Workability and Setting Time of Alkali Activated Blast Furnace Slag Paste

Qureshi, Mohd. Nadeem; Ghosh, Somnath

doi:10.1520/acem20120029

Cited by 9 publications

(4 citation statements)

References 9 publications

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“…Both effects were observed also by others and were related to a higher pH values which accelerated dissolution of the slag [24,27,[35][36][37]. Higher alkali modulus of the used SS activator decreased the compressive strength values in both slags (Figure 9).…”

Section: K B Hmsupporting

confidence: 69%

Geopolymer Based on Mechanically Activated Air-cooled Blast Furnace Slag

et al. 2020

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An efficient solution to increase the sustainability of building materials is to replace Portland cement with alkali-activated materials (AAM). Precursors for those systems are often based on water-cooled ground granulated blast furnace slags (GGBFS). Quenching of blast furnace slag can be done also by air but in that case, the final product is crystalline and with a very low reactivity. The present study aimed to evaluate the cementitious properties of a mechanically activated (MCA) air-cooled blast furnace slag (ACBFS) used as a precursor in sodium silicate alkali-activated systems. The unreactive ACBFS was processed in a planetary ball mill and its cementing performances were compared with an alkali-activated water-cooled GGBFS. Mixes based on mechanically activated ACBFS reached the 7-days compressive strength of 35 MPa and the 28-days compressive strength 45 MPa. The GGBFS-based samples showed generally higher compressive strength values.

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Section: K B Hmsupporting

confidence: 69%

Geopolymer Based on Mechanically Activated Air-cooled Blast Furnace Slag

et al. 2020

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“…The condensation process in the dissolution of geopolymer follows two stages; one is fast while another is slow 3 3 . Again, the degree of aluminosilicate polymerization depends on the concentration of silicate solution 34,35 . E. Prud'homme et al confirm the existence of "in situ inorganic foam" in the presence of silica fume as an ENHANCING THE MECHANICAL AND MICRO-STRUCTURAL Dutta and Ghosh external agent in TGA-MS 25,26 .…”

Section: Effect Of Supplements On Silicate Modulusmentioning

confidence: 99%

Enhancing the Mechanical and Microstructural Properties of Silica Fume Blended Fly Ash Based Geopolymer Using Murram as a Tertiary Supplement

Dutta¹,

Ghosh²

2018

RJC

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The present study aims to investigate the compressive strength and the underlying micro-structural change of fly ash geopolymer paste with silica fume and murram as supplements up to 10% and 2.5% of the total weight respectively. The workability property of the geopolymer paste samples was evaluated at a green state using a unique methodology based on the polar graph. Besides, various geopolymer paste samples were subjected to heat curing at different temperatures and also for different durations to find the influence of heat curing to the obtained compressive strengths. The present study also probed into the underlying micro-structural changes of the corresponding geopolymer paste samples through SEM (Scanning Electron Microscopy), MIP (Mercury Intrusion Porosimetry) and EDX (Energy Dispersive X-Ray Analysis). Through the present analysis, it can be concluded that blending of silica fume and murram with fly ash based geopolymer paste results in a sustainable high performance binder even at lower alkalinity with lower heat consumption as well as lower water content which can be considered as a better alternative of cement concrete binder to march towards environmental sustainability.

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“…Research on fresh concrete properties for AAS activated is rather limited compared to the understanding of the material in the hardened state, but in general the available test results show that workability and the setting time are strongly affected by alkali content, modulus and the amount of slag (Qureshi & Ghosh 2013, Lee & Lee 2013.…”

Section: Introductionmentioning

confidence: 99%

Alkali activation of a high MgO GGBS – fresh and hardened properties

Humad

Provis

Ćwirzeń

2018

Magazine of Concrete Research

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In this study, concretes and pastes were produced from a high MgO ground granulated blast furnace slag (MgO content 16.1 wt.%) by alkali activation with various amounts and combinations of sodium carbonate and sodium silicate. Sodium carbonate activators tended to reduce slump compared to sodium silicate at the same dose, and, in contrast to the literature for many blast furnace slags with more moderate MgO, to shorten the initial and final setting times in comparison with concretes activated by sodium silicate for dosages less than 10 wt.%. Higher heat curing temperatures and the use of larger dosages of alkali activators resulted in higher early age cube compressive strength values. The XRD analysis of 7 and 28 days old pastes activated with sodium carbonates revealed formation of gaylussite, calcite, nahcolite and C-(A)-S-H gel. Curing at 20˚C appeared to promote dissolution of gaylussite and calcite, while heat curing promoted their replacement with C-(A)-S-H, which also resulted in higher ultimate cube compressive strength values. Conversely, mixes activated with sodium silicate contained less crystalline phases and more disordered gel which strengthened the binder matrix.

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Workability and Setting Time of Alkali Activated Blast Furnace Slag Paste

Cited by 9 publications

References 9 publications

Geopolymer Based on Mechanically Activated Air-cooled Blast Furnace Slag

Geopolymer Based on Mechanically Activated Air-cooled Blast Furnace Slag

Enhancing the Mechanical and Microstructural Properties of Silica Fume Blended Fly Ash Based Geopolymer Using Murram as a Tertiary Supplement

Alkali activation of a high MgO GGBS – fresh and hardened properties

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