Effects of selected inorganic chemical activators on properties and hydration mechanism of high volume fly ash (HVFA) binders

Rakić, Jelena; Petrović, Rada; Radojević, Vesna; Baščarević, Zvezdana

doi:10.1016/j.conbuildmat.2023.131833

Cited by 7 publications

(3 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They reported the presence of unreacted clinker minerals observed as large irregular areas that appeared light grey in the SEM BSE images, similar to the observations of Supit et al (2014). Rakic et al (2023) [106] also reported that the hydration products of the HVFA binders were a mix of CASH, CSH, and aluminosilicate gels of different compositions. Using XRD analysis, Supit et al (2014) [103] observed that the ultra-fine fly ash can effectively increase the CH consumption level of HVFA pastes and, hence, the production of additional CSH gels due to the higher amorphous SiO 2 content in UFFA [10].…”

Section: Microstructural Analysissupporting

confidence: 62%

“…At 90 days of age, they observed that SEM images of carbon-based HVFA showed hydrated FA, dense CSH gel, and CH crystals compared with that of Pc binders and HVFA binders without carbon, which showed irregular loose CSH gel and unhydrated FA and CH crystals, respectively. Similarly, Rakic et al ( 2023) [106] used SEM to investigate the effects of Na 2 SO 4 , Na 2 CO 3 , and Na 2 SiO 3 as chemical activators in HVFA binders containing 70% FA dosages. Using SEM image analysis, they observed that the HVFA pastes were significantly more porous than Pc binders.…”

Section: Microstructural Analysismentioning

confidence: 99%

See 1 more Smart Citation

Strength and Durability Properties of High-Volume Fly Ash (HVFA) Binders: A Systematic Review

Runganga,

Okonta,

Musonda

2024

CivilEng

View full text Add to dashboard Cite

South Africa is endowed with a wealth of coal-fired power stations that can produce extremely high volumes of fly ash per year exceeding 34 million tonnes. The use of high-volume fly ash (HVFA) binders in the construction sector has the capacity to significantly reduce greenhouse gas emissions associated with traditional cement production and offset the carbon footprint of Eskom. The excessive production of fly ash by Eskom warrants the need for developing ultra-high-volume fly ash binders (UHVFA, fly ash/binder > 60 wt%). Nonetheless, fly ash (FA) replacement of cement is still largely limited to 35% regardless of more ambitious research indicating the potential to surpass 60%. In view of the urgent need for South Africa to offset and reduce its carbon footprint, this work reviews and summarises the literature on the performance of HVFA binders with a focus on two specific areas: (i) strength and (ii) durability. On HVFA binder strength, the focus is drawn on work that analysed the compressive strength, flexural strength, and split tensile strength. This review focuses on the extant literature analysing the durability of HVFA binders using various tests, including sorptivity, resistivity, permeability, tortuosity, rapid chloride penetration tests, resistance to sulphate attack, and microstructural analysis. As the FA content increases towards optima, i.e., 50–80%, the most indicative composite characteristics of the strength and durability properties are UCS (30–90 MPa) and permeability (low). This review reveals the leading methodologies, instrumentation, findings, challenges, and contradictions.

show abstract

Section: Microstructural Analysissupporting

confidence: 62%

Section: Microstructural Analysismentioning

confidence: 99%

Strength and Durability Properties of High-Volume Fly Ash (HVFA) Binders: A Systematic Review

Runganga,

Okonta,

Musonda

2024

CivilEng

View full text Add to dashboard Cite

show abstract

“…Malhorta and Mehta studied the effects of high-volume fly ash (HVFA) concrete, with fly ash making up more than 50% of the total mass of the binder, and obtained even better durability performances than OPC-based concrete [ 41 , 72 , 73 , 74 ]. These attributes are extremely beneficial when used as mass concrete [ 75 , 76 , 77 ].…”

Section: Introductionmentioning

confidence: 99%

Mass GGBFS Concrete Mixed with Recycled Aggregates as Alkali-Active Substances: Workability, Temperature History and Strength

Huo

Huang²,

Han

et al. 2023

Materials

View full text Add to dashboard Cite

This study provides the results of an experiment on the possibility of using high-volume ground granulated blast furnace slag (HVGGBFS)-based concrete as mass concrete. In addition to the control concrete, the total weight of the binder was 75% ground granulated blast furnace slag (GGBFS) and 25% ordinary Portland cement (OPC). For the aggregates, both natural and recycled aggregates were used. Three specimens with dimensions of 800 mm × 800 mm × 800 mm were prepared to simulate mass concrete. The workability, temperature aging and strength of the mass concrete were tested. The test results showed that utilizing HVGGBFS concrete as mass concrete can significantly reduce the heat of hydration due to the low heat of hydration of GGBFS, while the heat of hydration of GGBFS and recycled aggregate combination is 11.2% higher than normal concrete, with a slump that is 31.3% lower than that of plain concrete. The results also showed that the use of recycled aggregates in HVGGBFS concrete can significantly reduce workability. However, the compressive strength is higher than when natural aggregates are used due to the alkali activation effect caused by the recycled aggregates. The compressive strength at 7 and 28 days increased by 33.7% and 16.3%, respectively.

show abstract

Comparative study on the preparation of phosphate-based geopolymers using different activators

Zeng,

Pu,

Cai

et al. 2024

Construction and Building Materials

View full text Add to dashboard Cite

Effects of selected inorganic chemical activators on properties and hydration mechanism of high volume fly ash (HVFA) binders

Cited by 7 publications

References 59 publications

Strength and Durability Properties of High-Volume Fly Ash (HVFA) Binders: A Systematic Review

Strength and Durability Properties of High-Volume Fly Ash (HVFA) Binders: A Systematic Review

Mass GGBFS Concrete Mixed with Recycled Aggregates as Alkali-Active Substances: Workability, Temperature History and Strength

Comparative study on the preparation of phosphate-based geopolymers using different activators

Contact Info

Product

Resources

About