Study on the inorganic synthesis from recycled cement and solid waste gypsum system: Application in grouting materials

Lin, Chensheng; Dai, Wenjie; Li, Zhaofeng; Wang, Yansheng

doi:10.1016/j.conbuildmat.2020.118930

Cited by 23 publications

(5 citation statements)

References 41 publications

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“…When the phosphogypsum was increased to 30% (PRS-3), the 7-day and 28-day strength decreased significantly; the 7-day compressive strength was 13 MPa and the 28-day compressive strength was 20 MPa, which are increases of only 16% and 43% compared with PRS-0 ( Figure 11 ). Numerous studies have shown [ 12 , 21 , 38 ] that gypsum can accelerate the pozzolanic reaction of slag, fly ash, and other materials, generate more C-S-H and an ettringite-reinforced matrix, and improve the strength. Usually, when the content of phosphogypsum is 15–20%, the composite cementitious material has the best strength [ 9 ].…”

Section: Resultsmentioning

confidence: 99%

“…However, the more complicated pretreatment methods can easily cause secondary pollution and are not conducive to large-scale production and ecological protection. Interestingly, Lin et al [ 12 ] studied the effect of phosphogypsum on the properties of recycled cement. The study found that phosphogypsum can accelerate the formation of C-S-H and ettringite to improve the strength of recycled cement.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure and Key Properties of Phosphogypsum-Red Mud-Slag Composite Cementitious Materials

Chen²,

Lin

et al. 2022

Materials

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Due to the low content of silicon and aluminum in red mud and the low reaction activity of red mud, when it was used to prepare composite cementitious materials, it was necessary to assist other aluminosilicates and improve their activity by certain methods. In this study, it was proposed to add slag to increase the percentage of silicon and aluminum in the system, and to improve the reactivity of the system through the activation effect of sulfate in phosphogypsum. The effects of slag and phosphogypsum contents on the mechanical properties and microstructures of composite cementitious materials were studied. X-ray diffraction analysis (XRD), thermogravimetric analysis (TG-DTG), and scanning electron microscopy (SEM) were used to analyze the effects of slag and phosphogypsum contents on the hydration products, microstructure, and strength formation mechanism of composite cementitious materials. The results show that with the increase of slag, the strength of the composite cementitious material increases gradually. When the slag content is 50%, the 28-day compressive strength reaches a maximum of about 14 MPa. Compared with the composite material without phosphogypsum, the composite cementitious material with 10–20% phosphogypsum showed higher strength properties, in which the 28-day compressive strength exceeds 24 MPa. The main reason for this is that the sulfate in phosphogypsum can cause the composite cementitious material to generate a large amount of ettringite and accelerate the dissolution of red mud and slag, increasing the release of aluminates, silicates, and Ca2+ to form more C-(A)-S-H and ettringite. In addition, a large amount of C-(A)-S-H makes ettringite and unreacted particles combine into a uniform and compact structure, thus improving the strength. When the content of phosphogypsum exceeds 40%, the 28-day compressive strength of the composite cementitious material drops below 12 MPa due to the presence of fewer hydration products and the expansion of ettringite.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microstructure and Key Properties of Phosphogypsum-Red Mud-Slag Composite Cementitious Materials

Chen²,

Lin

et al. 2022

Materials

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“…The intensity of most mineral diffraction peaks of steel slag decreases, while some peaks, such as Ca 2 Fe 2 O 5 , Ca 2 SiO4, and Ca 2 C 2 O 4 , decrease obviously, and are almost invisible in the XRD diffraction patterns. Most minerals on the surface of the steel slag can hydrate to form hydrated calcium silicate (C-S-H) during the process of water erosion, especially Ca 2 SiO 4 and Ca 3 SiO 4 , which are invisible in the XRD diffraction patterns because of their amorphous forms [ 49 , 50 , 51 ]. Table 11 shows the changes in the chemical elements in the steel slag before and after the treatment with water erosion.…”

Section: Resultsmentioning

confidence: 99%

Study on the Performance of Steel Slag and Its Asphalt Mixture with Oxalic Acid and Water Erosion

et al. 2022

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The reuse of steel slag, a large-scale solid waste from steel production, has good social and environmental benefits. The application of a steel slag asphalt mixture is mainly hindered by its volume expansion in water. The expansion of steel slag can be inhibited by oxalic acid. The expansion rate and adhesion of steel slag were investigated, and the immersion stability of steel slag and its asphalt mixture was evaluated by water erosion. By means of XRD, XRF, TG, SEM, etc., the influence mechanism of oxalic acid and water erosion on the properties of steel slag and its asphalt mixture was discussed. The results show that oxalic acid can not only inhibit the expansion of steel slag but also improve its crush resistance, with a reduction in the expansion rate of steel slag by 53%. Oxalic acid is able to leach alkaline metal elements, reducing its adhesion with asphalt. After 10 days of water erosion, the rutting stability and bending crack resistance of the treated steel slag mixture decreased by 37% and 43.2%, respectively. Calcium oxalate is generated on the surface of treated steel slag, which improves the surface compactness, effectively inhibits the expansion of steel slag caused by water erosion, and improves the performance of steel slag and its asphalt mixture. Water erosion can accelerate the hydration and shedding of calcium-containing substances on the surface of steel slag, reduce the adhesion of steel slag, and lead to degradation in the performance of steel slag and its asphalt mixture. Oxalic acid is able to effectively inhibit the expansion of steel slag, and the treated steel slag can be used as recycled aggregate in asphalt mixture, effectively solving the problems of road aggregate deficiency and environmental pollution caused by steel slag.

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“…Mujah et al [33] enhanced the mechanical strength of a slurry by incorporating palm oil fuel ash into ordinary cement. Lin et al [34] examined the impact of phosphogypsum and flue gas desulfurization gypsum on the performance and microstructure of thermally activated recycled concrete. Different gypsum types extended the initial setting times and improved the fluidity and mechanical properties of the grouts.…”

Section: Inorganic Grouting Materialsmentioning

confidence: 99%

A State-of-the-Art Review on the Study of the Diffusion Mechanism of Fissure Grouting

Du,

Li,

Fang

et al. 2024

Applied Sciences

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China is renowned for its extensive underground engineering projects and the complex geological and hydrological conditions it faces. Grouting treatment technology is widely employed in deep-buried mines and tunnels, where grouting parameters such as materials, pressure, volume, and hole arrangement significantly impact the effectiveness of grouting. This review paper comprehensively examines current research on grouting materials, theories, experiments, and numerical simulations. It summarizes the various factors that must be considered during the grouting process of fissures and explores the diffusion mechanisms of grout under their influence. Furthermore, further research is needed on the mechanisms and treatment methods for poor grouting in rock masses, the distribution patterns of fissures, optimization methods for grouting parameters, and grout quality assessment techniques. Future research should focus on developing more efficient experimental methods with higher accuracy levels while advancing grouting technologies. Establishing comprehensive and accurate rock mass models along with improving monitoring capabilities are also crucial aspects to consider. Therefore, studying the diffusion mechanisms of grout in fissured rock masses is of significant importance for the practical operation of underground engineering projects.

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Study on the inorganic synthesis from recycled cement and solid waste gypsum system: Application in grouting materials

Cited by 23 publications

References 41 publications

Microstructure and Key Properties of Phosphogypsum-Red Mud-Slag Composite Cementitious Materials

Microstructure and Key Properties of Phosphogypsum-Red Mud-Slag Composite Cementitious Materials

Study on the Performance of Steel Slag and Its Asphalt Mixture with Oxalic Acid and Water Erosion

A State-of-the-Art Review on the Study of the Diffusion Mechanism of Fissure Grouting

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