Effect of drying procedures on pore structure and phase evolution of alkali-activated cements

Zhang, Zuhua; Zhu, Yingcan; Zhu, Huajun; Zhang, Yu; Provis, John L.; Wang, Hao

doi:10.1016/j.cemconcomp.2018.12.003

Cited by 117 publications

(24 citation statements)

References 57 publications

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“…The effect of these factors on the water absorption cannot be well established according to the measurements presented in Figure 4, so detailed investigation is required. In addition, high temperatures were used during preconditioning of the specimens, in particular 105 °C and this alter the pore structure of alkaliactivated material and thus give biased results as stated by Zhang et al [48] Control A10 B10 B10M10 A10-SP B10-SP B10M10-SP 0…”

Section: 1mechanical Strengthsmentioning

confidence: 99%

Performance of magnesia-modified sodium carbonate-activated slag/fly ash concrete

Abdalqader

Jin

Al‐Tabbaa

2019

Cement and Concrete Composites

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Various innovative research in the cement industry is looking into improving its environmental sustainability. Sodium carbonate-activated slag/fly ash (NC-SF) binders has recently evolved as a potentially more sustainable binding materials than both Portland cement and conventional alkali activated materials such as sodium silicate and sodium hydroxide activated materials. The reaction mechanism and some microstructural properties of NC-SF cements have been a major area of research recently. However, very few studies have scaled up the investigation of these binders into concrete specimens. This paper, therefore, provides new insight into the strength development and the durability performance of NC-SF concrete and MgO-modified NC-SF concrete. Concrete testing included measurements of compressive strength, split tensile strength, water absorption, depth of carbonation, sulphate exposure, acid exposure and elevated-temperature exposure. Microstructure studies were conducted using Powder X-Ray diffraction (PXRD), Thermogravimetric analysis (TGA) and Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR). It is concluded that NC-SF concrete mixes develop acceptable mechanical strength and demonstrate high resistance to sulphate attack. They also showed higher resistance to acid attack than the control mix based on sodium silicate-activated slag concrete. Here, emphasis is placed on the potential of developing NC-SF concrete with excellent performance and less complicated production methods as well as a low carbon footprint. It is also found that the use of reactive MgO enhanced the strength development of NC-SF concrete as well as its resistance to acid and carbonation.

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Section: 1mechanical Strengthsmentioning

confidence: 99%

Performance of magnesia-modified sodium carbonate-activated slag/fly ash concrete

Abdalqader

Jin

Al‐Tabbaa

2019

Cement and Concrete Composites

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“…On the other hand, because of its advantages like good thermal insulation, light weight, and low cost [4,5], FLA has been widely used in some architectural elds like nonbearing wall construction, bathroom back lling and as functional materials such as thermal insulation material, sound-insulation material, and so on [6,7]. Apart from being used in the traditional building elds, FLA has been applied in di erent areas as a good raw material for the preparation of geopolymer [8][9][10][11][12]. For example, to prove the possibility of in-situ resource utilization of FLA, there are a good many scholars having done plenty of basic studies on this aspect [13][14][15], among which there is one proposing that y ash foamed geopolymer (FAFG) as back lling material can be an excellent combination of y ash consumption and coal mine re prevention [16,17].…”

Section: Introductionmentioning

confidence: 99%

Fly Ash Particle Size Effect on Pore Structure and Strength of Fly Ash Foamed Geopolymer

Xiong

Wan

Zhou

et al. 2019

Advances in Polymer Technology

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e aim of this paper is to study the particle size e ect of y ash (FLA) on pore structure and strength of Fly Ash Foamed Geopolymer (FAFG). Information on the macro-pores such as macro-pore size and distribution of FAFG is captured through binarization processing. Porosity and compressive strength of FAFG are respectively tested by Archimedes density test method and uniaxial compressive strength test method. It can be concluded that the FLA particle size has an e ect on the pore structure and strength of FAFG. More speci cally, the e ect of FLA particle size shows itself macroscopically on the quantity of middle and large macro-pores and the uniformity of macro-pores distribution, and microscopically on the quantity of micro-holes and cracks and calcium silicate (C-S-H) quantity at the early stage of FAFG mixture. All of the properties of FAFG follow some kind of changing rule except at the turning point when FLA particle is of 0.125~0.25 mm in size. To explain clearly the root cause of FLA particle size e ect on FAFG, SEM, and XRD are employed to explore the microstructure of FAFG and the component of FLA. It turns out to be the amorphous phase SiO 2 content in FLA of di erent particle sizes which could determine the reaction extent of FAFG mixture.

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“…The air (water) desorption was performed at 100 o C for typically 24 h. The total pore volume was derived from the amount of vapor adsorbed at a relative pressure close to unity. Surface areas were calculated from the isotherm data using the Brunauer-Emmet-Teller (BET) method [27], while mesopore diameter distributions and cumulative pore volumes were determined through the Barret-Joyner-Halenda (BJH) method [27] using desorption data.…”

Section: Nitrogen Sorption Test (Nst)mentioning

confidence: 99%

The role of calcium stearate on regulating activation to form stable, uniform and flawless reaction products in alkali-activated slag cement

Yang

et al. 2019

Cement and Concrete Composites

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In the course of an investigation on using calcium stearate (CaSt) to improve performance of the alkali-activated slag (AAS) cement, the objective of the present work is to discovery its role in the AAS system. Special interest is devoted to understand the influence of CaSt on the reaction process, reaction products and microstructural features of the AAS cement. To achieve this, isothermal calorimetry, impedance characteristics, infrared spectroscopy, X-ray diffraction, thermogravimetry, nitrogen sorption, mercury intrusion porosimetry and scanning electron microscopy were carried out. According to results obtained, the CaSt has three important effects on the AAS cement. Firstly, it inhibited slag reaction with the activator through decreasing activity of alkalis, whereas the amount of C-(A)-S-H gels in the system depended on the usage of CaSt, because the CaSt could have chemical reactions from the alkali-solution and form similar reaction products. Secondly, there is less sodium and more calcium in reaction products of the CaSt added mix, which improve their stability and uniformity. Finally, microstructure characteristics (e.g. pore size distribution, pore connectivity) are optimised and defects are reduced significantly, when the CaSt is added in the AAS mix.

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Effect of drying procedures on pore structure and phase evolution of alkali-activated cements

Cited by 117 publications

References 57 publications

Performance of magnesia-modified sodium carbonate-activated slag/fly ash concrete

Performance of magnesia-modified sodium carbonate-activated slag/fly ash concrete

Fly Ash Particle Size Effect on Pore Structure and Strength of Fly Ash Foamed Geopolymer

The role of calcium stearate on regulating activation to form stable, uniform and flawless reaction products in alkali-activated slag cement

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