Effect of Gypsum on Hydration and Hardening Properties of Alite Modified Calcium Sulfoaluminate Cement

Calcium sulphoaluminate cement (CSA) has the characteristics of quick hardening, high early strength and high impermeability, however its strength growth persistence in the middle and late stages (after the age of 3 days) is poor. In order to improve this disadvantage, the pilot production of alite (C3S) modified CSA (AMCSA) clinker was carried out by liquid phase manipulation and barium ion doping technology. The effects of different dosages of gypsum on the hydration and hardening properties of AMCSA, such as setting time, hydration rate, compressive strength and hydration products, were studied. The results show that the mineral content of ye’elimite, C2S, C3S and iron phase in the calcined AMCSA clinker are 48.5 wt.%, 32.6 wt.%, 11.7 wt.% and 7.2 wt.% respectively, which are close to the designed mineral composition. The stable coexistence of ye’elimite and C3S in the same clinker system is realized. The initial and final setting time of AMCSA are retarded with the increasing gypsum dosage. When the gypsum dosage is 15 wt.% under the experimental conditions in this study, the AMCSA mortar reaches the highest compressive strength at every age. The strength of AMCSA mortar at 28 days is still significantly improved compared with that at 3 days, which indicates that the shortcoming of the low strength growth persistence of CSA in the middle and late stages is improved.

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Effect of Iron Phase on Calcination and Properties of Barium Calcium Sulfoaluminate Cement

Materials ◽

10.3390/ma14195813 ◽

2021 ◽

Vol 14 (19) ◽

pp. 5813

Author(s):

Jun Chang ◽

Jixin Zhang ◽

Yanchen Yuan ◽

Kai Cui

Keyword(s):

Compressive Strength ◽

Liquid Phase ◽

Eutectic Point ◽

Material System ◽

Phase Content ◽

Calcium Sulfoaluminate Cement ◽

Early Hydration ◽

Calcium Sulfoaluminate ◽

Eds Analysis ◽

Iron Phase

In this paper, the effect of iron phase content on the calcination and properties of clinker and barium calcium sulfoaluminate cement was studied. The compressive strength of the samples was tested and combined with an XRD and SEM-EDS analysis, and the microstructure and composition of the barium calcium sulfoaluminate clinker and hydrated samples were characterized. The results showed that the oval-shaped particles were C2S minerals, and the hexagonal plate-shaped or rhombohedral dodecahedral particles were C2.75B1.25A3S¯. The Ba element was mainly distributed in the barium calcium sulfoaluminate region, and some of it was dissolved in C2S; the Fe element was distributed between C2.75B1.25A3S¯ and C2S crystal grains in the form of an iron phase solid solution, which acted as a solvent. When the iron phase composition was C4AF and the iron phase content was 5%, the early hydration and later strength were better, and the compressive strength after curing for 1, 3 and 28 days was 73.2 MPa, 97.9 MPa and 106.9 MPa, respectively. A proper amount of the iron phase can reduce the eutectic point of the sintered mature material system, increase the amount of liquid phase, reduce the viscosity of the liquid phase, effectively accelerate the migration of mineral ions and promote the formation and growth of minerals.

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Properties of calcium sulfoaluminate cement-based grouting materials with LiAl-layered double hydroxides slurries

Advanced Composites Letters ◽

10.1177/2633366x20926522 ◽

2020 ◽

Vol 29 ◽

pp. 2633366X2092652 ◽

Cited By ~ 1

Author(s):

Haiyan Li ◽

Xianping Wang ◽

Xuemao Guan ◽

Dinghua Zou

Keyword(s):

Compressive Strength ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Layered Double Hydroxides ◽

Setting Time ◽

Hydration Products ◽

Calcium Sulfoaluminate Cement ◽

Calcium Sulfoaluminate ◽

Double Hydroxides

In this study, LiAl-layered double hydroxides Lithium aluminum hydrotalcite (LiAl-LDH) with different specific surface area were prepared by the separate nucleation and aging steps (SNAS) method and then were employed to prepare calcium sulfoaluminate cement-based grouting material (CBGM) paste. The influence of LiAl-LDH slurries on fresh and hardened properties of the CBGM paste was investigated in terms of fluidity, stability, setting time, and compressive strength. Additionally, the hydration process and hydration products of the CBGM paste were characterized by hydration heat, X-ray diffraction, differential thermal analysis–thermogravimetry, and Fourier transform infrared analyses. The acquired results illustrated that LiAl-LDH with larger specific surface area led to a faster hydration rate at early age, a lower fluidity, a shorter setting time, and a higher stability. Furthermore, due to the crystal nucleation effect, the addition of LiAl-LDH slurries did not cause a new phase to form but changed the morphology and increased the amount of hydration products, yielding higher compressive strength.

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Using of Different Type Cement in Solidification/Stabilization of MSWI Fly Ash

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.291-294.1870 ◽

2011 ◽

Vol 291-294 ◽

pp. 1870-1874 ◽

Cited By ~ 2

Author(s):

Guo Xia Wei ◽

Han Qiao Liu ◽

Shu Guang Zhang

Keyword(s):

Heavy Metals ◽

Compressive Strength ◽

Fly Ash ◽

Setting Time ◽

Solid Matrix ◽

Cement Type ◽

Calcium Sulfoaluminate Cement ◽

Mswi Fly Ash ◽

Calcium Sulfoaluminate ◽

Aluminate Cement

Solidification tests of MSWI fly ash (FA) with three types of cement including ordinary Portland cements (OPC), calcium sulfoaluminate cement(CSA) and calcium aluminate cement (CAC) were carried out to discuss the effect of cement type on of the FA-cement solid matrix by means of setting time, compressive strength and heavy metals leachability. Results show that the setting time of the FA-cement mixtures using CSA and CAC is shorter than that of OPC. According to compressive strengths demand and the standard of landfill site of municipal solid waste, the dosage of OPC should be limited about 35% by weigh, the dosage of CAC should be limited about 25% by weigh, and the dosage of CSA should be limited more than 40% by weigh.

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Performance and Durability of Rendering and Basecoat Mortars for ETICS with CSA and Portland Cement

Infrastructures ◽

10.3390/infrastructures6040060 ◽

2021 ◽

Vol 6 (4) ◽

pp. 60

Author(s):

Tiago Trigo ◽

Inês Flores-Colen ◽

Luís Silva ◽

Nuno Vieira ◽

Ana Raimundo ◽

...

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Energy Consumption ◽

Portland Cement ◽

Bending Strength ◽

Setting Time ◽

Cement Matrix ◽

Calcium Sulfoaluminate Cement ◽

Calcium Sulfoaluminate ◽

Composite Systems

The production of Portland cement (OP) is commonly associated to significant level of energy consumption and gas emissions. The use of calcium sulfoaluminate cement (CSA) can be a sustainable alternative binder, since its production releases about half of the CO2 emissions and its clinker requires 200 °C lower temperatures, when compared to OP. Furthermore, CSA has fast setting time and achieves higher strength in shorter periods, as well as reduced shrinkage. This paper discusses the incorporation of CSA in rendering mortars and basecoat mortars for ETICS (External Thermal Insulation Composite Systems). The physical-mechanical properties of mortars made with OP and CSA cements were experimental evaluated. The results showed that the introduction of CSA generally improves shrinkage, compressive strength, water absorption at low pressure, enhances the tensile bending strength and decreases the setting time. The amount of CSA introduced into the mixture significantly affected the properties of the cement matrix.

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Utilization of Carbide Slag by Wet Grinding as an Accelerator in Calcium Sulfoaluminate Cement

Materials ◽

10.3390/ma13204526 ◽

2020 ◽

Vol 13 (20) ◽

pp. 4526

Author(s):

Xianyue Gu ◽

Hongbo Tan ◽

Xingyang He ◽

Olga Smirnova ◽

Junjie Zhang ◽

...

Keyword(s):

Compressive Strength ◽

Ph Value ◽

Setting Time ◽

Calcium Sulfoaluminate Cement ◽

Initial Strength ◽

Calcium Sulfoaluminate ◽

Ettringite Formation ◽

Carbide Slag ◽

Novel Approach ◽

Wet Ground

In this study, wet-ground carbide slag (i.e., WGCS) was utilized as an accelerator in calcium sulfoaluminate cement (CSA) for obtaining considerably faster setting processes for some special engineering processes such as plugging projects and rapid repair engineering. The WGCS–CSA system was designed, in which the replacement ratio of CSA by carbide slag was chosen as 4%, 8% and 12%. The setting time and compressive strength were measured, and the mechanism of the system hydration was studied in detail by means of calorimetry, XRD, thermogravimetry (TG) and SEM. The results showed that WGCS shortened the setting time of cement and significantly augmented the early strength. The addition of 8% of WGCS contributed to increasing the 2-h compressive strength from 4.2 MPa to 32.9 MPa. The decrease in the setting time and the increase in the initial strength were mainly attributed to the high initial pH value of the liquid phase and the high content of calcium ions in WGCS. Both these factors contributed to the ettringite formation and, at the same time, to the transformation of the morphology at a later time. Such results testify that WGCS can be used as an accelerator in the CSA system and also that it provides a novel approach to the reutilization of carbide slag.

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Effect of Naphthalene-Based Superplasticizer and Polycarboxylic Acid Superplasticizer on the Properties of Sulfoaluminate Cement

Materials ◽

10.3390/ma14030662 ◽

2021 ◽

Vol 14 (3) ◽

pp. 662

Author(s):

Yonghua Wu ◽

Qiqi Li ◽

Guoxin Li ◽

Shiying Tang ◽

Mengdie Niu ◽

...

Keyword(s):

Compressive Strength ◽

Setting Time ◽

Hydration Products ◽

Polycarboxylic Acid ◽

X Ray Diffraction ◽

Calcium Sulfoaluminate Cement ◽

X Ray ◽

Initial Setting Time ◽

Calcium Sulfoaluminate ◽

Initial Setting

In order to study what the effect of superplasticizers on the setting time, fluidity and compressive strength of calcium sulfoaluminate cement (CSA) a naphthalene-based superplasticizer (BNS) and a polycarboxylic acid superplasticizer (PC) were selected to interact with CSA pastes and ye’elimite, respectively. X-ray diffraction (XRD), thermogravimetric (TG) analysis and scanning electron microscopy (SEM) analytical methods were used to investigate the class, amount and microstructure of the CSA pastes and ye’elimite pastes hydration products under the effect of the superplasticizers. The results showed that the addition of BNS can promote ettringite generation and thus improve the early compressive strength. As the addition of BNS increased from 0.8 wt% to 2.0 wt%, the initial setting time was prolonged 10 min, the final setting time was prolonged 7 min, the 5 min fluidity was improved from no fluidity to 220 mm. However, as the addition of PC increased from 0.08 wt% to 0.20 wt%, the setting time of the PC just changed within 3 min; the 5 min fluidity increased from 110 mm to 195 mm and no 15 min fluidity at all was observed. AS seen by SEM, it can be stated that generated ettringite under the addition of PC was layered and lacking bonding, and its morphology changed from rod-like to flake-like, leading to a decrease in early compressive strength.

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Effect of Flue Gas Desulfurization Gypsum on the Properties of Calcium Sulfoaluminate Cement Blended with Ground Granulated Blast Furnace Slag

Materials ◽

10.3390/ma14020382 ◽

2021 ◽

Vol 14 (2) ◽

pp. 382 ◽

Cited By ~ 1

Author(s):

Danying Gao ◽

Zhenqing Zhang ◽

Yang Meng ◽

Jiyu Tang ◽

Lin Yang

Keyword(s):

Blast Furnace ◽

Mechanical Strength ◽

Flue Gas ◽

Blast Furnace Slag ◽

Setting Time ◽

Flue Gas Desulfurization ◽

Calcium Sulfoaluminate Cement ◽

Calcium Sulfoaluminate ◽

Granulated Blast Furnace Slag ◽

Furnace Slag

This work aims to investigate the effect of additional flue gas desulfurization gypsum (FGDG) on the properties of calcium sulfoaluminate cement (CSAC) blended with ground granulated blast furnace slag (GGBFS). The hydration rate, setting time, mechanical strength, pore structure and hydration products of the CSAC-GGBFS mixture containing FGDG were investigated systematically. The results show that the addition of FGDG promotes the hydration of the CSAC-GGBFS mixture and improves its mechanical strength; however, the FGDG content should not exceed 6%.

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Properties of Calcium Sulfoaluminate Cement Mortar Modified by Hydroxyethyl Methyl Celluloses with Different Degrees of Substitution

Molecules ◽

10.3390/molecules26082136 ◽

2021 ◽

Vol 26 (8) ◽

pp. 2136

Author(s):

Shaokang Zhang ◽

Ru Wang ◽

Linglin Xu ◽

Andreas Hecker ◽

Horst-Michael Ludwig ◽

...

Keyword(s):

Compressive Strength ◽

Flexural Strength ◽

Bond Strength ◽

Cement Mortar ◽

Retention Rate ◽

Methyl Cellulose ◽

Tensile Bond Strength ◽

Calcium Sulfoaluminate Cement ◽

Calcium Sulfoaluminate ◽

Cement Mortars

This paper studies the influence of hydroxyethyl methyl cellulose (HEMC) on the properties of calcium sulfoaluminate (CSA) cement mortar. In order to explore the applicability of different HEMCs in CSA cement mortars, HEMCs with higher and lower molar substitution (MS)/degree of substitution (DS) and polyacrylamide (PAAm) modification were used. At the same time, two kinds of CSA cements with different contents of ye’elimite were selected. Properties of cement mortar in fresh and hardened states were investigated, including the fluidity, consistency and water-retention rate of fresh mortar and the compressive strength, flexural strength, tensile bond strength and dry shrinkage rate of hardened mortar. The porosity and pore size distribution were also analyzed by mercury intrusion porosimetry (MIP). Results show that HEMCs improve the fresh state properties and tensile bond strength of both types of CSA cement mortars. However, the compressive strength of CSA cement mortars is greatly decreased by the addition of HEMCs, and the flexural strength is decreased slightly. The MIP measurement shows that HEMCs increase the amount of micron-level pores and the porosity. The HEMCs with different MS/DS have different effects on the improvement of tensile bond strength in different CSA cement mortars. PAAm modification can improve the tensile bond strength of HEMC-modified CSA cement mortar.

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Printability and Setting Time of CSA Cement with Na2SiO3 and Gypsum for Binder Jetting 3D Printing

Materials ◽

10.3390/ma14112811 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2811

Author(s):

Okpin Na ◽

Kangmin Kim ◽

Hyunjoo Lee ◽

Hyunseung Lee

Keyword(s):

3D Printing ◽

Sodium Silicate ◽

Setting Time ◽

Sodium Silicate Solution ◽

Preliminary Test ◽

Silicate Solution ◽

Calcium Sulfoaluminate Cement ◽

Calcium Sulfoaluminate ◽

Parametric Studies ◽

Binder Jetting

The purpose of this study is to optimize the composition of CSA (calcium sulfoaluminate) cement with sodium silicate (Na2SiO3) and gypsum for binder jetting 3D printing. The preliminary test was carried out with an applicator to decide the proper thickness of one layer before using the 3D printer. A liquid binder was then selected to maintain the shape of the particles. Based on the results, the optimal mixture of dry materials and a liquid activator was derived through various parametric studies. For dry materials, the optimum composition of CSA cement, gypsum, and sand was suggested, and the liquid activator made with sodium silicate solution and VMA (viscosity modified agent) were selected. The setting time with gypsum and sodium silicate was controlled within 30 s. In case of the delayed setting time and the rapid setting mixture, the jetting line was printed thicker or thinner and the accuracy of the printout was degraded. In order to adjust the viscosity of the liquid activator, 10% of the VMA was used in 35% of sodium silicate solution and the viscosity of 200–400 cP was suitable to be sprayed from the nozzle. With this optimal mixture, a prototype of atypical decorative wall was printed, and the compressive strength was measured at about 7 MPa.

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Influence of Water-Cement Ratio and Type of Mixing Water on the Early Hydration Performance of Calcium Sulphoaluminate (CSA) Cement

Advances in Materials Science and Engineering ◽

10.1155/2021/5557763 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Chuanlin Wang ◽

Meimei Song

Keyword(s):

Compressive Strength ◽

Physical Properties ◽

Setting Time ◽

Hydration Process ◽

Chemical Shrinkage ◽

Cement Ratio ◽

Water Cement Ratio ◽

Influence Of Water ◽

Calcium Sulphoaluminate ◽

Mixing Water

The present work studies the influence of water-cement ratio and types of mixing water on the hydration process and microstructure of calcium sulphoaluminate (CSA) cement. Experimental tests on the setting time, physical properties, compressive strength, chemical shrinkage, X-ray diffraction (XRD), and scanning electron microscopy (SEM) of CSA cement paste were carried out. The XRD analysis confirmed that the main hydration product is ettringite in both freshwater and seawater mixed CSA cement with different w/c ratios. The SEM analysis and physical properties test show that both low w/c ratio and seawater can improve the microstructure of CSA cement. The test results also find out that the high w/c ratio can accelerate the hydration process, extend the setting time, lower the compressive strength, and increase the chemical shrinkage of CSA cement, and the seawater presents a similar influence except for the mechanical property. The seawater increases the compressive strength of CSA cement in the early stage of hydration but will increase the microcracks at the later hydration stage of CSA cement and reduce its mechanical properties.

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