A model for reactive porous transport during re-wetting of hardened concrete

Chapwanya, Michael; Liu, Wentao

doi:10.1007/s10665-009-9268-0

Cited by 11 publications

(6 citation statements)

References 38 publications

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“…with D(w, ε) is water diffusivity and depends on both the moisture content and porosity (in general, we have that 0 ≤ w ≤ ε). A possible choice for diffusivity is Chapwanya et al (2009):…”

Section: Water Movementmentioning

confidence: 99%

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A forecasting model for the porosity variation during the carbonation process

et al. 2022

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In this paper we introduce a mathematical model of concrete carbonation Portland cement specimens. The main novelty of this work is to describe the intermediate chemical reactions, occurring in the carbonation process of concrete, involving the interplay of carbon dioxide with the water present into the pores. Indeed, the model here proposed, besides describing transport and diffusion processes inside the porous medium, takes into account both fast and slow phenomena as intermediate reactions of the carbonation process. As a model validation, by using the mathematical based simulation algorithm we are able to describe the effects of the interaction between concrete and CO$$_2$$ 2 on the porosity of material as shown by the numerical results in substantial accordance with experimental results of accelerated carbonation taken from literature. We also considered a further reaction: the dissolution of calcium carbonate under an acid environment. As a result, a trend inversion in the evolution of porosity can be observed for long exposure times. Such an increase in porosity results in the accessibility of solutions and pollutants within the concrete leading to an higher permeability and diffusivity thus significantly affecting its durability.

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Section: Water Movementmentioning

confidence: 99%

“…with A and B shape parameters for water diffusivity, suitable constants taken from Chapwanya et al (2009) and reported in Table 2.…”

Section: Water Movementmentioning

confidence: 99%

A forecasting model for the porosity variation during the carbonation process

et al. 2022

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“…to describe the deviated water absorption [158,[163][164][165], but more information is needed on the kinetics of internal swelling and time-dependent transport properties of water in CBMs.…”

Section: Deviation From the Srt Lawmentioning

confidence: 99%

“…Physical swelling of C‐S‐H gels and evolving pore structure necessitate time‐dependent water transport properties. Several physical models have been proposed to describe the deviated water absorption, 158,163–165 but more information is needed on the kinetics of internal swelling and time‐dependent transport properties of water in CBMs.…”

Section: Detailed Connotations Of Water Sensitivitymentioning

confidence: 99%

Water sensitivity of cement‐based materials

Zhang

Wang

et al. 2021

J Am Ceram Soc

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Cement-based materials are the most widely used construction materials on the planet. Cementbased materials play a fundamental role in modern civilization and will for the foreseeable future.Although great efforts have been devoted to discovering the behaviors and optimizing their performances, several long-standing controversies persist for the fundamental water-related properties of cement-based materials, which hinder theoretical researches and mislead technological developments. Inspired by the decreasing water permeability of clay-bearing rocks, the term "water sensitivity" in geophysics is borrowed and proposed for cement-based materials. The lamellar structure of negatively charged nanoparticles is responsible for swelling in clay-based reservoir rocks. Amorphous calcium silicate hydrate gels in cement-based materials have similar microstructural characteristics. They probably swell upon wetting and contract upon drying, making the pore structure of cement-based materials dependent on water content. More importantly, several unexplained behaviors of cement-based materials can be rationalized using water sensitivity.Thorough exploration of both the micro-structural characteristics and performances validate the use of water sensitivity for cement-based materials. Because water participates in or regulates almost all physical and chemical processes of cement-based materials, water sensitivity can be a part of the interpretations of almost all of their properties and performances.

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“…In the literature, few studies have reported infiltration tests in concrete. One of the studies was reported by Chapwanya et al (2009), who modelled re-wetting experiments in concrete. They consist of placing dry concrete samples in a liquid bath and observing the progress of the wetting front.…”

Section: Introductionmentioning

confidence: 99%

Reactive transport modelling of a high-pH infiltration test in concrete

Chaparro

Soler

Saaltink

et al. 2017

Physics and Chemistry of the Earth, Parts A/B/C

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A laboratory-scale tracer test was carried out to characterize the transport properties of concrete from the Radioactive Waste Disposal Facility at El Cabril (Spain). A hyperalkaline solution (K-Ca-OH, pH = 13.2) was injected into a concrete sample under a high entry pressure in order to perform the experiment within a reasonable time span, obtaining a decrease of permeability by a factor of 1000. The concentrations of the tracers, major elements (Ca2+, SO42-, K+ and Na+) and pH were measured at the outlet of the concrete sample. A reactive transport model was built based on a double porosity conceptual model, which considers diffusion between a mobile zone, where water can flow, and an immobile zone without any advective transport. The numerical model assumed that all reactions took place in the immobile zone. The cement paste consists of C-S-H gel, portlandite, ettringite, calcite and gypsum, together with residual alite and belite. Two different models were compared, one with portlandite in equilibrium (high initial surface area) and another one with portlandite reaction controlled by kinetics (low initial surface area). Overall the results show dissolution of alite, belite, gypsum, quartz, C-S-H gel and ettringite and precipitation of portlandite and calcite. Permeability could have decreased due to mineral precipitation.Peer ReviewedPostprint (author's final draft

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A model for reactive porous transport during re-wetting of hardened concrete

Cited by 11 publications

References 38 publications

A forecasting model for the porosity variation during the carbonation process

A forecasting model for the porosity variation during the carbonation process

Water sensitivity of cement‐based materials

Reactive transport modelling of a high-pH infiltration test in concrete

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