Chloride binding related to hydration products

Florea, M.V.A.; Brouwers, Hjh Jos

doi:10.1016/j.cemconres.2011.09.016

Cited by 321 publications

(118 citation statements)

References 33 publications

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“…When chlorides penetrate cement based structures, some are either bound physically by the calcium silicate hydrate (CSH) phase or chemically by the alumina-ferric oxide-monosulphate (AFm) phase, while some remain as free chlorides in the pore solution. The free chlorides in pore solution cause depassivation of rebar [8]. They also lower the pH of the mortar/concrete surrounding the embedded steel reinforcement, leading to pitting corrosion.…”

Section: Introductionmentioning

confidence: 99%

Chloride Ingress in Chemically Activated Calcined Clay-Based Cement

Marangu

Thiong’o

Wachira

2018

Journal of Chemistry

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Chloride-laden environments pose serious durability concerns in cement based materials. This paper presents the findings of chloride ingress in chemically activated calcined Clay-Ordinary Portland Cement blended mortars. Results are also presented for compressive strength development and porosity tests. Sampled clays were incinerated at a temperature of 800 ∘ C for 4 hours. The resultant calcined clay was blended with Ordinary Portland Cement (OPC) at replacement level of 35% by mass of OPC to make test cement labeled PCC35. Mortar prisms measuring 40 mm × 40 mm × 160 mm were cast using PCC35 with 0.5 M Na 2 SO 4 solution as a chemical activator instead of water. Compressive strength was determined at 28th day of curing. As a control, OPC, Portland Pozzolana Cement (PPC), and PCC35 were similarly investigated without use of activator. After the 28th day of curing, mortar specimens were subjected to accelerated chloride ingress, porosity, compressive strength tests, and chloride profiling. Subsequently, apparent diffusion coefficients ( app ) were estimated from solutions to Fick's second law of diffusion. Compressive strength increased after exposure to the chloride rich media in all cement categories. Chemically activated PCC35 exhibited higher compressive strength compared to nonactivated PCC35. However, chemically activated PCC35 had the least gain in compressive strength, lower porosity, and lower chloride ingress in terms of app , compared to OPC, PPC, and nonactivated PCC35.

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Section: Introductionmentioning

confidence: 99%

Chloride Ingress in Chemically Activated Calcined Clay-Based Cement

Marangu

Thiong’o

Wachira

2018

Journal of Chemistry

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“…The source of chlorides in this study is considered to be NaCl, as explained in [1]. The typical concentration of NaCl in seawater is fairly constant, ranging between 0.6 and 0.7 mol Cl À /l (M) seawater.…”

Section: Introductionmentioning

confidence: 99%

“…The chloride ions, responsible for the initiation of the corrosion mechanism, intrude from the external medium into the concrete. A part of the intruding chloride ions will be retained by the hydration products of the binder in concrete, either through chemical binding or by physical adsorption [1]. These retained chloride ions are generically referred to as ''bound chlorides''.…”

Section: Introductionmentioning

confidence: 99%

Modelling of chloride binding related to hydration products in slag-blended cements

Florea

Brouwers

2014

Construction and Building Materials

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h i g h l i g h t sThe composition of the slag is crucial to the chloride binding capacity of a paste. The interaction between the slag and OPC components is taken into account. The C-S-A-H phase binds approximately two thirds of the total bound chlorides. The remaining third is attributed to AFm phases. The results of the model are highly improved from a previous model from literature. a r t i c l e i n f o a b s t r a c tAn improved hydration model of slag-blended cements, taking into account new insights, is used to estimate and quantify the hydration products of slag-blended cements. Individual chloride binding isotherms are used to correlate these amounts of hydration products with the amount of bound chlorides. A number of parameters are directly or indirectly taken into account when estimating the chloride binding ability of a slag-blended cement paste: cement composition, slag content, water/binder ratio, curing age, and free chloride concentration. The model allows the study of the breakdown of bound chlorides by hydration products and their source -either the OPC or the slag.

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“…In the hardened cement paste two main chloride binding mechanisms are considered (i) through physical adsorption and (ii) through chemical reactions [11]. The CSH phase is considered to physically bind chlorides due to its high specific surface values [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Concrete with Improved Chloride Binding and Chloride Resistivity by Blended Cements

Kopecskó

Balázs

2017

Advances in Materials Science and Engineering

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Durability and service life of concrete structures can be endangered by chloride ions. Two phenomena help to keep control of chloride effects. On one hand cements are able to bind chloride ions by their aluminate clinker phases or by the clinker substituting materials. On the other hand resistivity of concrete against chloride penetration can be improved by careful selection of concrete constituents and production. Detailed results of two series of extensive experimental studies are presented herein. Chloride ion binding capacity of tested cements in decreasing sequence was the following:

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Chloride binding related to hydration products

Cited by 321 publications

References 33 publications

Chloride Ingress in Chemically Activated Calcined Clay-Based Cement

Chloride Ingress in Chemically Activated Calcined Clay-Based Cement

Modelling of chloride binding related to hydration products in slag-blended cements

Concrete with Improved Chloride Binding and Chloride Resistivity by Blended Cements

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