Synthesis and properties of calcium sulphoaluminate using fluidised-bed boiler ash

Na, S.; Song, Myong-Shin; Kang, Sung-Dae; Lee, S.; Kim, K.

doi:10.1179/1432891715z.0000000001799

Cited by 2 publications

(9 citation statements)

References 4 publications

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“…It has been suggested that the frost resistance of concrete is best at an MEA mass fraction of about 3% and that excessive dosage of MEA negatively affects the frost resistance [13]. This corresponds to the results achieved in this study, in which the RDME of the UM 21 was highest among the concretes while its MLR was lowest.…”

Section: Fast-damage Stagesupporting

confidence: 88%

“…UEA and MEA were used to develop the shrinkage compensating concrete. The mechanism of these expansive agents can be explained in terms of their respective hydration reactions, which are given by the following equations [10,21,23]:…”

Section: Methodsmentioning

confidence: 99%

“…It is seen from Figure 3 that the RDME of UM 10 changed most significantly and decreased the fastest, with an average rate of decline of 20.02%. After 75 cycles, the RDMEs of the respective concretes were, in the order from highest to lowest, UM 21 > UM 41 > UM 11 > UM 10 > PC, while the MLRs were, in the order from highest to lowest, PC > UM 10 > UM 11 > UM 41 > UM 21 . These results can be attributed to the fact that, by this age, the UEA hydration reaction in concrete has been essentially completed but there was a lack of other hydration products to continually improve the pore structures of the concretes.…”

Section: Fast-damage Stagementioning

confidence: 99%

“…The mass fraction of UEA in a group of concrete is twice that of MEA, while the mass of UEA in the other group of concrete is four times that of MEA. Therefore, five mix designs-a plain concrete (PC control) and four shrinkage compensating concretes, called UM 10 , UM 41 , UM 21 , and UM 11 -with mixture ratios of 1:0, 4:1, 2:1, and 1:1, respectively, were developed.…”

Section: Concrete Mixesmentioning

confidence: 99%

“…Sung et al used a CSA-based expansive additive to compensate for the shrinkage of alkali-activated material (AAM) mortar, resulting in an expansive agent with an excellent compensation effect on drying shrinkage at early ages, although the long-term effect was minimal [20]. In Na et al's study, it was found that early-age frost resistance can be improved through the use of CSA-based expansive agents, which reduce or even prevent the formation of microcracks, although the effect was not obvious in later periods [21]. However, most such studies have focused on the improvement of frost resistance at a specific application age instead of focusing on all ages.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Study on Freezing and Thawing Cycles of Shrinkage-Compensating Concrete with Double Expansive Agents

Guo

Zhang

et al. 2020

Materials

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The freezing and thawing of construction concrete is becoming an increasingly important structural challenge. In this study, a shrinkage-compensating concrete based on a double expansive admixture was developed and its frost resistance was assessed through rapid freezing and thawing cycling. The frost resistance of the concrete was derived through the measurement and calculation of the relative dynamic modulus of elasticity (RDME) and the mass loss rate (MLR), and the freezingand thawing-cycle microstructures and products of concretes with different expansive agents were analyzed using scanning electron microscopy (SEM). It was shown that changes in the properties of the concrete under freezing and thawing could be divided into three stages: slow-damage stage, fast-damage stage, and stable stage. Compared to concrete without an expansive agent, a single-expansive-agent concrete demonstrated excellent frost resistance during the slow-damage stage, but the frost resistance rapidly decreased during the fast-damage age. After 150 cycles (the stable-damage stage), the concrete with a U-type expansive agent (UEA): MgO expansive agent (MEA) mix proportion of 2:1 had the best frost resistance, with RDME and MLR values 17.35% higher and 25.1% lower respectively, than that of an expansive-agent-free concrete. These test results provide a basis for the study of frost resistance in large-scale hydraulic concrete structures.

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Section: Fast-damage Stagesupporting

confidence: 88%

Section: Methodsmentioning

confidence: 99%

Section: Fast-damage Stagementioning

confidence: 99%

Section: Concrete Mixesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental Study on Freezing and Thawing Cycles of Shrinkage-Compensating Concrete with Double Expansive Agents

Guo

Zhang

et al. 2020

Materials

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Hardening Properties of Foamed Concrete with Circulating Fluidized Bed Boiler Ash, Blast Furnace Slag, and Desulfurization Gypsum as the Binder

Na¹,

Lee²,

Song³

2021

OJCE

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Recently, a large amount of circulating fluidized bed boiler ash (CFBA) and desulfurization gypsum (DSG) has been produced, and it is essential to develop technology to utilize them. These materials have CaO and SO 3 , which are considered to be a stimulant for blast furnace slag (BFS). This study presents an experimental investigation of the compressive strength and heavy metal ions immobilization properties of cement-free materials comprising CFBA, BFS, and DSG. The feasibility of manufacturing foamed concrete using these materials was examined, and field test of foamed concrete was conducted. Experimentally, the flow, compressive strength, and heavy metal ions concentration were evaluated via inductively coupled plasma atomic emission spectroscopy (ICP-AES) of the paste and foamed concrete. The experimental investigation revealed the self-healing hardening ability of fluidized bed boiler ash. In addition, the compressive strength was increased with the increasing replacement rates of BFS and DSG in the CFBA paste, and the compressive strength of 14.6 -17.2 MPa was recorded over 28 days of curing. From the result obtained, the feasibility of manufacturing foamed concrete with a foam volume of 120 L, incorporating the aforementioned materials, is confirmed. It was also found that after 28 days of age, a 7.9-MPa compressive strength of the foamed concrete was attained, and heavy metal ions elution in this foamed concrete was also significantly reduced. Therefore, CFBA, BFS, and DSG could be used as a binder for the foamed concrete.

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Synthesis and properties of calcium sulphoaluminate using fluidised-bed boiler ash

Cited by 2 publications

References 4 publications

Experimental Study on Freezing and Thawing Cycles of Shrinkage-Compensating Concrete with Double Expansive Agents

Experimental Study on Freezing and Thawing Cycles of Shrinkage-Compensating Concrete with Double Expansive Agents

Hardening Properties of Foamed Concrete with Circulating Fluidized Bed Boiler Ash, Blast Furnace Slag, and Desulfurization Gypsum as the Binder

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