Experimental Study on the Properties and Hydration Mechanism of Gypsum-Based Composite Cementitious Materials

Liu, Jianping; Song, Ge; Ge, Xiaowei; Liu, Bing; Liu, Kaixin; Tian, Yulin; Wang, Xu; Hu, Zhihang

doi:10.3390/buildings14020314

Cited by 8 publications

(4 citation statements)

References 60 publications

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“…Therefore, the formulation was changed by reducing the concentration of organic and inorganic retardants, called FAG 0.4b, as shown in Table 3 below: Figure 6 shows that the paste system with FAG 0.4b formulation is strongly dependent on the amount of water present in its formulation, as a slight decrease in retarder concentration enabled the formation and saturation of the dihydrate so that there was a gain in consistency with subsequent hardening of the paste (J. Liu et al, 2024), with a thickening time of 375 minutes (6 hours and 15 minutes).…”

Section: Resultsmentioning

confidence: 99%

Gypsum slurries to apply in oil well: An insight into thickening time

Braga,

Freitas

2024

RSD

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Gypsum is widely used in the construction industry, especially as a hydraulic binder. Studies have indicated the use of α-HH gypsum as an alternative material to Portland Cement in oilwell cementing operations, highlighting the reduction in environmental impacts from the reduction of Portland Cement. Calcium Sulphate α-Hemihydrate (CaSO4 . ½ H2O) has been shown to be a promising material to replace Portland Cement in some applications. The hydration of gypsum pastes goes through the process of saturation of the medium with Ca+2 and SO4-2 ions, then the physical phenomenon of crystallization, and finally the phenomenon of hardening, where the crystals formed precipitate producing Dihydrate (CaSO4 . 2H2O). Gypsum pastes harden very quickly, and their pumpability is impaired with thickening times of less than 20 minutes. For applications requiring longer pumpability times, the use of retarding additives is necessary. This research studied the effects of retarding additives in α-HH gypsum paste systems by varying the water-gypsum factor (FAG 0.4; 0.5 and 0.6) using a pressurized consistometer, under conditions of 54 °C and 9500 psi, with the aim of obtaining formulations with admissible thickening times for oil well cementing applications. The results showed that it was possible to develop paste systems with varying thickening times, with intervals of more than 120 minutes. The 0.5 FAG system proved to be more stable at the same retarder concentrations when compared to the 0.4 and 0.6 FAG systems.

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Section: Resultsmentioning

confidence: 99%

Gypsum slurries to apply in oil well: An insight into thickening time

Braga,

Freitas

2024

RSD

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“…Two-factor analysis of variance (ANOVA) with replications was employed to investigate the effects of two independent variables on the observed outcomes. Particle size, temperature, and pressure were manipulated as independent variables to evaluate both their individual impacts and potential interactions [32,33]. An ANOVA was performed on the dataset, which comprised a total of 102 data points.…”

Section: Discussionmentioning

confidence: 99%

Particle Boards from Forest Residues and Bio-Based Adhesive

Krumins,

Vamza,

Dzalbs

et al. 2024

Buildings

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Wood chipboard, common in interior spaces for applications ranging from furniture to decorative panelling, often falls short due to the presence of toxic adhesives, posing risks to both human health and the environment. This research delves into the potential transformation of wood chipboard into a 100% bio-based product. Previous research has shown the possibility of the partial replacement of petrochemical-based adhesives with bio-based adhesives. Hence, previous results do not reach the policy ambitions of the Green Deal of making the Green Transition to a bio-based economy. For chipboard production, logging residues from Latvian State Forests were systematically gathered within two months post-logging, comprising primarily Picea abies and Pinus sylvestris biomass, including branches, needles, bark, and various particles. A custom chipper and Vibrotehnik PM-120 hammer mill were employed for particle size separation into three fractions via sieving: <2.8 mm, 2.8–8 mm, and 8.0–10.0 mm, and combined with binders and hot-pressed into board samples. As a result, particle boards containing 100% bio-based carbon were achieved, demonstrating the possibility of excluding petroleum adhesives from chipboard production, paving the way for new research exploring bio-based binders and conifer bark.

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“…The second exothermic peak occurs in the range of 4-10 h and is characterized as small and short. It is hypothesized that this is related to the generation of calcite and AFt in the gelling system [28][29][30][31]. The third exothermic peak appears after 24 h, which is characterized by a significant long exothermic duration, and it is presumed that this is related to the generation of C-S-H gel, calcite, and the hydrated fossil phase in the gelling system [32,33].…”

Section: Heat Of Hydrationmentioning

confidence: 99%

Analysis of Hydration Mechanism of Steel Slag-Based Cementitious Materials under Saline–Alkaline-Coupled Excitation

Liu,

et al. 2024

Buildings

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In order to realize the resourceful, large-scale, and high-value utilization of steel slag, which is a bulk industrial solid waste, and to reduce the use of cement-based cementitious materials, this study adopted the coupled excitation effect of sodium carbonate–magnesium oxide–desulfurization gypsum to excite steel slag-based cementitious materials, and it preliminarily investigated the hydration process of the steel slag-based cementitious system by the analysis of the heat of hydration of the cementitious materials and the pH value of the pore solution. The hydration products and microscopic morphology of the steel slag-based gelling material were initially investigated by XRD and SEM technical means on the gelling system. The results showed that the hydrolysis of the exciter and the dissociation of the active components in the steel slag provided an alkaline environment and relevant ions for the gelling system, which promoted the generation of the AFt and hydrotalcite phases. Subsequently, the AFt provided ungenerated sites for C-S-H gels as well as calcites, and the hydrotalcite phase accelerated the transformation of the carbonate phase in the gelling system, which promoted the synergistic effect of the hydration of the steel slag and mineral slag. Eventually, a large number of C-S-H gels, calcites, and other hydration products were generated in the gelling system under the synergistic effect of the hydration of the steel slag and slag, which was manifested in the improvement in the mechanical properties at the macrolevel. In addition, this study also standardized 28 d steel slag-based gelling for carbonization maintenance, and the data show that a carbonization temperature of 70 °C, CO2 pressure of 0.7 MPa, and carbonization time of 30 min achieved the best results, with a strength of up to 51.22 MPa, illustrating that steel slag-based gelling materials are safe and can be used for the green storage of CO2.

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Experimental Study on the Properties and Hydration Mechanism of Gypsum-Based Composite Cementitious Materials

Cited by 8 publications

References 60 publications

Gypsum slurries to apply in oil well: An insight into thickening time

Gypsum slurries to apply in oil well: An insight into thickening time

Particle Boards from Forest Residues and Bio-Based Adhesive

Analysis of Hydration Mechanism of Steel Slag-Based Cementitious Materials under Saline–Alkaline-Coupled Excitation

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