Diffusivity of saturated ordinary Portland cement-based materials: A critical review of experimental and analytical modelling approaches

Patel, Ravi A.; Phung, Quoc Tri; Seetharam, S. C.; Perko, Janez; Jacques, Diederik; Maes, N.; Schutter, Geert De; Ye, Guang

doi:10.1016/j.cemconres.2016.09.015

Cited by 131 publications

(55 citation statements)

References 117 publications

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“…It is therefore apparent that the high porosity in OPC-H 2 O provided the pathway for the ingress of chlorides in mortar. Moreover, blended cements have higher binding capacity as a result of incorporated pozzolana materials and increased hydration products [18,19]. Hydrated blended cement has been reported to contain higher content of CSH content than hydrated OPC-H 2 O [30].…”

Section: Chloride Ingressmentioning

confidence: 99%

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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: Chloride Ingressmentioning

confidence: 99%

“…The most common present practice to measure the amount of chlorides versus penetration depth is to use chloride profile after a predetermined time of exposure [2,14,[17][18][19]. The fitting of this profile to the error function equation enabled the calculation of the diffusion coefficient, mig .…”

Section: Chloride Profilingmentioning

confidence: 99%

Chloride Ingress in Chemically Activated Calcined Clay-Based Cement

Marangu

Thiong’o

Wachira

2018

Journal of Chemistry

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“…Such a mode of (physically reasonable) upscaling has been repeatedly described in the open literature, see, e.g., (Hashin 1968;Dormieux and Lemarchand 2001;Boutin andGeindreau 2010 andPatel et al 2016). Thus, we would qualify our approach as a typical "micromechanics strategy."…”

Section: Discussionmentioning

confidence: 99%

Self-Consistent Channel Approach for Upscaling Chloride Diffusivity in Cement Pastes

et al. 2017

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Chloride ingress into concrete is a major cause for material degradation, such as cracking due to corrosion-induced steel reinforcement expansion. Corresponding transport processes encompass diffusion, convection, and migration, and their mathematical quantification as a function of the concrete composition remains an unrevealed enigma. Approaching the problem step by step, we here concentrate on the diffusivity of cement paste, and how it follows from the microstructural features of the material and from the chloride diffusivity in the capillary pore spaces. For this purpose, we employ advanced self-consistent homogenization theory as recently used for permeability upscaling, based on the resolution of the pore space as pore channels being oriented in all space directions, resulting in a quite compact analytical relation between porosity, pore diffusivity, and the overall diffusivity of the cement paste. This relation is supported by experiments and reconfirms the pivotal role that layered water most probably plays for the reduction of the pore diffusivity, with respect to the diffusivity found under the chemical condition of a bulk solution.Keywords Diffusion · Homogenization · Chlorides · Multiscale modeling · Layered water List of Symbols Mathematical operators divDivergence operator, applied to a vector field div Divergence operator, applied to a second-order tensor field grad Gradient operator on the microscopic observation scale of pore space

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“…Tortuosity is often linked to porosity using Archie's law or the model of Millington and Quirk (1961). For cement systems, some models discriminate between the types of porosity (gel versus capillary porosity) and associated cement phases (Patel et al, 2016). The heat capacity can be linked to individual heat capacities of the minerals in the system.…”

Section: Flow-transport-geochemistry Interactionsmentioning

confidence: 99%

The HPx software for multicomponent reactive transport during variably-saturated flow: Recent developments and applications

Jacques

Šimůnek

Mallants

et al. 2018

Journal of Hydrology and Hydromechanics

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HPx is a multicomponent reactive transport model which uses HYDRUS as the flow and transport solver and PHREEQC-3 as the biogeochemical solver. Some recent adaptations have significantly increased the flexibility of the software for different environmental and engineering applications. This paper gives an overview of the most significant changes of HPx, such as coupling transport properties to geochemical state variables, gas diffusion, and transport in two and three dimensions. OpenMP allows for parallel computing using shared memory. Enhancements for scripting may eventually simplify input definitions and create possibilities for defining templates for generic (sub)problems. We included a discussion of root solute uptake and colloid-affected solute transport to show that most or all of the comprehensive features of HYDRUS can be extended with geochemical information. Finally, an example is used to demonstrate how HPx, and similar reactive transport models, can be helpful in implementing different factors relevant for soil organic matter dynamics in soils. HPx offers a unique framework to couple spatial-temporal variations in water contents, temperatures, and water fluxes, with dissolved organic matter and CO 2 transport, as well as bioturbation processes.

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Diffusivity of saturated ordinary Portland cement-based materials: A critical review of experimental and analytical modelling approaches

Cited by 131 publications

References 117 publications

Chloride Ingress in Chemically Activated Calcined Clay-Based Cement

Chloride Ingress in Chemically Activated Calcined Clay-Based Cement

Self-Consistent Channel Approach for Upscaling Chloride Diffusivity in Cement Pastes

The HPx software for multicomponent reactive transport during variably-saturated flow: Recent developments and applications

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