Study of Mechanical Properties and Durability of Alkali-Activated Coal Gangue-Slag Concrete

Zhu, Hongguang; Yang, Sen; Li, Weijian; Li, Zonghui; Fan, Jun; Shen, Zhengyan

doi:10.3390/ma13235576

Cited by 29 publications

(16 citation statements)

References 37 publications

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“…The LN 2 jet is shot radially from the main borehole into multiple branches to create a complex lateral fracture network (Figure ). The casing is run vertically, the well is cemented, and the tubing and deflector are lowered into the vertical wellbore . The deflector is anchored to the target layer, and the nozzles for the high-pressure hose and the coiled tubing are introduced into the hole.…”

Section: Ln2 Fracturing Processesmentioning

confidence: 99%

“…The casing is run vertically, the well is cemented, and the tubing and deflector are lowered into the vertical wellbore. 185 The deflector is anchored to the target layer, and the nozzles for the high-pressure hose and the coiled tubing are introduced into the hole. The abrasive LN 2 is pumped to the drill side through the nozzle.…”

Section: Mechanisms Of Ln 2 Fracturingmentioning

confidence: 99%

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Advances in Liquid Nitrogen Fracturing for Unconventional Oil and Gas Development: A Review

et al. 2022

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Liquid nitrogen (LN 2 ) fracturing is an anhydrous fracturing technology that enhances coal permeability and supports unconventional oil and gas exploitation. In this Review, we provide a systematic review of five aspects of LN 2 fracturing. They are the history of the technology's development, research topics, factors influencing fracturing efficiency, fracturing mechanism, and engineering processes and systems. Liquid nitrogen fracturing transforms coal and rock pore structure through mechanisms such as low temperature, freeze−thaw damage, and gas expansion. It changes coal and rock mechanical properties and improves the pore penetration and efficiency of unconventional oil and gas extraction. However, in-depth studies are still required in many areas. They include theoretical studies of twophase nitrogen flow in coal and rock, development of technical equipment to support field operations, and plans to monitor and evaluate fracturing efficiency. On the basis of the advances in LN 2 fracturing research and the challenges, we conclude that future research should focus on multiphase flow and field equipment and technology.

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Section: Ln2 Fracturing Processesmentioning

confidence: 99%

Section: Mechanisms Of Ln 2 Fracturingmentioning

confidence: 99%

Advances in Liquid Nitrogen Fracturing for Unconventional Oil and Gas Development: A Review

et al. 2022

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“…Ma H. et al studied the effect of slag on the strength of coal gangue-based geopolymer samples and found that the compressive strength of coal gangue-based geopolymer samples with 50% slag content increased rate was 55.98% [ 16 ]. Zhu H. et al measured the compressive strength of coal gangue slag concrete and mixed coal gangue and slag as binder with sand to prepare geopolymer concrete with compressive strength of 62.1 MPa at 28 days [ 17 ]. Gao X. et al mixed coal gangue with 60% mineral powder, and the compressive strength of coal-gangue-based geopolymer could reach 51.7 MPa at 28 days [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

Compressive and Flexural Properties of Ultra-Fine Coal Gangue-Based Geopolymer Gels and Microscopic Mechanism Analysis

Yang

Zhang

Lin

2022

Gels

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Geopolymer gel that possesses advantageous features of fast setting, high strength, and good durability is increasingly used in civil engineering, including rapid retrofit projects, roadway, and other construction projects. Furthermore, geopolymer gel is also a green and economical material as it derives from solid wastes. In this study, activators with different sodium silicate modulus and alkali content were used to activate ultrafine coal gangue and slag powder to prepare coal-gangue-based geopolymers with high strength. To study the influence of slag powder content, sodium silicate modulus, and alkali activator content on strength, a two-stage design was adopted. In the first stage, the orthogonal test with three factors and four levels (10–40% slag, 0.4–1.0 modulus, 16–22%) was used to obtain the influence of each factor on the strength and select the design range of the specimen mix ratio with higher strength. In the second stage, based on the orthogonal experiment, the scope was narrowed to continue to find the optimal excitation scheme and the relationship between the influencing factors and strength. Further, mineral compositional, microstructural, functional group and elemental analyses were performed using X-ray diffraction technique, IR infrared diffraction, electron microscope observation and energy spectrum analysis to elucidate the mechanisms of the strength development. The results show that the factors affecting the geopolymer’s strength were in the order of slag content > alkali content > modulus. The optimum dosage of alkali activator was 18–20%, and the sodium silicate modulus was 0.6–0.8, and the compressive and flexural strength could reach above 40 MPa and 5.9 MPa, respectively. The compressive strength and modulus were in a parabolic relationship. Three types of cementing gels (N-A-S-H, C-A-S-H, and C-N-A-S-H) that were characterized with dense structure and high strength were identified from coal gangue and slag powder after alkali excitation.

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“…Based on the classic Aas-Jakobsen fatigue life equation [14], Yu et al [15] established the equations for determining the freeze-thaw fatigue damage in concrete subjected to water freeze-thaw and salt freeze-thaw conditions, and Tian et al [16] proposed a prediction model for the degree of damage caused to concrete when subjected to salt freeze-thaw and flexural load combined. In addition, some classic and well-known mathematical functions or equations are often used to characterize freeze-thaw damage to concrete, such as the parabolic function [17], the Boltzmann equation [18], the inverse logistic function [19], the power function [20] and the exponential function [21].…”

Section: Introductionmentioning

confidence: 99%

Freeze-thaw damage evaluation and model creation for concrete exposed to freeze–thaw cycles at early-age

Liu

Sas

et al. 2021

Construction and Building Materials

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Concrete subjected to freeze-thaw cycles action at early-age will suffer serious physical damage, resulting in degradation of the concrete's performance. The subsequent curing conditions after early-age freeze-thaw cycles (E-FTCs) are critical to the development of the properties of frost-damaged concrete. Four test environments were set up for this study, based on different numbers of E-FTCs and subsequent curing conditions. The later-age resistance to freeze-thaw of concrete exposed to E-FTCs was evaluated by analysing the influence of precuring times and curing conditions. Results show that the earlier the FTCs occur, the worse the later-age freeze-thaw resistance is. In particular, for the frost-damaged concrete with a pre-curing time of 18 h, its freeze-thaw resistance is significantly worse than that of other concretes that have a longer pre-curing time. The increase in the number of E-FTCs exacerbates the damage to early-age concrete, which causes the reduced laterage freeze-thaw resistance. Subsequent water curing can significantly improve the freeze-thaw resistance of damaged concrete, while air curing is the least effective. Based on previous freeze-thaw damage models, prediction models for concrete exposed to E-FTCs were created by using the test data obtained in this study. The critical pre-curing strengths which can ensure that the damaged concrete has satisfactory frost resistance at laterage were thus obtained. For concrete structures expected to experience E-FTCs, adequate pre-curing strength and good re-curing conditions are essential.Abbreviations: DF, Durability factor; E-FTC, Early-age freeze-thaw cycle; FTC, Freeze-thaw cycle; MLR, Mass loss rate; RDME, Relative dynamic modulus of elasticity; 10-WC, Cured in water to age 28 d after 10 E-FTCs; 20-SC, Cured in standard curing room to age 28 d after 20 E-FTCs; 20-WC, Cured in water to age 28 d after 20 E-FTCs; 20-NC, Cured in natural air to age 28 d after 20 E-FTCs.

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Study of Mechanical Properties and Durability of Alkali-Activated Coal Gangue-Slag Concrete

Cited by 29 publications

References 37 publications

Advances in Liquid Nitrogen Fracturing for Unconventional Oil and Gas Development: A Review

Advances in Liquid Nitrogen Fracturing for Unconventional Oil and Gas Development: A Review

Compressive and Flexural Properties of Ultra-Fine Coal Gangue-Based Geopolymer Gels and Microscopic Mechanism Analysis

Freeze-thaw damage evaluation and model creation for concrete exposed to freeze–thaw cycles at early-age

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