Effectiveness of surface coatings in concrete: chloride penetration and carbonation

Carneiro, Ana Flávia Baú; Daschevi, P. A.; Langaro, Eloise Aparecida; Pieralisi, Ricardo; Medeiros, Marcelo Henrique Farias de

doi:10.1007/s41024-020-00098-8

Cited by 10 publications

(8 citation statements)

References 15 publications

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“…Since less CH is present in the EnM-06, the carbonation front was found further from the top surface; for example, after 90 days of carbonation it was found ~12 mm from the surface, while in RefM-06 it was found at ~8 mm. A similar occurrence was observed by Carneiro et al [ 28 ], who used specimens with low and high Portland cement content and found the carbonation front significantly deeper in specimens with low cement content. The depth of carbonation front measured with TGA corresponds well to the carbonation depth measured with the visual method and, therefore, with the results previously shown in Figure 4 .…”

Section: Resultssupporting

confidence: 86%

Experimental Carbonation Study for a Durability Assessment of Novel Cementitious Materials

et al. 2021

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Durability predictions of concrete structures are derived from experience-based requirements and descriptive exposure classes. To support durability predictions, a numerical model related to the carbonation resistance of concrete was developed. The model couples the rate of carbonation with the drying rate. This paper presents the accelerated carbonation and moisture transport experiments performed to calibrate and verify the numerical model. They were conducted on mortars with a water-cement ratio of either 0.6 or 0.5, incorporating either a novel cement CEM II/C (S-LL) (EnM group) or commercially available CEM II/A-S cement (RefM group). The carbonation rate was determined by visual assessment and thermogravimetric analysis (TGA). Moisture transport experiments, consisting of drying and resaturation, utilized the gravimetric method. Higher carbonation rates expressed in mm/day−0.5 were found in the EnM group than in the RefM group. However, the TGA showed that the initial portlandite (CH) content was lower in the EnM than in the RefM, which could explain the difference in carbonation rates. The resaturation experiments indicate an increase in the suction porosity in the carbonated specimens compared to the non-carbonated specimens. The study concludes that low clinker content causes lower resistance to carbonation, since less CH is available in the surface layers; thus, the carbonation front progresses more rapidly towards the core.

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Section: Resultssupporting

confidence: 86%

Experimental Carbonation Study for a Durability Assessment of Novel Cementitious Materials

et al. 2021

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“…Protective coatings of the concrete surface against aggressive environments are constantly evolving. Given their diversity, the effectiveness of the latter becomes an important criterion for making the right among of a large, commercialized variety, therefore, in recent years, several researchers [23,29,30,31] have started research in this area and have proposed solutions to protect the surface exterior of concrete with coatings, such as organic, inorganic, mortars and paints against environmental aggressions. Among these aggressions, comes first the concrete carbonation, which is a natural phenomenon which compromises the durability of reinforced concrete structures by causing the corrosion of the reinforcements.…”

Section: Use Of Protective Coatingsmentioning

confidence: 99%

“…al. [31], in their study aimed to evaluate the efficiency of certain surface treatments (such as polyurethane coating, hydrophobic agents and cementitious crystalline) applied on concrete under chloride ions and carbon dioxide exposure. The results indicated that polyurethane coating is efficient against the ingress of aggressive agents.…”

Section: Use Of Anti-carbonation Coatingsmentioning

confidence: 99%

Prevention of Carbonation of RC Structures (Critical Review)

2022

International Journal of Advances in Structural and Geotechnica

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Carbonation of concrete is traditionally defined as the chemical reaction between atmospheric carbon dioxide and the products of cement hydration, particularly calcium hydroxide. This phenomenon will reduce an alkaline pH of concrete of approximately 12.6, whereas the carbonated concrete is more neutral with a pH value which may decrease to 8.3. The degradation mechanism which threatens the reinforcement is corrosion, but the alkaline environment will safeguard the protective film as the pH of the surrounding solution remains within certain limits. Carbonation is a threat as it lowers pH and so may bring the steel within the corrosion boundary. Thus, carbonation may be a factor in the initiation of corrosion. Carbonation itself does not attack the reinforcement but it may contribute significantly to a lowering of the defense mechanism inherent in the synergetic relationship between steel reinforcement and concrete. This paper presents literature review of different methods which can be used to prevent the carbonation of concrete of existing structures and new one. The prevention methods include the use of protective coatings, anti-carbonation coatings and admixtures. From the literature review, it can be concluded that carbonation of concrete can be eliminated and prevented by using some anti-carbonation coatings. Also, using of protective coatings and/or cement plastering will reduce the carbonation depth. Moreover, concrete quality and good construction practices are governing factors on the rate of carbonation. The treatment of existing carbonated reinforced concrete structures is discussed.

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“…8 Covering the surface of the concrete with a layer of polymer film (polyurethane coating, acrylic coating, polymer coil, asphalt coil) or painting hydrophobic silane molecules (permeation type, surface film-forming type) is what is meant by the term "external coating type". 9,10 The formulation of the concrete does not need to be altered in any way for these procedures to be used, and existing building structures can be directly waterproofed using them. Because the external coating method is only applied on one side, it is required to make an advance prediction of the spots that are likely to have water leakage.…”

Section: Introductionmentioning

confidence: 99%

“…It is possible to divide it into two categories: the external coating type and the internal mixing type 8 . Covering the surface of the concrete with a layer of polymer film (polyurethane coating, acrylic coating, polymer coil, asphalt coil) or painting hydrophobic silane molecules (permeation type, surface film‐forming type) is what is meant by the term “external coating type” 9,10 . The formulation of the concrete does not need to be altered in any way for these procedures to be used, and existing building structures can be directly waterproofed using them.…”

Section: Introductionmentioning

confidence: 99%

A ultra‐low viscosity stearic acid emulsion prepared by lauric acid as waterproof agent for cement mortar

Huang,

Wu,

Wang

et al. 2023

J of Applied Polymer Sci

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Safe building structures cannot be achieved without reliable waterproofing engineering. To address the susceptibility of concrete materials to water leakage, a low‐viscosity stearic acid emulsion has been developed as a waterproofing agent for mortar. By introducing lauric acid, the formation of stearic acid crystals in water could be effectively prevented, resulting in a stearic acid emulsion with a viscosity of only 24 mPa·s. It is found that the best overall performance was achieved when the ratio (R) of lauric acid to stearic acid was 2/3. This emulsion has the least effect on mortar fluidity and setting time. The as‐prepared modified mortar possessed the highest compressive strength (127% of the blank) and the lowest water absorption at 48 h (37% of the blank). X‐ray diffraction (XRD), Fourier‐transform infrared spectroscopy (FTIR), energy‐dispersive x‐ray spectroscopy (EDS), scanning electron microscopy (SEM), dynamic light scattering (DLS) particle size analysis, and water contact angle measurements were used to investigate the mechanism of stearic acid emulsion's modification. It is determined that the stearic acid emulsions successfully modified the internal and external hydrophobicity of the mortar by chemical action with calcium hydroxide.

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Effectiveness of surface coatings in concrete: chloride penetration and carbonation

Cited by 10 publications

References 15 publications

Experimental Carbonation Study for a Durability Assessment of Novel Cementitious Materials

Experimental Carbonation Study for a Durability Assessment of Novel Cementitious Materials

Prevention of Carbonation of RC Structures (Critical Review)

A ultra‐low viscosity stearic acid emulsion prepared by lauric acid as waterproof agent for cement mortar

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