Damage constitutive model of coal gangue concrete under freeze-thaw cycles

Qiu, Jisheng; Zhou, Yunxian; Vatin, Nikolay; Guan, Xiao; Sultanov, S. B.; Khemarak, Khon

doi:10.1016/j.conbuildmat.2020.120720

Cited by 68 publications

(26 citation statements)

References 13 publications

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“…Consequently, the furnace slag was highly active and weakly alkaline. The phase composition of furnace slag is primarily a glass matrix that is made of nCaO•SiO 2 in which basic oxides react with SiO 2 , Al 2 O 3 , and Fe 2 O 3 after the hydration reaction, thus showing the hard cementing property of the effluent [18][19][20][21][22]. Based on the chemical reaction mechanism of the material and strength formation mechanism of the specimen, it is feasible to use furnace slag as an admixture of the pavement base.…”

Section: Methodsmentioning

confidence: 99%

Mechanical Properties of Furnace Slag and Coal Gangue Mixtures Stabilized by Cement and Fly Ash

Zhang

Yan

et al. 2021

Materials

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The mechanical properties and strength formation mechanism of cement–fly-ash-stabilized slag–coal gangue mixture were examined using an unconfined compressive strength test, splitting strength test, triaxial test, and scanning electron microscopy to solve the limitations of land occupation and environmental pollution that is caused by fly ash from the Xixia District thermal power plant in Yinchuan, slag from the Ningdong slag yard, and washed coal gangue. Its performance as a pavement base mixture on the road was investigated. The results demonstrated that as the slag replacement rate increased, the maximum water content increased while the maximum dry density decreased. The addition of slag reduced the unconfined compressive strength and splitting strength of the specimens; furthermore, the higher the slag substitution rate, the lower the unconfined compressive strength and splitting strength of the specimens. As the cement content increased, the specimen’s unconfined compressive strength increased. Based on the principle of considering the mechanical properties and economic concerns, the slag replacement rate in the actual construction should be ~50% and should not exceed 75%. Based on the relationship between the compressive strength and splitting strength of ordinary concrete, the relationship model between the unconfined compressive strength and splitting strength of cement–fly-ash-stabilized slag–coal gangue was established. The failure mode, stress–strain curve, peak stress, and failure criterion of these specimens were analyzed based on the triaxial test results, and the relationship formulas between the slag substitution rate, cement content, peak stress, and confining pressure were fitted. As per the SEM results, the mixture’s hydration products primarily included amorphous colloidal C-S-H, needle rod ettringite AFt, unhydrated cement clinker particles, and fly ash particles. The analysis of the mixture’s strength formation mechanism showed that the mixture’s strength was the comprehensive embodiment of all factors, such as the microaggregate effect, secondary hydration reaction, and material characteristics.

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Section: Methodsmentioning

confidence: 99%

Mechanical Properties of Furnace Slag and Coal Gangue Mixtures Stabilized by Cement and Fly Ash

Zhang

Yan

et al. 2021

Materials

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“…A freeze-thaw damage evolution model of coal gangue concrete was developed and analyzed for the development mechanism of freeze-thaw damage of coal gangue concrete. It was shown that with the improvement of the replacement ratio of coal gangue concrete, the relative mass, compressive strength, and relative dynamic elastic modulus decreased rapidly [19]. Therefore, the replacement rate of coal gangue concrete should not be greater than 40% in cold areas, nor should the changes in cumulative water absorption of coal gangue concrete specimens under different replacement rates and the square root of time.…”

Section: Freezing Resistancementioning

confidence: 99%

Using Chinese Coal Gangue as an Ecological Aggregate and Its Modification: A Review

et al. 2022

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Coal gangue is a kind of industrial solid waste with serious ecological and environmental implications. Producing concrete with coal gangue aggregate is one of the green sustainable development requirements. This paper reviews the properties and preparation methods of Chinese gangue aggregate, studies the influence of gangue aggregate on concrete properties and the prediction model of gangue concrete, and summarizes the influence of modified materials on gangue concrete. The studies analyzed in this review show that different treatments influence the performance of coal gangue aggregate concrete. With the increase in the replacement ratio of coal gangue aggregate in concrete, the concrete workability and mechanical performance are reduced. Furthermore, the pore structure changes lead to decreased porosity, greatly affecting the durability. Coal gangue is not recommended for producing high-grade concretes. Nevertheless, pore structure can be improved by adding mineral admixtures, fibers, and admixtures to the coal gangue concrete. Hence, the working properties, mechanical properties, and durability of the concrete can be improved effectively, ensuring that coal gangue concrete meets engineering design requirements. Adding modified materials to coal gangue concrete is a viable future development direction.

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“…The compressive strength of 28d coal gangue aggregate concrete can reach 37 MPa, which meets the strength requirements of C30 ordinary concrete [16]. Qiu et al [17] studied the influence of coal gangue coarse aggregate replacement rate on concrete freeze resistance and established a CGC freeze-thaw damage evolution model. They found that when the coal gangue replacement rate is less than 40%, CGC can better meet the freeze.…”

Section: Introductionmentioning

confidence: 98%

Study on Mechanical Properties of PET Fiber-Reinforced Coal Gangue Fine Aggregate Concrete

Huang

Zhou

2021

Geofluids

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In recent years, with the rapid development of the construction industry, the demand for natural river sand has become increasingly prominent. Development of alternatives to river sand has become an interesting direction for concrete research. In this paper, coal gangue was proposed to replace part of the river sand to produce coal gangue fine aggregate concrete, while waste polyethene terephthalate (PET) bottles were used as raw materials to make PET fibers to improve the mechanical properties of coal gangue fine aggregate concrete. There were two parts of the test conducted. In the first part, the compressive strength of the gangue fine aggregate concrete cube, splitting tensile strength, axial compressive strength, and static elastic modulus were studied when the substitution rate of coal gangue increased from 0% to 50%. Referring to the equation of the full stress-strain curve of plain concrete, the stress-strain constitutive equation of coal gangue fine aggregate concrete was analyzed and studied. By comparing with plain concrete, it was found that the coal gangue concrete with a replacement rate of 50% had higher compressive strength and tensile strength, but its brittleness was significantly greater than that of plain concrete in the later stage. In the second part, by studying the effect of different PET fiber content on the mechanical properties of coal gangue fine aggregate concrete with a replacement rate of 50%, it was found that when the addition of PET fiber was 0.1% and 0.3%, not only were compressive strength, splitting tensile strength, static elastic modulus, and flexural strength of the gangue fine aggregate concrete effectively improved but also the brittleness of concrete can be significantly reduced. The study found that after adding 0.3% PET fiber, the coal gangue fine aggregate concrete with a replacement rate of 50% has better mechanical properties and less brittleness.

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Damage constitutive model of coal gangue concrete under freeze-thaw cycles

Cited by 68 publications

References 13 publications

Mechanical Properties of Furnace Slag and Coal Gangue Mixtures Stabilized by Cement and Fly Ash

Mechanical Properties of Furnace Slag and Coal Gangue Mixtures Stabilized by Cement and Fly Ash

Using Chinese Coal Gangue as an Ecological Aggregate and Its Modification: A Review

Study on Mechanical Properties of PET Fiber-Reinforced Coal Gangue Fine Aggregate Concrete

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