Effect of Silicate Content on the Properties of Alkali-Activated Blast Furnace Slag Paste

Qureshi, Mohammed Nadeem; Ghosh, Somnath

doi:10.1007/s13369-014-1172-x

Cited by 29 publications

(7 citation statements)

References 28 publications

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“…There is a sharp decrease in the porosity, when the silica content is increased by modification of sodium silicate modulus (Na4.3Si15-17). Similar result were reported by other researchers [50]. However, it was observed an increase in porosity when DE is increased (Na4.3Si20 and Na4.3Si22).…”

Section: Water Absorption and Porositysupporting

confidence: 91%

Alkali Activation of Ladle Slag from Steel-Making Process

Adesanya

Ohenoja

Kinnunen

et al. 2016

J. Sustain. Metall.

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Section: Water Absorption and Porositysupporting

confidence: 91%

Alkali Activation of Ladle Slag from Steel-Making Process

Adesanya

Ohenoja

Kinnunen

et al. 2016

J. Sustain. Metall.

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“…In general, the coexistence of C-A-S-H and N-A-S-H gels in FA/GBFS concrete explains the positive behavior of this material. The best characteristics presented by GBFS/OPC and FA/GBFS are related to the greater densification and compactness observed in the SEM test, and due to the lower number of capillaries or permeable pores present in this type of alkaline-activated materials (Valencia-Saavedra et al, 2018;Chotetanorm et al, 2013;Qureshi and Ghosh, 2014;Aydin and Baradan, 2014). Figure 5 shows the results of the rapid chloride permeability test, performed on OPC, GBFS/OPC, and FA/GBFS concretes after 28 days of curing, based on the procedure described in ASTM C1202 (ASTM International, 2019a).…”

Section: Resultsmentioning

confidence: 95%

Alkali-activated concretes based on fly ash and blast furnace slag: Compressive strength, water absorption and chloride permeability

2020

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Concretes based on alkaliactivated binders have attracted considerable attention as new alternative construction materials, which can substitute Portland Cement (OPC) in several applications. These binders are obtained through the chemical reaction between an alkaline activator and reactive aluminosilicate materials, also named precursors. Commonly used precursors are fly ash (FA), blast furnace slag (GBFS), and metakaolin. The present study evaluated properties such as compressive strength, rate of water absorption (sorptivity), and chloride permeability in two types of alkaliactivated concretes (AAC): FA/GBFS 80/20 and GBFS/OPC 80/20. OPC and GBFS/OPC* concretes without alkaliactivation were used as reference materials. The highest compressive strength was observed in the FA/GBFS concrete, which reported 26,1% greater strength compared to OPC concrete after 28 days of curing. The compressive strength of alkaliactivated FA/GBFS 80/20 and GBFS/OPC 80/20 was 61 MPa and 42 MPa at 360 days of curing, respectively. These AAC showed low permeability to the chloride ion and a reduced water absorption. It is concluded that these materials have suitable properties for various applications in the construction sector.

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“…The Na 2 O content had a clear effect on drying shrinkage: a high Na 2 O content led to low drying shrinkage. As result of low Na 2 O content with low OH - ions concentration, the paste could not complete hydration reaction and residual moisture evaporation led to high drying shrinkage [ 24 ]. Meng Wu et al [ 25 ] also suggested that amorphous gels lost moisture caused greater drying shrinkage.…”

Section: Resultsmentioning

confidence: 99%

Mitigating the Drying Shrinkage and Autogenous Shrinkage of Alkali-Activated Slag by NaAlO2

2020

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The shrinkage of alkali-activated slag (AAS) is obviously higher than ordinary Portland cement, which limited its application in engineering. In this study, the effects of NaAlO2 in mitigating drying shrinkage and autogenous shrinkage of AAS were studied. To further understand the shrinkage mechanism, the hydration products and microstructures were studied by X-ray diffraction, scanning electron microscopy and nitrogen adsorption approaches. As the partial substitution rate of NaAlO2 for Na2SiO3 increased, the drying shrinkage and autogenous shrinkage reduced significantly. The addition of NaAlO2 could slow down the rate of hydration reaction and reduce the porosity, change the pore diameter and the composition of generated paste and cause more hydrotalcite and tetranatrolite generated—which contributed to reduced shrinkage. Additionally, raising the Na2O content rate caused obvious differences in drying shrinkage and autogenous shrinkage. As the Na2O content elevated, the drying shrinkage decreased and autogenous shrinkage increased. A high Na2O content would cause complete hydration reactions and provoke high autogenous shrinkage. However, incomplete hydration reactions left more water in the paste, and the evaporated water dramatically influenced drying shrinkage. The results indicate that addition of NaAlO2 could greatly mitigate the drying shrinkage and autogenous shrinkage of AAS.

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Effect of Silicate Content on the Properties of Alkali-Activated Blast Furnace Slag Paste

Cited by 29 publications

References 28 publications

Alkali Activation of Ladle Slag from Steel-Making Process

Alkali Activation of Ladle Slag from Steel-Making Process

Alkali-activated concretes based on fly ash and blast furnace slag: Compressive strength, water absorption and chloride permeability

Mitigating the Drying Shrinkage and Autogenous Shrinkage of Alkali-Activated Slag by NaAlO2

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