Recent progress in understanding setting and hardening of alkali-activated slag (AAS) materials

Jiang, Dongdong; Shi, Caijun; Zhang, Zuhua

doi:10.1016/j.cemconcomp.2022.104795

Cited by 54 publications

(14 citation statements)

References 147 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The setting times are generally found to decrease with an increase in slag content in the binder system. This is attributable to the enhanced availability of Ca 2+ ions (liberated from the surface of the slag particles) that combine with [SiO 4 ] 4− ions liberated from Na-Si or K-Si, enhancing the amount of early reaction product formation [44,45]. The Na 2 O content (proportional to the n value) has a significant effect on the setting times, as has been elucidated in our previous work on pure fly ash or slag-based activated binders [38].…”

Section: Setting Timesmentioning

confidence: 99%

A Comparison of the Effect of Activator Cations (Sodium and Potassium) on the Fresh and Hardened Properties of Mine Tailing-Slag Binders

Surehali,

Simon,

Ramasamy

et al. 2023

Construction Materials

View full text Add to dashboard Cite

This study develops alkali-activated mine tailing (MT)-based binders containing MT as the major source material and slag (S) as a minor additive, using alkaline activators containing sodium or potassium as the cationic species. The influence of the cationic species (Na or K), slag content, alkalinity (expressed using the activator silica modulus, Ms), and alkali oxide-to-powder ratio, n, on the setting behavior, paste rheology, early-age reaction kinetics, and compressive strength development are discussed. The effects of using solid activators are also considered. Changes in Ms values have a stronger impact on setting times compared to n values, underscoring the significant role of silicate species from the activator in the initial reaction mechanisms. The type of cation and physical state of the activator (in the case of K–Si-activated systems) are found to determine the dissolution rate and mobility of ionic species in the system, resulting in significant differences in the early age reaction mechanisms (e.g., K-based activators show >2× enhancement in early heat release as compared to Na-based activators) of the alkali-activated binders prepared using the same activator parameters. The difference in the viscosities of the activator solutions strongly influences the rheological characteristics of the activated systems. MT-based binders with 28-day compressive strengths ranging from 10 to 35 MPa, which are suitable for several structural/non-structural applications, are attained. The strong dependence of the compressive strength development on the alkali activation parameters and slag content in the system presents an opportunity to develop sustainable binders, with MT as their major constituent, to provide twin benefits of recycling MT wastes and mitigating the environmental impacts associated with traditional ordinary Portland cement-based binder systems.

show abstract

Section: Setting Timesmentioning

confidence: 99%

A Comparison of the Effect of Activator Cations (Sodium and Potassium) on the Fresh and Hardened Properties of Mine Tailing-Slag Binders

Surehali,

Simon,

Ramasamy

et al. 2023

Construction Materials

View full text Add to dashboard Cite

show abstract

“…During the geopolymerization reactions, precursors of the active form were dissolved in the alkaline solution, and new aluminosilicate phases were formed. Zeolitic crystalline compounds, C-S-H and C-A-S-H, and amorphous alumino-silicate structures are detected in the slag hydration products [21,22]. These new hydration zeolitic compounds are durable at elevated temperatures [23].…”

Section: Introductionmentioning

confidence: 96%

Alkali-Activated Slag Coatings for Fire Protection of OPC Concrete

Kielė,

Vaičiukynienė,

Bertašius

et al. 2023

Materials

View full text Add to dashboard Cite

During a fire, ordinary Portland cement (OPC) systems lose their mechanical properties. For this reason, it is important to find a way to protect it. This study suggested alternative uses of slag and phosphogypsum to produce coatings for fire-resistant applications. Five compositions of 10 mm thick alkali-activated slag coatings were investigated. In these compositions, different amounts of phosphogypsum (1%, 3%, 5%, 7%, and 10%) were used. In the first stage of this study, the residual compressive strength of samples with the coatings based on alkali-activated slag was compared to the results of OPC concrete samples without coatings. The experimental results showed that a higher residual compressive strength of 33.2–47.3 MPa OPC concrete was achieved for the samples with coatings. Meanwhile, the residual compressive strength of the uncoated samples was 32.37 MPa. In the second stage, OPC concrete samples were reinforced with fiberglass polymer (FRP) rods, and they had a similar positive effect on alkali-activated coatings. After exposure to higher temperatures, the pullout tests of the glass FRP bars showed that the adhesion strength was (9.44 MPa) 43.9% higher for the samples with coatings compared to the samples without coatings (6.56 MPa). Therefore, a higher bond strength can be maintained between concrete and FRP bars. Alkali-activated slag with 3% phosphogypsum can be used for the production of fire-resistant coating. These coatings could protect OPC concrete and reinforced concrete with glass FRP bars from fire.

show abstract

“…Although the mechanical properties and durability of alkali-activated slag (AAS) binder are excellent, the AAS binder has poor workability [13][14][15][16]. The fluidity is greatly lost in a very short period of time, and the fast setting and hardening are observed [17][18][19]. At present, many researchers use FA to improve the workability of AAS.…”

Section: Introductionmentioning

confidence: 99%

Effect of Steel Slag on Hydration Kinetics and Rheological Properties of Alkali-Activated Slag Materials: A Comparative Study with Fly Ash

Han,

Zhu,

Zhang

et al. 2024

Materials

View full text Add to dashboard Cite

The effects of steel slag (SS) and fly ash (FA) on hydration heat, fluidity, setting time and rheological properties of alkali-activated slag (AAS) pastes with different silicate modulus (Ms) values were comparatively investigated. The results show that the incorporation of SS shortens the induction period, increases the cumulative hydration heat, improves the initial fluidity and decreases the setting time at low Ms, but the opposite trend is found at high Ms. FA significantly retards the reaction, reduces the hydration heat, increases the fluidity and prolongs the setting time. The addition of SS or FA reduces the yield stress and plastic viscosity of AAS paste. SS improves the rheological properties of AAS paste more significantly than that of FA at high Ms. The yield stress and plastic viscosity of AAS paste with SS or FA rise with the increasing Ms and decline with the increasing water/binder (w/b) ratio.

show abstract

Recent progress in understanding setting and hardening of alkali-activated slag (AAS) materials

Cited by 54 publications

References 147 publications

A Comparison of the Effect of Activator Cations (Sodium and Potassium) on the Fresh and Hardened Properties of Mine Tailing-Slag Binders

A Comparison of the Effect of Activator Cations (Sodium and Potassium) on the Fresh and Hardened Properties of Mine Tailing-Slag Binders

Alkali-Activated Slag Coatings for Fire Protection of OPC Concrete

Effect of Steel Slag on Hydration Kinetics and Rheological Properties of Alkali-Activated Slag Materials: A Comparative Study with Fly Ash

Contact Info

Product

Resources

About