Influence of fly ash on the pore structure and shrinkage characteristics of metakaolin-based geopolymer pastes and mortars

Yang, Tao; Zhu, Huajun; Zhang, Zuhua

doi:10.1016/j.conbuildmat.2017.05.067

Cited by 173 publications

(66 citation statements)

References 42 publications

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“…Combining the results of Figures 6 and 7, it was found that both the drying shrinkage and water retention showed the significant and almost similar change trend in the first 14 d, indicating water fragment escape strongly effected the shrinkage behavior of AAM coating. For these results, it may be explained that the low water fragment removal reduced tension stress in capillary pores and volume change degree of coating [19]. On the other hand, it also may be explained that the improvement of toughness resulted from the filling effect of CMS organic polymer [30].…”

Section: Water Retention Shrinkage and Crackingmentioning

confidence: 96%

“…On the other hand, it also may be explained that the improvement of toughness resulted from the filling effect of CMS organic polymer [30]. Large shrinkage behavior of AAM definitely led to volume change and subsequently caused cracking [19]. The coatings appearance after being 28 d cured in the ambient environment ( Figure 8) indicated that CMS significantly reduced the risk of cracking.…”

Section: Water Retention Shrinkage and Crackingmentioning

confidence: 99%

“…Thus, the application of alkali-activated slag presents outstanding advantage in simple manufacture process, low-price, easy accessibility of raw materials, energy conservation, low-carbon emission, etc. AAM binders have nanostructural amorphous or poorly-crystalline gel of N-A-S(-H)/C-(N)-A-S-H, which results in outstanding characteristics in high early mechanical strength, excellent physical-chemical stability, great corrosion resistance, good workability, and adhesive strength between different materials [9,[16][17][18][19]. Moreover, compared to the smooth thin film produced by the traditional coatings, fresh AAM is a slurry-like which easily realizes the desired artistic shape as the coating layer is thicker.…”

mentioning

confidence: 99%

“…This issue can be overcome by compositing organic modifiers, using entangled organic molecular long chains to fill or intertwine between particle gaps so as to improve cohesiveness. Unfortunately, many studies have found that organic modifiers' molecular structure or their functional groups will be destroyed in high alkalinity due to the poor chemical compatibility problem [19,24]. It is still, to this day, a challenge to find useful organic modifiers or a simple method by which to effectively change AAM visco-elastic behavior so that it meets engineering requirements.The objective of this paper was to develop a one-part plastic formable AAM coating for building decorating by using starch (CMS) organic/inorganic hybrid composite.…”

mentioning

confidence: 99%

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One-Part Plastic Formable Inorganic Coating Obtain from Alkali-Activated Slag /Starch(CMS) Hybrid Composites

Qin

Lin

et al. 2020

Molecules

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Coating technology can be applied to decorate building constructions. Alkali-activated materials (AAM) are promising green and durable inorganic binders which show potential for development as innovative coating. In the paper, the possibility of using AAM composited with starch (CMS) as a novel plastic formable inorganic coating for decorating in building was investigated. The rheological properties, including plastic viscosity, yield stress, and thixotropy were considered to be critical properties to obtain the working requirements. Four different mixtures were systematically investigated to obtain the optimum formulation, and then were used to study their hardened properties, such as mechanical strengths (compressive, flexural, and adhesive strength), drying shrinkage, cracking behavior, and microstructure. Study results found that CMS could quickly and efficiently be hydrolyzed in an alkaline solution to produce organic plastic gel which filled in AAM paste, leading to the significant improvement of coating consistency, plastic viscosity, and thixotropy. The optimum coating composited with 15.40 wt% CMS shows a relatively stable rheological development, the setting time sufficient at higher than 4 h. Furthermore, CMS shows a significant positive effect on the cracking and shrinkage control due to padding effect and water retention of CMS, which results in no visible cracks on the coating surface. Although the mechanical strength development is relatively lower than that of plain AAM, its value, adhesive strength 2.11 MPa, compressive strength 55.09 MPa, and flexural strength 8.06 MPa highly meet the requirements of a relevant standard.

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Section: Water Retention Shrinkage and Crackingmentioning

confidence: 96%

Section: Water Retention Shrinkage and Crackingmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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One-Part Plastic Formable Inorganic Coating Obtain from Alkali-Activated Slag /Starch(CMS) Hybrid Composites

Qin

Lin

et al. 2020

Molecules

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“…Now the research contents mainly focus on the effect of fly ash activators kind and quantity and curing process on the material properties, as well as the aggregation mechanism of key ion clusters AlO 4 and SiO 4 . Great progresses have been made in this field [22]. However, the higher cost of this product comparing to the cement product has not solved yet.…”

Section: Geopolymer Production the Name Of Geopolymer Was First Prmentioning

confidence: 99%

Challenges and Developments in the Utilization of Fly Ash in China

Ma¹,

Xu²,

Qiqige³

et al. 2017

IJESD

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Abstract-China's coal-fired power plants produce about 600 million tons fly ash annually, which has caused severe economic and environmental problems. This paper first describes briefly the production and utilization status of coal fly ash in China. Then it analyzes the main challenges to the fly ash utilization in China due to the conflict between the huge amount production of fly ash and the depressed consumption of fly ash, as well as the increasing driving forces in the environmental protection. Subsequently, the new developments of fly ash utilization in China, including valuable elements extraction, geopolymer production, fly ash-based ceramics synthesis and soil desertification control are introduced in detail.

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Effect of geogrid reinforcement on the drying shrinkage and thermal expansion of geopolymer concrete

Al-Hedad

Farhan

Zhang

et al. 2019

Structural Concrete

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2019 fib. International Federation for Structural Concrete The effect of triaxial geogrid reinforcement on the thermal expansion and drying shrinkage of geopolymer concrete (GPC) was experimentally investigated. Three groups of GPC prism specimens with a length of 280 mm and a cross-section of 75 mm x 75 mm were prepared and tested in this study. The first group included six unreinforced GPC specimens and was considered as the control group of specimens. The second group included six GPC specimens reinforced with one layer of geogrid. The third group included six GPC specimens reinforced with two layers of geogrid. The triaxial geogrid reinforcement was placed at a depth of 37.5 mm from the surface of the specimen. The tests were carried out by drying the GPC specimens in a controlled environmental chamber at a temperature of 27 ± 4°C and a relative humidity of 50 ± 10% for 98 days. It was found that the geogrid significantly reduced the thermal expansion and drying shrinkage of GPC specimens. The thermal expansion and drying shrinkage were less in the GPC specimens reinforced with two layers of geogrid compared to the GPC specimens reinforced with one layer of geogrid. It was also found that the rate of thermal expansion and drying shrinkage of the GPC specimens reinforced with geogrid was lower than that of the control unreinforced GPC specimens.

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Influence of fly ash on the pore structure and shrinkage characteristics of metakaolin-based geopolymer pastes and mortars

Cited by 173 publications

References 42 publications

One-Part Plastic Formable Inorganic Coating Obtain from Alkali-Activated Slag /Starch(CMS) Hybrid Composites

One-Part Plastic Formable Inorganic Coating Obtain from Alkali-Activated Slag /Starch(CMS) Hybrid Composites

Challenges and Developments in the Utilization of Fly Ash in China

Effect of geogrid reinforcement on the drying shrinkage and thermal expansion of geopolymer concrete

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