Chemical activation of binary slag cement with low carbon footprint

Zhao, Yingliang; Qiu, Jingping; Jin, Xing; Sun, Xiaogang

doi:10.1016/j.jclepro.2020.121455

Cited by 85 publications

(17 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…With extra sulfate ions, quicklime can be hydrated to form dihydrate gypsum, which also leads to the hardening of CPB [ 42 ]. However, when sulfate ions are consumed, monosulfoaluminate is formed instead of ettringite [ 43 , 44 ].As a result of low crystallinity, the filler effect of AFm on CPB is low [ 25 ]. Furthermore, FA activated by quicklime hydration participates in the hydration reaction and decreases pH with increasing curing time.…”

Section: Resultsmentioning

confidence: 99%

“…As discussed in the literature [ 25 , 26 , 38 , 39 ], the hydration process of pure binder pastes cured for 3, 7, and 28 days, respectively, was stopped by isopropyl alcohol. Samples were pulverized after drying in a vacuum drying oven to a constant weight at 45 °C.…”

Section: Methodsmentioning

confidence: 99%

“…(2) Phase composition analysis of binder pastes was performed using thermogravimetry analysis STA409PC (Selb, Germany) coupled with differential thermogravimetry (DTG). About a 30 mg sample was loaded into an alumina crucible and heated to 1000 °C in a nitrogen atmosphere (15 °C/min) [ 25 , 26 ]. The amount of hydrate water (H) and portlandite (CH) can be expressed as:

where M 50 , M 400 , and M 550 correspond to the residual mass of samples at temperatures of 50 °C, 400 °C, and 550 °C, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…The addition of FA reduces the rheological properties and improves the flowability of the fresh backfill due to the lubrication effect of spherical morphology [ 22 ]. Besides, FA, rich in aluminum and silicon, can be involved in cement hydration and form hydrate products (e.g., calcium silicate hydrate, calcium aluminate hydrate, and ettringite) that affect strength development [ 23 , 24 , 25 , 26 ]. Deschner et al [ 27 ] documented that with an early hydration time of up to 2 days, cement hydration is mainly affected by the so-called “filler effect” of FA.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Quicklime and Calcium Sulfoaluminate Cement Used as Mineral Accelerators to Improve the Properties of Cemented Paste Backfill with a High Volume of Fly Ash

Ding

Zhang

2020

Materials

View full text Add to dashboard Cite

In order to reduce the CO2 emission and cost of binders used in cemented paste backfill (CPB) technology, new blended binders with a large amount of fly ash (FA) were fabricated. Different doses of quicklime and calcium sulfoaluminate cement (CṠA) were used as mineral accelerators to improve the early workability of CPB. The effects of CṠA and quicklime on flowability, compressive strength, pore structure, hydration heat, and hydration evolution were investigated experimentally. The results showed that the addition of quicklime and CṠA reduced the spread diameter of the fresh backfill and improved the mechanical performance of the hardened CPB. With increasing quicklime and CṠA, the cumulative hydration heat of the blended binder distinctly increased in the first 6 h. CṠA improved the initial hydration by increasing the reactivity, and quicklime increased the hydration rate by activating FA. The blended binder (15% quicklime + 10% CṠA) with the lowest CO2 emission and cost had potential application in filling technology.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

where M 50 , M 400 , and M 550 correspond to the residual mass of samples at temperatures of 50 °C, 400 °C, and 550 °C, respectively.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Quicklime and Calcium Sulfoaluminate Cement Used as Mineral Accelerators to Improve the Properties of Cemented Paste Backfill with a High Volume of Fly Ash

Ding

Zhang

2020

Materials

View full text Add to dashboard Cite

show abstract

“…Many studies have shown that the pore distribution of pastes can be divided into four size ranges [22,23]: gel micropores (<4.5 nm), mesopores (4.5-50 nm), middle capillary pores (50-100 nm), and large capillary pores (>100 nm). A pore size larger than 50 nm can also be called harmful pores [24]. It can be seen from Figure 7b that when the alkali slag content is ≤ 10%, the volume of gel micropores and mesopores in the paste increased significantly, while the volume of middle capillary pores and large capillary pores decreased.…”

Section: Pore Structurementioning

confidence: 99%

Characterization and Hydration Mechanism of Ammonia Soda Residue and Portland Cement Composite Cementitious Material

Wen

et al. 2021

Materials

View full text Add to dashboard Cite

The use of ammonia soda residue (ASR) to prepare building materials is an effective way to dispose of ASR on a large scale, but this process suffers from a lack of data and theoretical basis. In this paper, a composite cementitious material was prepared using ASR and cement, and the hydration mechanism of cementitious materials with 5%, 10%, and 20% ASR was studied. The XRD and SEM results showed that the main hydration products of ASR-cement composite cementitious materials were an amorphous C-S-H gel, hexagonal plate-like Ca(OH)2 (CH), and regular hexagonal plate-like Friedel’s salt (FS). The addition of ASR increased the heat of hydration of the cementitious material, which increased upon increasing the ASR content. The addition of ASR also reduced the cumulative pore volume of the hardened paste, which displayed the optimal pore structure when the ASR content was 5%. In addition, ASR shortened the setting time compared with the cement group, and the final setting times of the pastes with 5%, 10%, and 20% ASR were 30 min, 45 min, and 70 min shorter, respectively. When the ASR content did not exceed 10%, the 3-day compressive strength of the mortar was significantly improved, but the 28-day compressive strength was worse. Finally, the hydration mechanism and potential applications of the cementitious material are discussed. The results of this paper promote the use of ASR in building materials to reduce CO2 emissions in the cement industry.

show abstract

Creep of Slag Blended Cement Concrete with and Without Activator

Thanh

Tapas

Chandler³

et al. 2023

Lecture Notes in Civil Engineering

View full text Add to dashboard Cite

Partly replacing Portland cement (PC) with lower carbon footprint cementitious materials such as ground granulated blast furnace slag (slag) is considered as a practical method for reducing CO2 emissions in the cement concrete industry. To mitigate the slow reactivity of slag in a cementitious system and enhance early-age strength, the addition of a chemical activator is a solution. However, the effect of the activator on creep behaviour of slag-blended cement concretes remains unclear. This work presents the effect of sodium sulfate (Na2SO4) activator on the compressive creep of PC concrete blended with 50 and 70 wt% slag. Four concrete mixes (with and without 2.5% Na2SO4 activator) containing 395 kg of cementitious material were prepared. The creep strain measurements were conducted on 150 × 300 mm cylindrical specimens for 140 days under sustained compressive load. The results showed that the 70% slag concrete had lower creep strain than 50% slag-blended cement concrete. The presence of Na2SO4 helped reduce the creep strain of 50% slag concrete but slightly increased that of 70% slag-blended cement concrete. In addition, the applicability of the predictive model in AS3600:2018 for the creep behaviour of high slag content concrete was assessed.

show abstract

Chemical activation of binary slag cement with low carbon footprint

Cited by 85 publications

References 49 publications

Quicklime and Calcium Sulfoaluminate Cement Used as Mineral Accelerators to Improve the Properties of Cemented Paste Backfill with a High Volume of Fly Ash

Quicklime and Calcium Sulfoaluminate Cement Used as Mineral Accelerators to Improve the Properties of Cemented Paste Backfill with a High Volume of Fly Ash

Characterization and Hydration Mechanism of Ammonia Soda Residue and Portland Cement Composite Cementitious Material

Creep of Slag Blended Cement Concrete with and Without Activator

Contact Info

Product

Resources

About