Chemical resistance of eco-concrete – Experimental approach on Ca-leaching and sulphate attack

Steindl, Florian Roman; Baldermann, Andre; Galán, Isabel Moratilla; Sakoparnig, Marlene; Briendl, Lukas; Dietzel, Martin; Mittermayr, Florian

doi:10.1016/j.conbuildmat.2019.06.189

Cited by 19 publications

(2 citation statements)

References 62 publications

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“…At early ages, the ettringite is helpful as it fills the capillary pores and thus makes the cement matrix denser [1]. However, if this reaction continues, even when the cement takes its strength, it leads to damages of the cement matrix due to the stresses generated by the expanded ettringite [1][2][3]. To overcome this problem and enhance the resistance of mortar or concrete of a structural member to the sulfate attack, Sulfate-Resisting (SR)-cement is employed.…”

Section: Introductionmentioning

confidence: 99%

Enhancing the Properties of Sulfate-Resisting Cement

Kammouna

2023

Eng. Technol. Appl. Sci. Res.

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Sulfate-resisting cement is used in construction works when a sulfate attack is probable. This type of cement withstands sulfates due to its low C3A content. On the other hand, the decrease in the quantity of C3A leads to a reduction in the rate of early strength development. To overcome this problem, a hardening accelerator was added to the cement mix. To estimate the effect of the accelerator on some properties of hardened cement, compressive and flexural strength, and drying shrinkage tests were carried out. Four series of cement mortar mixes were made. The hardening accelerator was not added to the control series, while it was added to the others with three different percentages (of cement mass) of 0.5, 1, and 1.5%. The results revealed that the hardening accelerator enhances the compressive strength of all mortar ages while it slightly promotes flexural strength only at early ages. It was also observed that the hardening accelerator strongly inhibits the drying shrinkage strain.

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Section: Introductionmentioning

confidence: 99%

Enhancing the Properties of Sulfate-Resisting Cement

Kammouna

2023

Eng. Technol. Appl. Sci. Res.

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“…As they penetrate through the interconnected porous network of the matrix, sulphates can react with aluminate phases in the matrix to form expansive compounds (secondary ettringtite or secondary gypsum) and cause damage in a process known as external sulphate attack (ESA). Secundary ettringite formation in small pores (<50 nm) has been identified according to [5][6] as the main force to weakening the matrix due the cristallization in the pore. Other types can be adressed as gypsum secondary gypsum or thaumasite formation, aluminathe phases can react with Ca2+ or Na+ [6,7] To mitigate the consequences of the attack, most standards and recommendations rely on the specification of sulphate-resisting (SR) cements characterised by a limited C3A content (generally below 5% by cement weight [6][7]).…”

Section: Introductionmentioning

confidence: 99%

External sulphate attack of sprayed mortars with sulphate-resisting cement: Influence of accelerator and age of exposition

Herrera-Mesen

Salvador

Ikumi

et al. 2020

Cement and Concrete Composites

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This work evaluates the influence of the accelerator type, the cement type and age of exposure on the degradation mechanism and the durability of sprayed mortars subjected to external sulphate attack (ESA). Cores and prisms were extracted from panels sprayed with 8 mortar compositions (with 2 sulphate-resisting cement types and 4 setting accelerators) and then exposed to a sulphate solution at the ages of 7 or 28 days for 400 days. The evolution of the ESA was assessed through XRD, SEM, compressive strength, dimensional variation and ultrasonic pulse velocity. Results show that alkaline accelerators increase drastically the vulnerability of the matrix to the ESA. The degradation is enhanced by the higher solubility of aluminate phases and the increased formation of expansive phases. Results reveal that the use of sulphate-resisting cement might not suffice to mitigate severe material degradation.

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Microstructure development in lacustrine, fine-grained sediments traced by in situ and laboratory testing

Oberhollenzer,

Hauser,

Baldermann

et al. 2024

Int. J. Environ. Sci. Technol.

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Soil microstructure, often defined as the combination of particle arrangement and bonding, can strongly influence the stiffness and strength of sedimentary deposits. As undisturbed soil sampling is a challenging task in fine-grained soils, seismic in situ testing is becoming increasingly more important to investigate its mechanical behaviour. The aim of this article is to evaluate the influences of sediment depositional age and structure-forming processes on the degree of soil structure development in Alpine deposits. Seismic in situ and laboratory testing comprising X-ray diffraction (XRD), scanning electron microscopy (SEM), pore water chemical analysis and hydrochemical modelling were executed at three Austrian test sites, namely Lokalbahn Salzburg, Rhesi and water reservoir Raggal. Based on the comparison of in situ shear wave velocities (VS,SDMT) with bender element results (VS,BE), executed on reconstituted soil specimens, it is shown that the Pleisto–Holocene-aged deposits are characterized by a VS,BE/VS,SDMT ratio of < 1, indicating the presence of microstructure. However, the youngest sediments (< 50 years) exhibit the weakest microstructure (VS,BE/VS,SDMT ≈ 1). The increase of soil structure with sediment age is represented by the updated normalized small-strain rigidity index, K*G, which is situated at the proposed transition between structured and unstructured soils (K*G = 330), ranging between 250 and 350, at all test sites. The development of microstructure can be attributed to the precipitation of calcite (CaCO3) cements in open pores, which strengthens the interparticle bonding between detrital quartz, feldspar, clay minerals and carbonate grains, subsequently reducing the soil`s porosity with increasing sediment age.

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Chemical resistance of eco-concrete – Experimental approach on Ca-leaching and sulphate attack

Cited by 19 publications

References 62 publications

Enhancing the Properties of Sulfate-Resisting Cement

Enhancing the Properties of Sulfate-Resisting Cement

External sulphate attack of sprayed mortars with sulphate-resisting cement: Influence of accelerator and age of exposition

Microstructure development in lacustrine, fine-grained sediments traced by in situ and laboratory testing

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