechanical property, and thermodynamic stability of Mg-and Ca-based binders and enable its application. This work reports insights into the carbonation behavior of Mg(OH) 2 −Ca(OH) 2 (MH−CH) mixtures including the precipitation of different carbonates, degree of reaction of each phase, mechanical properties, microstructure characterization, and thermodynamic stability. Results indicate that the compressive strength and degree of carbonation (DOC) of compacts increase first and then decrease with the increase of the Ca(OH) 2 content. The compact containing 25% Ca(OH) 2 yields the highest compressive strength of 91.4 MPa, while the compact containing 75% Ca(OH) 2 has the highest DOC of 91.2%. The formation of nesquehonite with a lower density in compacts with lower contents of Ca(OH) 2 (0 and 25%) results in a higher volume increase even at a very low DOC (14.2%), leading to a more densified structure in the compacts. Compacts with higher contents of Ca(OH) 2 (50, 75, and 100%) precipitate calcite and magnesium calcite with higher thermodynamic stability than nesquehonite and improved water stability. Meanwhile, the high temperature in the initial stage of Ca(OH) 2 carbonation causes severe water evaporation and insufficient water in compacts, thus restricting the continuous carbonation at the center having a lower DOC than the surface. The mixing of Mg(OH) 2 and Ca(OH) 2 significantly enhances the carbonation degree of both hydroxides, which may be explained by the complementation of Ca(OH) 2 and Mg(OH) 2 carbonation, in which the water released by the carbonation of Ca(OH) 2 is bound to the crystal structure of hydrated magnesium carbonates (HMCs) from Mg(OH) 2 carbonation.

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“…4. It should be noted that the damage level is usually quantified by the crack width [48,49,60], crack length [59] or crack density [61]. Hence, in this figure, different damage indices are unified as the damage level for a direct and qualitative comparison.…”

Section: Overview Of Characteristics In Intrinsic Healing Processesmentioning

confidence: 99%

“…Please note that the legend is valid for both plots. Figure 4: Eect of damage level on the healing capability of dierent materials such as bituminous binders [48] and berreinforced concrete [49], asphalt mastic [59], mortar [60], concrete [61]. Some authors provide slightly dierent thresholds to set up a damage level, which are sometimes dened at the peak stress level or at certain point during the post-peak stress-strain stage.…”

Section: Overview Of Characteristics In Intrinsic Healing Processesmentioning

confidence: 99%

A multi-material-oriented modeling framework to characterize and predict mechanical self-healing

Dai

Zhu

Gilabert

2023

International Journal of Mechanical Sciences

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Influence of crack width on the stiffness recovery and self-healing of reactive magnesia-based binders under CO2-H2O conditioning

Cited by 13 publications

References 69 publications

High-performance Reactive Magnesium Cement Incorporating Hollow Natural Fiber and Silica Sand

High-performance Reactive Magnesium Cement Incorporating Hollow Natural Fiber and Silica Sand

Elucidating the Interaction Mechanism of Mg(OH)₂ and Ca(OH)₂ under Enforced Carbonation

A multi-material-oriented modeling framework to characterize and predict mechanical self-healing

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Influence of crack width on the stiffness recovery and self-healing of reactive magnesia-based binders under CO2-H2O conditioning

Cited by 13 publications

References 69 publications

High-performance Reactive Magnesium Cement Incorporating Hollow Natural Fiber and Silica Sand

High-performance Reactive Magnesium Cement Incorporating Hollow Natural Fiber and Silica Sand

Elucidating the Interaction Mechanism of Mg(OH)2 and Ca(OH)2 under Enforced Carbonation

A multi-material-oriented modeling framework to characterize and predict mechanical self-healing

Contact Info

Product

Resources

About

Elucidating the Interaction Mechanism of Mg(OH)₂ and Ca(OH)₂ under Enforced Carbonation