Recent progress and technical challenges in using calcium sulfoaluminate (CSA) cement

The manufacture of Portland cement entails high energy and environmental costs, and various solutions have been implemented in recent years to mitigate this negative impact. These solutions include improvements in the manufacture of cement clinker or the use of supplementary cementitious materials (SCMs), such as fly ash (FA) or slag as a replacement for a portion of the clinker in cement. The incorporation of these SCMs in cement may increase its radiological content as they are naturally occurring radioactive materials (NORMs). The Activity Concentration Index (ACI) is a screening tool established in the European EURATOM Directive 2013/59 to determine the radiation protection suitability of a final construction material. The ACI is determined by the activity concentrations of 226Ra, 232Th and 40K, usually determined by gamma spectrometry. The methodology of gamma spectrometry is accurate and appropriate, but this technique is not available in all laboratories. For this reason, and taking into account that there is a relationship between the chemical and radiological composition of these building materials, a new approach is proposed to determine the radiological content of these materials from a chemical analysis such as X-ray fluorescence (XRF). In this paper, principal component analysis (PCA) is used to establish the relationships between the chemical composition and radiological content of cements, FAs, and slags of different natures. Through PCA it was possible to group the cements based on two variables: CaO content and Fe2O3–Al2O3–TiO2 content. A lower correlation was observed for the FAs and slags, as the sample scores were centered around the origin of the coordinates and showed greater dispersion than the cements. The clusters obtained in the HJ–Biplots allowed the determination, using multiple regression, of models relating the activity concentration of 226Ra, 232Th (212Pb), and 40K to the oxide percentages obtained for the three matrices studied. The models were validated using five cements, one FA and one slag with relative percentage deviations (RSD(%)) equal to or less than 30% for 89% of the activity concentrations and 100% of the ACI determined.

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“… Calcium sulfoaluminate cements (CSA), have as main phases ye’elimite (

) and belite (

). A feature to highlight in this type of cement is that they have a low carbon footprint [ 21 , 22 , 23 ]. …”

Section: Introductionmentioning

confidence: 99%

New Approach to Determine the Activity Concentration Index in Cements, Fly Ashes, and Slags on the Basis of Their Chemical Composition

et al. 2023

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“…In the latter case, the risk of pipe blockage is reduced because the accelerator is not premixed. Nevertheless, the accurate dosing of the accelerator into fresh cement-based materials remains challenging [22,23]. The second objective is to formulate a 3D printable mixture with excellent adhesion properties in both fresh and hardened states, thus preventing detaching failures at the interface.…”

Section: Challengesmentioning

confidence: 99%

3D concrete printing for tunnel linings: Opportunities and challenges

Tao,

Yuan

2024

IOP Conf. Ser.: Earth Environ. Sci.

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The use of shotcrete for hard rock tunnel linings has drawbacks such as irregular surfaces and rebounds. By contrast, extrusion-based 3D concrete printing presents a promising solution with precise deposition and reduced rebound. This study discusses the potential of 3D printing for tunnel linings, focusing on mitigating shear failure and addressing interfacial detachment. Achieving high strength early for stable adhesion to rock surfaces is paramount for countering shear failure. A twin-pipe pumping system was introduced utilizing a helical static mixer to blend concrete involving chemical triggers, effectively managing the stiffness and fluidity during pumping. In addition, the adhesion to the substrate must be addressed. Based on the above discussion, this study offers insights into the fundamental challenges, paving the way for advancing extrusion-based 3D concrete printing for tunnel linings.

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“…CSA raw meal contains lower content of limestone than ordinary Portland cement (OPC) raw meal, leading to reduced CO 2 emissions during the calcination of CSA clinker [ 2 , 3 , 4 ]. Meanwhile, the calcination temperature required for producing CSA clinker is lower by 100–200 °C compared to the clinkerization process of OPC, resulting in less energy consumption [ 5 , 6 ]. Moreover, the emissions of SO 2 are nearly negligible when the calcination of CSA clinker is under oxidizing atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Performance and Chloride Penetration of Calcium Sulfoaluminate Concrete in Marine Tidal Zone

Tang

Zhan

et al. 2023

Materials

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The enhancement of the durability of sulfoaluminate cement (CSA) in marine environments is of great importance. To this end, an investigation was carried out involving the placement of CSA concrete in the tidal zone of Zhairuoshan Island, Zhoushan, China, and subjected to a 20-month marine tidal exposure test. The comparison was made with ordinary Portland cement (OPC) concrete to evaluate the effectiveness of the former. The test findings indicate that the compressive strength of both types of concrete is reduced by seawater dry-wet cycling, and the porosity of the surface concrete is increased. However, the compressive strength of CSA concrete is observed to be more stable under long-term drying–wetting cycles. When the ettringite in the CSA surface concrete is decomposed due to carbonization and alkalinity reduction, its products will react with Ca2+ and SO42− in seawater to regenerate ettringite to fill in the concrete pores, making the concrete strength more stable and hindering chlorine penetration. Furthermore, CSA concrete exhibits a higher capillary absorption capacity than OPC concrete, which results in chloride accumulation on its surface. However, the diffusion capacity of chloride in CSA concrete is significantly lower than that in OPC concrete.

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Recent progress and technical challenges in using calcium sulfoaluminate (CSA) cement

Cited by 84 publications

References 171 publications

New Approach to Determine the Activity Concentration Index in Cements, Fly Ashes, and Slags on the Basis of Their Chemical Composition

New Approach to Determine the Activity Concentration Index in Cements, Fly Ashes, and Slags on the Basis of Their Chemical Composition

3D concrete printing for tunnel linings: Opportunities and challenges

Mechanical Performance and Chloride Penetration of Calcium Sulfoaluminate Concrete in Marine Tidal Zone

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