Effect of water addition, plasticizer and alkaline solution constitution on fly ash based geopolymer concrete performance

Aliabdo, Ali A.; Elmoaty, Abd Elmoaty M. Abd; Salem, Hazem A.

doi:10.1016/j.conbuildmat.2016.06.062

Cited by 249 publications

(112 citation statements)

References 18 publications

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“…On the other hand, it can be seen from the reaction process that the water molecules on the left and right sides of the reaction equation are balanced. Therefore, the study [18] believed that water had no role in the chemical reaction except for providing workability. From the reaction equation alone, the content of water does not affect the amount of geopolymer products.…”

Section: Compressive Strengthmentioning

confidence: 99%

“…Weng et al [17] considered that water was the transport medium of aluminosilicate dissolution, ions transfer, tetrahedral compounds hydrolysis, and tetrahedral units polymerization. Aliabdo et al [18] revealed that the addition of water improved the workability of mixture, but reduced other properties of geopolymer concrete. The optimum additional water content was 30 kg/m 3 , which has little effect on properties of geopolymer.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Water Content on Mechanical Strength and Microstructure of Alkali-Activated Fly Ash/GGBFS Mortars Cured at Cold and Polar Regions

Xiang

Feng

et al. 2019

Materials

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Negative temperature curing is a very harmful factor for geopolymer mortar or concrete, which will decrease the strength and durability. The water in the geopolymer mixture may be frozen into ice, and the water content is a crucial factor. The purpose of this paper is to explore the influence of water content on the properties of alkali-activated binders mortar cured at −5 • C. Fly ash (FA) and ground granulated blast furnace slag (GGBFS) were used as binders. Three groups of experiments with different water content were carried out. The prepared samples were investigated through uniaxial compression strength test, Scanning electron microscopy (SEM), and X-ray diffraction (XRD) for the determination of their compressive strength, microstructural features, phase, and composition. The results indicated that, the compressive strength of samples basically maintained 25.78 MPa at an age of 28 days; for 90 days, the values reached 33.4 MPa-34.04 MPa. The results showed that lower water content is beneficial to improving the early strength of mortar at −5 • C curing condition, while it has little impact on long-term strength. These results may provide references for the design and construction of geopolymer concrete in cold regions.However, most previous studies about the alkali-activated fly ash/GGBFS mortar and concrete were carried out by curing samples at elevated temperature or in ambient curing condition [13]. Many researchers believed that addition of GGBFS can significantly improve early and later age mechanical strength of fly ash based geopolymer concrete cured at room temperature [14,15]. Up to now, the research on the physical and mechanical properties of geopolymer concrete curing at negative temperature has not been reported.With the social development, cleaner and energy-saving building materials are needed in cold and polar regions of the world. For example, Figure 1 shows the mean annual air temperature distribution of China in 2015 [16], and the temperature in most areas is lower than 0 • C, however, many infrastructures were built in these areas, such as Qinghai-Tibet railway, Sichuan-Lasa Expressway, and Harbin Dalian high speed railway. These projects only have a very short construction period of positive temperature (above 0 • C) every year, which will extend the entire construction period and increase the cost. If the in-situ casting geopolymer concrete with better performance can be obtained under the condition of negative temperature curing, the construction period will be shortened and the cost will be saved. Materials 2019, 12, x FOR PEER REVIEW 2 of 16building materials, fire-retardant coatings, fiber-reinforced composite materials, and fixed solutions for chemical and nuclear industrial wastes. However, most previous studies about the alkali-activated fly ash/GGBFS mortar and concrete were carried out by curing samples at elevated temperature or in ambient curing condition [13]. Many researchers believed that addition of GGBFS can significantly improve early and later age mechanical strengt...

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Section: Compressive Strengthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of Water Content on Mechanical Strength and Microstructure of Alkali-Activated Fly Ash/GGBFS Mortars Cured at Cold and Polar Regions

Xiang

Feng

et al. 2019

Materials

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“…Geopolymers exhibit good mechanical properties, resistance to high temperatures and chemicals: especially to acids and organic solvents. Geopolymer properties depend on the sort of aluminosilicate, the type of alkali cation (usually Na + or K + ) [4,5], Si/Al molar ratio [6][7][8], the Si/Na molar ratio [9][10][11][12][13][14], water content [15][16][17][18][19] and the curing conditions [17,[20][21][22][23]. Some geopolymer properties can be modified by additives.…”

Section: Introductionmentioning

confidence: 99%

“…Some geopolymer properties can be modified by additives. Geopolymers can be coloured [24], the setting time can be accelerated by calcium ions [25] and the viscosity of the geopolymer binders can be lowered by adding plasticisers [16,26,27]. Geopolymer properties and their variability enable applications in many industrial fields.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Kaolin and Kaolinitic Claystones as Raw Materials for Preparing Meta-Kaolinite-Based Geopolymers

Koutník¹

2019

Ceramics - Silikaty

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Geopolymer binders were then prepared by water addition up to an invariable content of 34 wt. %. The binders were finally mixed with quartz sand in a weight ratio of 40:60. The differences in the properties between the two types of clay materials, the changes in these properties due to dehydration and milling, and the impact of the observed differences on the properties of the geopolymer binders (dynamic viscosity, pore size distribution, colour shade) and filled geopolymers (flexural strength, compressive strength, elastic modulus) were investigated. The kaolinitic claystones had a morphology different from the kaolin, characterised by smaller kaolinite plates, significantly lower pore volumes with average pore diameters and a higher impurities content that caused a more intense colour compared to the kaolin. The above-mentioned differences remained unchanged after thermal and mechanical treatment of the starting clay materials. The geopolymer binders prepared from the calcined and milled kaolinitic claystones were darker in colour and had a significantly lower dynamic viscosity (approximately three times) compared to the geopolymer binders prepared from the kaolin. The dynamic viscosity decreased with the decreasing activator content, while the volume and pore size increased. The mechanical properties of all the prepared geopolymers were excellent (compressive strength >50 MPa, bending strength > 7.9 MPa and elastic modulus >15 GPa) up to a ratio of metakaolinite component/alkali activator of 1:1. Comparison of kaolin and kaolinitic claystones as raw materials for preparing metakaolinite-based geopolymers Ceramics-Silikáty 63 (1) 110-123 (2019)

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“…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.…”

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confidence: 99%

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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Effect of water addition, plasticizer and alkaline solution constitution on fly ash based geopolymer concrete performance

Cited by 249 publications

References 18 publications

Influence of Water Content on Mechanical Strength and Microstructure of Alkali-Activated Fly Ash/GGBFS Mortars Cured at Cold and Polar Regions

Influence of Water Content on Mechanical Strength and Microstructure of Alkali-Activated Fly Ash/GGBFS Mortars Cured at Cold and Polar Regions

Comparison of Kaolin and Kaolinitic Claystones as Raw Materials for Preparing Meta-Kaolinite-Based Geopolymers

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

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