Improvement of concrete carbonation resistance based on a structure modified Layered Double Hydroxides (LDHs): Experiments and mechanism analysis

Shui, Zhong He; Yu, Ruilong; Chen, Y.X.; Duan, Ping; Ma, Jixin; Wang, X.P.

doi:10.1016/j.conbuildmat.2018.04.222

Cited by 41 publications

(16 citation statements)

References 55 publications

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“…They observed a 30% reduction in carbonation depth at 42 day age. Similar findings were also reported by Shui et al [132]. This highlights the positive benefits of employing LDH in carbonation control of structures.…”

Section: Role Of Ldh In Carbonation Controlsupporting

confidence: 90%

“…However, as the ion exchange is based on charge conservation, LDHs are particularly affine to divalent anions as compared to monovalent anions with carbonate anions being the most preferred anion for most of the LDHs. As such, LDHs have been used to increase the carbonation resistance of concrete [132] as they can efficiently capture carbonate ions.…”

Section: Ion Exchange Property and Self Protection Of Concretementioning

confidence: 99%

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Recent Advances on the Application of Layered Double Hydroxides in Concrete—A Review

et al. 2020

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The issue of chloride induced corrosion of reinforced concrete is a serious problem affecting infrastructure globally and causing huge economic losses. As such this issue has gained a considerable attention in the scientific community in the recent past. Layered Double Hydroxides (LDHs) have recently emerged as a new class of concrete-additives with a potential to increase the chloride resistance of concrete and mitigate corrosion. LDHs are clay like structures consisting of positively charged layers of cations with associated hydroxides and exchangeable anions in between the layers. Due to this charge balanced structure, LDHs possess the property of encapsulating an anion from the environment and replacing it with an exchangeable anion present in its layers. Potential applications include chloride entrapment in concrete and delivery of corrosion inhibiting anions. However, many versatile compositions of LDHs can be easily synthesized and their application as cement additives reach far beyond corrosion mitigation in concrete. This review presents a summary of recent advances on the applications of LDH in concrete. An extensive set of recently published literature has been critically reviewed and trends have been identified.

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Section: Role Of Ldh In Carbonation Controlsupporting

confidence: 90%

Section: Ion Exchange Property and Self Protection Of Concretementioning

confidence: 99%

Recent Advances on the Application of Layered Double Hydroxides in Concrete—A Review

et al. 2020

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“…In the above-mentioned studies, the intercalated anions were nitrite (corrosion inhibitor), nitrate, carbonate, and chloride. The most commonly studied LDH is by far MgAl-LDH [20][21][22]24,27,32,35,[37][38][39][41][42][43][44][45][46][47]49,50], followed by CaAl [16][17][18]26,[32][33][34]40], hydrotalcite [23,29,36], and modified hydrotalcite [25,28,31]. ZnAl-LDH is a new composition that has been studied in only two papers [51,52].…”

Section: Introductionmentioning

confidence: 99%

“…The use of LDH to control the cement hydration kinetics has been studied by several groups [18][19][20][21]. However, most of the work with LDH in concrete is dedicated to the mitigation of steel rebars corrosion, either in chloride media [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] or carbonated concrete [32,[41][42][43][44][45][46][47][48]. Many studies have been done in simulated concrete pore solution [35,38,43,46], just a few in mortar [31,43] and only one in concrete [16].…”

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confidence: 99%

Use of ZnAl-Layered Double Hydroxide (LDH) to Extend the Service Life of Reinforced Concrete

et al. 2020

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This work investigated the use of ZnAl-layered double hydroxide (LDH) intercalated with nitrate or nitrite ions for controlling the corrosion of steel in reinforced concrete. The work started by analyzing the stability of the powder in the 1-14 pH range and the capacity for capturing chloride ions in aqueous solutions of different pH. The effect of the ZnAl-LDH on the corrosion of steel was studied in aqueous 0.05 M NaCl solution and in mortars immersed in 3.5% NaCl. It was found that the LDH powders dissolved partially at pH > 12. The LDH was able to capture chloride ions from the external solution, but the process was pH-dependent and stopped at high pH due to the partial dissolution of LDH and the preferential exchange of OHions. These results seemed to imply that ZnAl-LDH would not work in the alkaline environment inside the concrete. Nonetheless, preliminary results with mortars containing ZnAl-LDH showed lower penetration of chloride ions and higher corrosion resistance of the steel rebars. dioxide leads to the carbonation of concrete, which is accompanied by a decrease in pH. When the front of low pH reaches the steel surface, the passivity is lost and uniform corrosion starts. Chloride ions, on the other hand, can disrupt the passive layer even at high pH, if a threshold concentration is surpassed [5]. In these conditions, the corrosion is localized in the form of pitting, crevice, or stress corrosion cracking. The iron corrosion products are more voluminous than steel, which creates expansive stresses, leading to cracking at first and spallation of the concrete cover at the end. After that, steel becomes directly exposed to the atmospheric environment, and corrosion proceeds at a much faster rate.Since the corrosion of steel rebars dramatically limits the service life of reinforced concrete, many forms of corrosion control are being explored [2][3][4]6,7], including the use of stainless steel or galvanized steel rebars, application of epoxy coating on steel rebars, cathodic protection, and addition of corrosion inhibitors to concrete (e.g., calcium nitrite, sodium benzoate, chromates, phosphates, polyphosphates, silicates, polycarboxylic acids, fatty acids emulsions, and alkanolamines). Corrosion can also be delayed by painting the surface of the concrete structure or using a thicker layer of concrete, separating the rebars and the environment. Less porous concrete (lower water/cement ratio), high quality cement, and the use of water and aggregates without soluble salts also contribute to extending the durability of the structure.The direct addition of corrosion inhibitors to concrete may affect the curing process or the mechanical properties of the hardened material. Because of this possibility, the encapsulation of inhibitors in nano-or micro-reservoirs to be released only when needed (either with the onset of corrosion or in the presence of aggressive species) is a line of investigation worth pursuing.Layered double hydroxides (LDHs) are one example of such nanostructured reservoirs. The LDH structure...

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“…Normally, the pH value inside concrete is above 12.5. Under such pH value, a passivation layer (densified Fe 3 O 4 -γFe 2 O 3 film) with a thickness of about 2-10 μm would be formed on the surface of steel reinforcement and prevent corrosion of steel to occur (Shui et al, 2018). During the operation stage of concrete structures, CO 2 in the atmosphere intrudes into concrete and reacts with the lime, resulting in a decrease of alkalinity inside the concrete.…”

Section: Concrete Carbonation Depth Modelmentioning

confidence: 99%

Effect of Concrete Stress States on Carbonation Depth of Concrete

Wang

et al. 2019

Journal of Civil Engineering and Management

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Carbonation can lead to reduction of alkalinity of concrete and initiation of steel reinforcement corrosion. In durability design of concrete structures, the carbonation depth should be duly considered. However, the concrete stress state would influence the carbonation depth, and there has been inadequate research on such effect. In this study, it is proposed to introduce a stress influence coefficient to the concrete carbonation depth model. With reference to the experimental data from eleven research studies in the literature encompassing both tensile and compressive stress states, the relationship between stress influence coefficient and concrete stress ratio is quantitatively investigated, and mathematical equations relating the stress influence coefficient with the concrete stress ratio are established. Comparative study with three typical existing groups of equations shows that the proposed equations of stress influence coefficient are more reasonable and have a higher reliability. The effects of carbonation time, mix proportions of concrete on stress influence coefficient are also analysed, and the magnitudes of the effects are found to be approximately within ±10%. Finally, the modified carbonation depth models are proposed and verified by the experimental data, which suggests that the proposed models are of desirable accuracy. Adoption of the proposed equations as the modified formula of stress influence coefficient in the concrete carbonation depth model for practical applications is recommended.

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Improvement of concrete carbonation resistance based on a structure modified Layered Double Hydroxides (LDHs): Experiments and mechanism analysis

Cited by 41 publications

References 55 publications

Recent Advances on the Application of Layered Double Hydroxides in Concrete—A Review

Recent Advances on the Application of Layered Double Hydroxides in Concrete—A Review

Use of ZnAl-Layered Double Hydroxide (LDH) to Extend the Service Life of Reinforced Concrete

Effect of Concrete Stress States on Carbonation Depth of Concrete

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