Influence of the Variability of Calcareous Fly Ash Properties on Rheological Properties of Fresh Mortar with Its Addition

Nowoświat, Artur; Gołaszewski, Jacek

doi:10.3390/ma12121942

Cited by 22 publications

(17 citation statements)

References 15 publications

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“…The chemical components of FA and GGBFS are shown in Table 1, which were determined by a Bruker S8 TIGER Series 2 X-ray fluorescence (XRF, Bruker Corporation, Karlsruhe, Germany) apparatus. The chemical component of FA is vital important to the test results [22]. Moreover, Figure 3 exhibited XRD patterns of the FA and GGBFS, respectively, which were conducted on a Bruker D8 ADVANCE apparatus.…”

Section: Raw Materialsmentioning

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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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: Raw Materialsmentioning

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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“…The chemical and mineral composition of BBA is appropriate for reusing in the production of new, low-carbon building materials. In this way, the replacement of traditional initial material [3,4] such as fly ash or slag in alkali activated materials (AAM) by BBA leads to important environmental benefits [5][6][7]. As demand for ecological alternatives to Portland cement like alkali 2 of 13 activated materials (AAM) is growing, there is interest to utilize phosphogypsum (PG) in AAM.…”

Section: Introductionmentioning

confidence: 99%

Alkali Activated Paste and Concrete Based on of Biomass Bottom Ash with Phosphogypsum

et al. 2020

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There is a growing interest in the development of new cementitious binders for building construction activities. In this study, biomass bottom ash (BBA) was used as aluminosilicate precursor and phosphogypsum (PG) was used as a calcium source. The mixtures of BBA and PG were activated with the sodium hydroxide solution or the mixture of sodium hydroxide solution and sodium silicate hydrate solution. Alkali activated binders were investigated using X-ray powder diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM) test methods. The compressive strength of hardened paste and fine-grained concrete was also evaluated. After 28 days, the highest compressive strength reached 30.0 MPa—when the BBA was substituted with 15% PG and activated with NaOH solution—which is 14 MPa more than control sample. In addition, BBA fine-grained concrete samples based on BBA with 15% PG substitute activated with NaOH/Na2SiO3 solution showed higher compressive strength compered to when NaOH activator was used −15.4 MPa and 12.9 MPa respectfully. The NaOH/Na2SiO3 activator solution resulted reduced open porosity, so potentially the fine-grained concrete resistance to freeze and thaw increased.

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“…The greater or lesser pozzolans reactivity on portlandite (Ca(OH) 2 ), depends primarily on their amorphism, state, and reactive nature of their structure [ 3 , 4 , 5 , 6 ]. The cement industry has also gradually evolved toward the gradual inclusion, along with pozzolans, of crystalline mineral additions known as fillers, some of which interact physically and/or chemically with Portland cement [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

Portland Cements with High Content of Calcined Clay: Mechanical Strength Behaviour and Sulfate Durability

Aramburo¹,

Pedrajas

Talero³

2020

Materials

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Calcined clay has become the supplementary cementitious materials with the greatest potential to reduce the clinker/cement. In this research, the mechanical strengths and sulphate resistance of blended cements with a high content of calcined clay as a pozzolanic addition were evaluated to demonstrate that these cements could be designed as CEM (cement) type IV/A-SR and IV/B-SR cements by the current European standard UNE-EN 197-1: 2011. The blended cements were prepared by two Portland cements (P1 and PY6) with different mineralogical compositions and a calcined clay. The level of replacement was greater than 40% by weight. The results obtained confirm the decrease in the mechanical strengths and the increase in the sulfate resistance of the two Portland cements when they are replaced by calcined clay at a level of replacement greater than 40%. These results are a consequence of the chemical effect from the pozzolanic activity of the calcined clay. Therefore, there is an important decrease in portlandite levels of paste liquid phase that causes the increase in sulfate resistance and the decrease of the mechanical strengths.

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Influence of the Variability of Calcareous Fly Ash Properties on Rheological Properties of Fresh Mortar with Its Addition

Cited by 22 publications

References 15 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

Alkali Activated Paste and Concrete Based on of Biomass Bottom Ash with Phosphogypsum

Portland Cements with High Content of Calcined Clay: Mechanical Strength Behaviour and Sulfate Durability

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