Mechanical Properties and Mechanism Analysis of Graphite Tailings Environment-Friendly Concrete

Duan, Hourui; Liu, Hongbo; Li, Bochen; Wang, Zhongrui; Gao, Hongshuai

doi:10.3390/ma15248870

Cited by 9 publications

(3 citation statements)

References 59 publications

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“…Hu et al [13] used graphite tailings as a raw material to prepare foamed ceramics through the high-temperature self-foaming method, which is also an economic treatment for graphite tailings. However, this is still not enough to satisfy the large utilization of graphite tailings for recycling [14].…”

Section: Introductionmentioning

confidence: 99%

Performance and Heavy Metal Analysis of Graphite Tailings Cured Using Cementitious Materials

Jiang,

Wang

2024

Buildings

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The massive accumulation of graphite tailings causes serious environmental pollution, mainly from heavy metal pollution. Therefore, this article introduces a method of using graphite tailings as a high-content main material, cement as a small component of the auxiliary cementitious material, and clay as a substitute for cement. The compressive strength and permeability of graphite tailing–solidified material (GT, GT–Clay) were tested, and the effect of clay partially replacing cement as an auxiliary cementitious agent on GT–Clay performance was compared. In addition, inductively coupled plasma mass spectrometry (ICP) was used to analyze the effect of the graphite tailing placement time on the heavy metal content, as well as the changes in the GT heavy metal leaching concentration and its heavy metal content under outdoor freeze–thaw conditions. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to elucidate the microstructural changes in the GT–Clay. The experimental results show that, as the substitution of clay for cement increased from 0 to 50%, the compressive strength of the 90% GT–Clay gradually decreased, and the permeability also increased. The compressive strength of 95% GT–Clay did not show significant changes, but the permeability increased, and when mixed with quicklime, gypsum, and silica fume, the permeability decreased. The Ni and As in graphite tailings fluctuated significantly with the placement time. The heavy metal leaching concentrations of the 90% GT and 95% GT were below the standard limit, and Cd, As, and Ni in GT were potential sources of pollution. The analysis of the microscopic test results showed that the hydration products of the GT–Clay included ettringite, Ca(OH)2, and calcium silicate hydrates. The hydration product stabilized and filled the gaps between the tailing particles, thereby cementing them together. Not only did it improve the mechanical strength of GT, it also reduced the permeability and heavy metal leaching rate. This study provides a new analytical approach to applying graphite tailings for environmental treatment.

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Section: Introductionmentioning

confidence: 99%

Performance and Heavy Metal Analysis of Graphite Tailings Cured Using Cementitious Materials

Jiang,

Wang

2024

Buildings

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“…Therefore, it is essential to study the impact of hybrid SF and polyethylene (PE) fiber (PF) on IOT concrete. However, the existing research about IOT concrete mainly focused on f cu , ductility and elastic modulus [36][37][38][39]. Few studies have examined the resistance of hybrid SF and polyethylene (PE) fiber (PF)reinforced IOT concrete to sulfate F-T cycle resistance.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Steel-Polyethylene Fiber-Reinforced Iron Ore Tailing Concrete: Mechanical, Sulfate Freeze–Thaw Resistance, and Microscopic Characteristics

Wang,

2024

Buildings

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This study examines the effects of iron ore tailing (IOT) replacement ratios and the hybridization of steel fiber (SF) and polyethylene (PE) fiber (PF) on the mechanical, sulfate freeze–thaw (F–T) resistance, and microscopic characteristics of IOT concrete. The mechanical properties of specimens including compressive strength (fcu) and splitting tensile strength (fsts) were evaluated. Sulfate F–T cycle indices of specimens including surface damage, fcu loss, relative dynamic elastic modulus (RDEM), and mass loss are examined. Meanwhile, microscopic characteristics are analyzed using industrial computer technology (CT) and scanning electron microscopy (SEM). Results indicated that IOT replacement ratios below 40% positively influenced mechanical properties and sulfate F–T resistance, whereas ratios exceeding 40% exhibited adverse effects. Incorporating hybrid SF and PF further enhanced the mechanical properties and sulfate F–T resistance of IOT concrete. The IOT concrete containing 1.5% SF and 0.6% PF (designated T40S1.5P0.6) demonstrates significantly improved mechanical properties and sulfate F–T resistance. A set of parameters was proposed to predict the fsts. The Weibull damage model, capable of quantitatively reflecting the F–T damage of IOT concrete, was established. The pore structure of IOT concrete gradually deteriorates with increasing sulfate F–T cycles. The pore characteristics of T40S1.5P0.6 were superior. This was further validated through SEM observations.

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“…Wang et al [ 8 ] used graphite tailings to prepare cement mortar and found that graphite tailings, with the optimal addition amount being 20 wt%, can significantly improve the freeze-resistance of cement mortar. In another study, Duan et al [ 9 ] studied the feasibility of completely replacing a concrete sand aggregate with graphite tailings. Their results showed that the mechanical strength of the concrete samples underwent a parabolic change when there was an increase in the replacement rate, and the best replacement rate was 30%.…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of Iron-Tailings-Based Cementitious Mortars with Incorporated Graphite Ore and Graphite Tailings: Strength Properties and Microstructure

et al. 2023

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Graphite ore and graphite tailings were blended into iron-tailings-based cementitious mortars, and their mechanical properties and microstructure were experimentally investigated. The flexural and compressive strengths of the resulting material were tested to compare the effects of graphite ore and graphite tailings as supplementary cementitious materials and fine aggregates on the mechanical properties of iron-tailings-based cementitious mortars. Additionally, their microstructure and hydration products were mainly analyzed using scanning electronic microscope and X-ray powder diffraction techniques. The experimental results showed that the mechanical properties of the mortar material incorporating graphite ore were reduced due to the lubricating properties of graphite ore. As a result, the unhydrated particles and aggregates were not tightly bound to the gel phase, making the direct application of graphite ore in construction materials unfeasible. In the iron-tailings-based cementitious mortars prepared in this work, the optimal incorporation rate of graphite ore as a supplementary cementitious material was 4 wt%. The compressive strength of the optimal mortar test block after 28 days of hydration was 23.21 MPa, and the flexural strength was 7.76 MPa. The mechanical properties of the mortar block were found to be optimal with a graphite-tailings content of 40 wt% and an iron-tailings content of 10 wt%, resulting in a 28-day compressive strength of 48.8 MPa and a flexural strength of 11.7 MPa. By observing the microstructure and XRD pattern of the 28-day hydrated mortar block, it was determined that the hydration products of the mortar with graphite tailings as an aggregate included ettringite, Ca(OH)2, and C-A-S-H gel.

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Mechanical Properties and Mechanism Analysis of Graphite Tailings Environment-Friendly Concrete

Cited by 9 publications

References 59 publications

Performance and Heavy Metal Analysis of Graphite Tailings Cured Using Cementitious Materials

Performance and Heavy Metal Analysis of Graphite Tailings Cured Using Cementitious Materials

Hybrid Steel-Polyethylene Fiber-Reinforced Iron Ore Tailing Concrete: Mechanical, Sulfate Freeze–Thaw Resistance, and Microscopic Characteristics

Comparative Study of Iron-Tailings-Based Cementitious Mortars with Incorporated Graphite Ore and Graphite Tailings: Strength Properties and Microstructure

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