Experimental study on the effect of fly ash with ammonium salt content on the properties of cemented paste backfill

Tang, Renlong; Zhao, Baosheng; Li, Chao; Xin, Jie; Xu, Baowa; Tian, Chuang; Ning, Jianbo; Li, Longqing; Shao, Xiaoping

doi:10.1016/j.conbuildmat.2023.130513

Cited by 20 publications

(4 citation statements)

References 67 publications

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“…Zhang and Tang et al [ 55 ] reached similar conclusions. For example, Tang et al [ 83 ] studied fly ash–aeolian sand filling materials and found that AFt and C-(A)-S-H gels in the samples increased with the extension of curing age, and the micro-morphology of the samples changed from loose to dense.…”

Section: Resultsmentioning

confidence: 99%

Preliminary Study of Preheated Decarburized Activated Coal Gangue-Based Cemented Paste Backfill Material

et al. 2023

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This study proposes a novel idea of the use of coal gangue (CG) activation and preheated decarburized activated coal CG-based cemented paste backfill material (PCCPB) to realize green mining. PCCPB was prepared with preheated decarburized coal CG (PCG), FA, activator, low-dose cement, and water. This idea realized scale disposal and resource utilization of coal CG solid waste. Decarbonization and activation of CG crushed the material to less than 8 mm by preheated combustion technology at a combustion temperature of 900 °C and a decarbonization activation time of 4 min. The mechanism of the effect of different Na2SO4 dosages on the performance of PCCPB was investigated using comprehensive tests (including mechanical property tests, microscopic tests, and leaching toxicity tests). The results show that the uniaxial compressive strength (UCS) of C-S2, C-S3, and C-S4 can meet the requirements of backfill mining, among which the UCS of C-S3 with a curing time of 3 d and 28 d were 0.545 MPa and 4.312 MPa, respectively. Na2SO4 excites PCCPB at different curing time, and the UCS of PCCPB increases and then decreases with the increase in Na2SO4 dosage, and 3% of Na2SO4 had the best excitation effect on the late strength (28 d) of PCCPB. All groups’ (control and CS1-CS4 groups) leachate heavy metal ions met the requirements of groundwater class III standard, and PCCPB had a positive effect on the stabilization/coagulation of heavy metal ions (Mn, Zn, As, Cd, Hg, Pb, Cr, Ba, Se, Mo, and Co). Finally, the microstructure of PCCPB was analyzed using FTIR, TG/DTG, XRD, and SEM. The research is of great significance to promote the resource utilization of coal CG residual carbon and realize the sustainable consumption of coal CG activation on a large scale.

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Section: Resultsmentioning

confidence: 99%

Preliminary Study of Preheated Decarburized Activated Coal Gangue-Based Cemented Paste Backfill Material

et al. 2023

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“…The AN content observed in AS displays a consistent downward trend as the quantity of CG decrease. Ammonium salts present in FA [46] have the ability to be quickly released into AN within the AS, hence aiding in the stabilization of AN when exposed to alkaline The primary composition of DG consists of CaCO 3 , a mineral that is soluble in water. The addition of DG to the soil results in the hydrolysis of Ca 2+ and SO4 2− , leading to enhancements in soil structure and permeability [22,45].…”

Section: As Nutrient Analysismentioning

confidence: 99%

Section: As Nutrient Analysismentioning

confidence: 99%

Physicochemical Properties and Planting Performance of Artificial Soil Developed from Multiple Coal-Based Solid Waste Materials

Shu,

Wang,

2024

Sustainability

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Using coal-based solid waste (CSWM) to develop artificial soil (AS) can solve the shortage of planting soil in mine ecological restoration and realize the resource utilization of solid waste, which is a very promising research direction. This study used three common CSWM, coal gangue (CG), fly ash (FA), and desulfurization gypsum (DG), to prepare AS. The physicochemical properties of AS, such as bulk density, specific gravity, porosity, field water capacity, available nutrient content, pH value and EC value, were studied. Simultaneously, Elymus dahuricus was utilized in pot experiments to explore the planting performance of AS. Results show that, as the CG content decreased, the specific gravity of AS decreased, and the porosity increased. Both field capacity and saturation capacity demonstrated a notable upward trend. The results of pot experiments showed that plant growth was best when the CG content in AS was 80% and the FA and DG content was 20%. In comparison to the control group consisting of pure CG, the plant biomass in the optimal experimental group exhibited a significant increase of 20.48%. This study verified the feasibility of making AS by combining various CSWM, and provides a new pathway for ecological restoration and resource utilization in mines.

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“…It should also be noted that concretes made with the participation of SCMs allow not only to reduce CO 2 emissions generated during the burning of the Portland clinker [44,45], but also significantly reduce the amount of energy necessary to carry out this technological process [46]. The broad group of SCMs includes both traditional mineral additives such as: fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBFS) , metakaolin (MK) [47][48][49][50][51][52][53], volcanic pumice powder [54], or eggshells [55] as well as nanoadditives, which have been used to a large extent for several years [56][57][58][59][60][61][62][63][64][65]. Moreover, municipal sewage sludge are also used [66,67].…”

Section: Introductionmentioning

confidence: 99%

Examination of water absorption of low volume fly ash concrete (LVFAC) under water immersion conditions

Golewski

2023

Mater. Res. Express

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The studies were carried out to find a relation between important physical property and the main mechanical parameter of concretes containing fly ash (FA) in order to develop indications for the production of durable composites with the addition of this waste. The tests included low volume fly ash concrete (LVFAC). The cements used in the studies were following: ordinary Portland cement (OPC), (FA-00) and two blended Portland cements containing FA in the amount of: 20%, (FA-20) and 30% (FA-30). Measurements of water adsorption (wa) by immersion and compressive strength (fcm) of analysed composites have been performed. The methodology of the wa tests was to reflect the conditions prevailing in the case of concrete- and reinforced concrete structures operating below the water table. The microstructure of all three materials was also assessed. Test results indicated that LVFAC mixes developed 28-day fcm between 45.10 for FA-30 to 48.96 MPa for FA-20 with a value of 47.51 MPa for the reference concrete. Neverless wa of LVFAC mixes decreased with the increase in FA content. The average values of wa was 4.6% for FA-30 and 5.3% for FA-20, respectively, while for concrete without FA it was 5.0%. Thus, it was found that wa by immersion was inversely proportional to the fcm. Based on the microstructural studies it was found that this behavior is attributed to reduced pore diameters and densification of cement matrix microstructure in FA-30 concrete. On the other hand concrete of series FA-20 showed a loose and porous microstructure, and wa in this composite increased accordingly. It can be stated that, the LVFAC containing 30% FA may increase durability of reinforced concrete structures subjected to immersion conditions.

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Experimental study on the effect of fly ash with ammonium salt content on the properties of cemented paste backfill

Cited by 20 publications

References 67 publications

Preliminary Study of Preheated Decarburized Activated Coal Gangue-Based Cemented Paste Backfill Material

Preliminary Study of Preheated Decarburized Activated Coal Gangue-Based Cemented Paste Backfill Material

Physicochemical Properties and Planting Performance of Artificial Soil Developed from Multiple Coal-Based Solid Waste Materials

Examination of water absorption of low volume fly ash concrete (LVFAC) under water immersion conditions

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