Investigation of the hydration kinetics and microstructure formation mechanism of fresh fly ash cemented filling materials based on hydration heat and volume resistivity characteristics

Yin, Bo; Kang, Tianhe; Kang, Jianting; Chen, Yuejuan; Wu, Linlin; Du, Mingze

doi:10.1016/j.clay.2018.09.019

Cited by 54 publications

(20 citation statements)

References 45 publications

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“…As concluded by Yang et al 18 and Jin et al 13 , the mechanical grinding was beneficial to improve the amorphous phase content and produce more lattice distortion and defects in the physical structure, which would decrease the diffraction intensities of the materials. findings reported by others 43,44 . Note that a strong exothermic peak occurs within the first 1-2 hours when cement contacts with water.…”

Section: Resultssupporting

confidence: 60%

Effects of Fineness and Content of Phosphorus Slag on Cement Hydration, Permeability, Pore Structure and Fractal Dimension of Concrete

et al. 2021

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The utilization of phosphorus slag (PHS) to replace the fly ash in the construction of hydraulic projects has attracted a growing attention in China. In this study, the influence of PHS fineness and content on cement hydration, mechanical strength, permeability as well as the pore structure and fractal dimension (Ds) of concrete have been discussed. The results indicate that the PHS addition retards the cement hydration and hence decreases the hydration heat within 3 days. The incorporation of PHS with a Blaine specific surface area of 505 m 2 /kg (PHS) could participate in the early pozzolanic reaction and consequently offsets the retarding effect to some extent. The incorporation of 20-40 w% PHS declines the early strength of concrete, but this reduction effect on strength can be eliminated to some degrees by mechanically grinding the PHS. The compressive strengths of concrete added with PHS with a high fineness of 505 m 2 /kg

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Section: Resultssupporting

confidence: 60%

Effects of Fineness and Content of Phosphorus Slag on Cement Hydration, Permeability, Pore Structure and Fractal Dimension of Concrete

et al. 2021

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“…Specifically, FC35 concrete exhibits a porosity of 40.8 % and the most probable aperture of 286 nm at 3 days, which are about 5.1 % and 75 nm larger compared with those of C35 concrete, respectively. This can be explained by the dilution effect of fly ash and its almost inert nature at early age 3,21,22 . By contrast, the porosity and the most probable aperture are decreased from 31.6 % and 64 nm in C35 concrete to 24.6 % and 59.0 nm in FC35 concrete at 28 days,…”

Section: Mip Resultsmentioning

confidence: 99%

“…respectively, which are decreased by 16 % and 11 % compared with those of C35 one (1.91 MPa and 3.50 MPa). The reduction in early-and middle-age strengths is mainly due to the dilution effect (the cement is partially substituted by fly ash) and the low reactivity of fly ash at early age 3,21,22 . On the contrary, Fig.…”

Section: Compressive and Splitting Tensile Strengthmentioning

confidence: 99%

“…Fly ash is a by-product of the coal power plants, which consists mostly of SiO2 and Al2O3 within the alumino-silicate glassy phases and also small amount of crystalline constituents such as quartz and mullite 18,19 . Due to its dilution effect and almost inert nature at early age, fly ash can decrease the shrinkage and internal temperature rising and improve the durability of concrete [20][21][22] . As a result, fly ash is widely used in hydraulic mass concrete to reduce or prevent the early cracking risk 3,6,12 .…”

Section: Introductionmentioning

confidence: 99%

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Pore Structural and Fractal Analysis of the Influence of Fly Ash and Silica Fume on the Mechanical Property and Abrasion Resistance of Concrete

et al. 2021

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Dam concrete suffers from serious abrasion damages in southwestern China, the abrasion resistance of concrete is therefore one of the most important factors determining the reliability even the safety of the dams. In the present work, the effects of fly and/or silica fume on the mechanical properties, drying shrinkage, as well the cracking and abrasion resistance of concrete were investigated, then the pore structures of concrete added with fly ash and silica fume and the pore surface fractal dimensions (Ds) were determined by the mercury intrusion porosimetry (MIP) method and a fractal model, respectively. Finally, the relationships between the abrasion resistance of concrete and the porosity as well as the Ds were revealed and discussed. The results indicate that silica fume significantly increases the drying shrinkage especially at early age, while the incorporation of fly ash and silica fume together can decease the early plastic shrinkage-induced cracking risk and the final shrinkage to some degrees. Besides, the utilization of 5 wt% silica fume and 20 wt% fly ash together increases the abrasion resistance and mechanical property by about 4-9 % at various ages. In addition, the compressive strength and the abrasion resistance of concrete are linearly correlated with the concrete porosity and the Ds. Both the fly ash and silica fume could decrease the porosity of concrete and increase the Ds, therefore the concrete containing fly ash

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“…This corresponds well with the findings in many other authors 14,59 , who reported that the addition of SRA decreased the alkalinity of the pore solution in concrete and thus directly inhibiting the cement hydration to some extent, which adversely affected the strength development of concrete. -6 ), which can be also explained by the dilution effect of fly ash and its weak reactivity at early age [49][50][51] .…”

Section: Fractal Model Of Pore Structurementioning

confidence: 99%

Comparison of Fly Ash, Pva Fiber, Mgo and Shrinkage-Reducing Admixture on the Frost Resistance of Face Slab Concrete via Pore Structural and Fractal Analysis

et al. 2021

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Face slab concrete suffers from serious frost damage in cold regions in China, how to improve the frost resistance of face slab concrete in cold regions is one of the important issues in concrete faced rockfill dam (CFRD) design and construction. The results in this paper indicate that the frost resistance of concrete can be improved by adding fly ash, fiber, MgO and shrinkage-reducing admixtures (SRA), and the efficiency is in the sequence: (fly ash + fiber) > fiber > fly ash > MgO > SRA. The incorporation of 0.8 kg/m 3 PVA fiber and 20 wt% fly ash together enhances the compressive strength and tensile capacity of concrete by 6-7 % at late age, whereas the addition of 6 wt% MgO or 1 wt% SRA reduces the compressive strength and tensile capacity by about 4-10 % at various ages. The Ds of concrete added with fly ash, fiber, MgO and SRA is within the range of 2.619-2.796. The frost resistance of concrete correlates linearly with the air void parameters, pore structures and Ds. The utilization of fly ash and/or PVA fiber refines and optimizes the pore structure, thus increasing Ds and improving the frost resistance. On the contrary, MgO and SRA in this study are less effective in refining the pores than PVA fiber and fly ash, thereby producing smaller Ds and relatively weaker frost resistance.

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Investigation of the hydration kinetics and microstructure formation mechanism of fresh fly ash cemented filling materials based on hydration heat and volume resistivity characteristics

Cited by 54 publications

References 45 publications

Effects of Fineness and Content of Phosphorus Slag on Cement Hydration, Permeability, Pore Structure and Fractal Dimension of Concrete

Effects of Fineness and Content of Phosphorus Slag on Cement Hydration, Permeability, Pore Structure and Fractal Dimension of Concrete

Pore Structural and Fractal Analysis of the Influence of Fly Ash and Silica Fume on the Mechanical Property and Abrasion Resistance of Concrete

Comparison of Fly Ash, Pva Fiber, Mgo and Shrinkage-Reducing Admixture on the Frost Resistance of Face Slab Concrete via Pore Structural and Fractal Analysis

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