Bound chloride ingress in alkali activated concrete

Mangat, P. S.; Ojedokun, Olalekan O.

doi:10.1016/j.conbuildmat.2019.03.302

Cited by 25 publications

(14 citation statements)

References 18 publications

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“…It is also observed that the chloride binding capacity which regulates the amount of free chloride available to support corrosion is lower in AACM than PC concrete [23]. Hence, a higher amount of free chloride is released in the pore matrix of AACM concrete.…”

Section: Resultsmentioning

confidence: 98%

“…Hence, a higher amount of free chloride is released in the pore matrix of AACM concrete. The higher chloride binding capacity (acid and water soluble) of PC concrete [23] is due to the significant presence of hydrotalcite and Friedel's salts (Fig. 7b).…”

Section: Resultsmentioning

confidence: 99%

“…Phases such as hydrotalcite provide surface absorption to physically bind chloride and are sensitive to changes in pH, chloride concentration and total ionic strength [36]. The C 3 A content in PC concrete produces Ca 6 Al 2 O 6 .CaCl 2 .10H 2 O (Friedel's salt) which accounts for its high chloride binding capacity [23]. The presence of gypsum in AACM concrete increases solubility of ions leading to the release of sulfate ions into its pore solution [15].…”

Section: Resultsmentioning

confidence: 99%

“…The activator used in the AACM concrete is a sodium silicate solution of 6.5mol/L molarity and 2% modulus, together with NaOH of molarity 4.8mol/L. AACM 1, 2 and 3 mixes were produced by diluting the activator with water at 0%, 3.88% and 7.76% respectively as shown in Table 1, to produce low, medium and high strength grades [16,23]. A liquid-binder ratio of 0.47, 10mm uncrushed gravel, 6mm limestone and a medium grade sand with 80% particle size passing 1mm sieve were used in both the AACM and PC concrete mixes.…”

Section: Materials and Mixesmentioning

confidence: 99%

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Chloride-initiated corrosion in alkali activated reinforced concrete

Mangat

Ojedokun

Lambert

2021

Cement and Concrete Composites

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The use of ordinary Portland cement (PC) as the principal binder in concrete brings with it significant environmental challenges through the consumption of fossil fuels and emission of carbon dioxide (CO 2 ) during cement production. Concrete specimens made with an alkali activated cementitious material (AACM) produced from an alternative binder and conventional Portland cement concrete were exposed to corrosion inducing environments for 1 750 days to monitor their relative durability. AACM concrete shows higher corrosion potential E corr and corrosion current densities I corr than PC concrete due to a reducing environment around the steel surface in AACM concrete, caused by high sulfide concentration in the pore solution.Corrosion resistance of the AACM concretes increases with increasing molarity of the alkali activator, at a constant liquid to binder ratio. The threshold Cl -/OHvalue for pitting corrosion initiation in the AACM concrete is between 2.1 and 2.8 compared with 1.08 for the control PC concrete. The AACM concrete evaluated in this study showed greater resistance to chloride induced corrosion than the PC concrete.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Materials and Mixesmentioning

confidence: 99%

See 2 more Smart Citations

Chloride-initiated corrosion in alkali activated reinforced concrete

Mangat

Ojedokun

Lambert

2021

Cement and Concrete Composites

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“…Sulfate attack on concrete can manifest as expansion or cracking, leading to increased concrete permeability, structural problems and initiating corrosion processes of reinforcement (Mehta and Monteiro, 2014). According Mangat and Ojedokun (2019) the chloride concentration of concrete exposed to a chloride environment is a parameter used to characterize the long term chloride resistance of concrete. The presence of chlorides is a cause of the corrosion process in reinforcement of reinforced concrete structures.…”

Section: Introductionmentioning

confidence: 99%

Behavior of Mortars with Different Porosities in Front of Attack of Aggressive Agents

Weber¹,

Mazer²,

Pedroso³

et al. 2020

XV International Conference on Durability of Building Materials and Components. eBook of Proceedings

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Chemical reactions that lead to decreased durability in concrete structures may result from chemical interactions between aggressive agents present in the external environment and cement paste compounds or may result from internal reactions. The chemical reactions are manifested by the physical properties of the concrete, such as porosity and permeability and the decrease of resistance and cracking. Among the several aggressive agents that attack the reinforced concrete structures it can be highlighted chloride ions, sulphate ions and carbon dioxide. In this context, the study presents the analysis of different traces of mortar executed with cement type CPII-F-32 (OPC Cement, in Brazil one of the most used cements) with w/c ratios of 0.4 and 0.7, when subjected to the attack of sulphates, chlorides and carbonation. The analyzes quantitatively evaluated the amount of ions present after exposure to the agents and demonstrate the importance of evaluating the dosage of water in the mortars to minimize future problems with durability.

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Effect of chloride salt on the phase evolution in alkali-activated slag cements through thermodynamic modelling

Zuo

2022

Applied Geochemistry

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Bound chloride ingress in alkali activated concrete

Cited by 25 publications

References 18 publications

Chloride-initiated corrosion in alkali activated reinforced concrete

Chloride-initiated corrosion in alkali activated reinforced concrete

Behavior of Mortars with Different Porosities in Front of Attack of Aggressive Agents

Effect of chloride salt on the phase evolution in alkali-activated slag cements through thermodynamic modelling

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