Water permeability of unsaturated cementitious materials: A review

Crystalline hydrophilic additives are increasingly used as efficient methods for reducing water permeability in concrete. Their effectiveness in hindering water penetration has been proven in different cementitious materials, although scarce information has been reported concerning their action mechanism. In the present work, the efficacy of a hydrophilic blended crystalline mix (Krystaline Add1) as a water-reducing additive has been confirmed. Furthermore, an extended study about how the presence of the additive influences both the fresh state and the hardened state properties is presented. Finally, characterization techniques such as Mercury Intrusion Porosimetry (MIP), X-ray Powder Diffraction (XRD) and Back-Scattered Scanning Electron Microscopy (BSEM) with Energy Dispersive X-ray analysis (EDAX) have been used for deducing the mechanism of the additive. No significant deleterious influence on the concrete properties due to the addition of the additive has been detected. In fact, the additive seems to have provided a positive influence on the concrete given that a slight reduction in the w/c ratio for similar consistency has been detected, with the subsequent improvement of the compressive strength values. Its effectiveness as a water permeability reducing additive has shown encouraging results having reduced the water permeability by approximately 50% during testing. The action mechanism of the studied additive seems to be related to hydration reactions in the presence of water, producing new solid amorphous phases in the concrete bulk.

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Simple Modeling to Estimate Water Permeability Coefficient of Cementitious Materials

Journal of the Korea Concrete Institute ◽

10.4334/jkci.2019.31.2.165 ◽

2019 ◽

Vol 31 (2) ◽

pp. 165-172

Author(s):

In-Seok Yoon

Keyword(s):

Water Permeability ◽

Permeability Coefficient ◽

Cementitious Materials ◽

Water Permeability Coefficient ◽

Simple Modeling

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Relationship between Water-Permeability Coefficient and Pore-Structure Indicators of Cementitious Materials

10.20944/preprints201812.0073.v1 ◽

2018 ◽

Author(s):

Yuya Sakai

Keyword(s):

Pore Structure ◽

Water Permeability ◽

Total Pore Volume ◽

Cementitious Materials ◽

Critical Threshold ◽

Determination Coefficient ◽

Water Permeability Coefficient ◽

The Relationship ◽

Very High ◽

Median Pore

To understand the relationship between water permeability and the pore structure of cementitious materials, literature that studied both water permeability and the pore structure are reviewed, and their correlation is studied. Although the majority of this data is for cement paste, mortar, concrete, and cemented soil are also included. Based on this study, it is established the determination coefficient between water permeability and the total pore volume is very low; however, those between water permeability and the critical, threshold, and median pore diameters, respectively, are moderate. On the other hand, the threshold pore diameter, derived based on the percolation theory, exhibits a very high determination coefficient. The calculated water permeability, using the Katz and Thompson equation, agrees with the reported water permeability quantitatively to a certain level, but is overestimated.

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Influence of Water-Repellent Treatment with Silicon Resin on Properties of Concrete

Advances in Materials Science and Engineering ◽

10.1155/2019/5743636 ◽

2019 ◽

Vol 2019 ◽

pp. 1-12 ◽

Cited By ~ 1

Author(s):

Yupeng Tian ◽

Penggang Wang ◽

Tiejun Zhao ◽

Zhiming Ma ◽

Zuquan Jin ◽

...

Keyword(s):

Surface Water ◽

Water Permeability ◽

Effective Means ◽

Cementitious Materials ◽

Water Repellent ◽

Hydration Reaction ◽

Concrete Durability ◽

Durability Properties ◽

Cement Based Materials ◽

Silicon Resin

Although studies on water-repellent properties of silicon resin (SR) on cement-based materials have received tremendous attention around the world in recent years, they mainly focus on individual properties of water-repellent concrete treated with SR such as strength and water permeability resistance. However, to date, a systematic and comprehensive investigation is missing. The current study therefore investigates the influence of SR on the durability properties of cementitious materials by adding SR emulsion into integral concrete mixture and coating concrete surface with SR. The microscopic and mechanical properties and the durability performance were tested on the integral SR water‐repellent concrete (C-ISR) and SR surface water-repellent concrete (C-SSR). The obtained results indicate that SR application has no impact on hydration reaction and corresponding composition of cement-based materials, while SR addition leads to a reduction in strength and early shrinkage of cement mortar because the added SR delays the hydration reaction. Water-repellent treatment via SR can significantly reduce the water permeability of concrete, which is more apparent for surface water-repellent treatment (SSR). Furthermore, the durability properties were investigated, and the results indicate that integral SR water-repellent treatment (ISR) possesses better properties than SSR, which suggests water-repellent treatment via surface coating as an effective means to improve concrete durability.

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