Effect of high volume fly ash and metakaolin with and without hydrated lime on the properties of self-compacting concrete

Anjos, Marcos Alyssandro Soares dos; Camões, Aires; Campos, P.; Azeredo, Givanildo; Ferreira, Ruan L.S.

doi:10.1016/j.jobe.2019.100985

Cited by 41 publications

(32 citation statements)

References 31 publications

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“…The third peak (# 3) observed at 700-800 • C represents the decarbonation of the limestone addition present in the cement used and the loss of the remaining water from the decomposition of the hydrated calcium silicate. For the HPC containing fly ash and MK, the peak (# 4) between 160 °C and 180 °C is attributed to the dehydration of the C-A-H and the hydrated calcium silicoaluminates (C-A-S-H) [19]. The peak (# 5) represents the oxidation of Fe2O3 oxide and the decomposition of unburnt coal residues [22].…”

Section: Thermal Conductivitymentioning

confidence: 99%

“…Both of which will bridge the pore system and lead to a reduction of the thermal stresses generated around the pores [22]. In addition, the fineness For the HPC containing fly ash and MK, the peak (# 4) between 160 • C and 180 • C is attributed to the dehydration of the C-A-H and the hydrated calcium silicoaluminates (C-A-S-H) [19]. The peak (# 5) represents the oxidation of Fe 2 O 3 oxide and the decomposition of unburnt coal residues [22].…”

Section: Microstructure Observationsmentioning

confidence: 99%

“…Fly ash (FA), as the most typical SCM, has been extensively studied for the physical and chemical modification of cement hydration, as well as its hardened properties [10,[19][20][21], and numerous reports have confirmed that the introduction of FA can increase the high-temperature resistance of concrete. However, the studies of the effects of FA and its combination with other SCMs, on the properties of HPC subjected to high temperature is still very limited.…”

Section: Introductionmentioning

confidence: 99%

“…However, the studies of the effects of FA and its combination with other SCMs, on the properties of HPC subjected to high temperature is still very limited. Metakaolin (Al 2 O 3 •2SiO 2 •2H 2 O), as a kind of high activity SCMs, can form anhydrous aluminum silicate (Al 2 O 3 •2SiO 2 ) by dehydration at a temperature range of 600 to 900 • C [7,19,22]. This compound makes it possible to improve the high-temperature resistance of HPC containing SCMs subjected to high temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Combined Usage of Supplementary Cementitious Materials on the Thermal Properties and Microstructure of High-Performance Concrete at High Temperatures

Tang

Zhang

et al. 2020

Materials

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Concrete has low porosity and compact microstructure, and thus can be vulnerable to high temperature, and the increasing application of various types of supplementary cementitious materials (SCMs) in concrete makes its high-temperature resistant behavior more complex. In this study, we investigate the effects of four formulations with typical SCMs combinations of fly ash (FA), ultra-fine fly ash (UFFA) and metakaolin (MK), and study the effects of SCMs combinations on the thermal performance, microstructure, and the crystalline and amorphous phases evolution of concrete subjected to high temperatures. The experimental results showed that at 400 °C, with the addition of 20% FA (wt %), the thermal conductivity of the sample slightly increased to 1.5 W/(m·K). Replacing FA with UFFA can further increase the thermal conductivity to 1.7 W/(m·K). Thermal conductivity of concrete slightly increased at 400 °C and significantly reduced at 800 °C. Further, combined usage of SCMs delayed and reduced micro-cracks of concrete subjected to high temperatures. This study demonstrates the potential of combining the usage of SCMs to promote the high-temperature performance of concrete and explains the micro-mechanism of concrete containing SCMs at high temperatures.

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Section: Thermal Conductivitymentioning

confidence: 99%

Section: Microstructure Observationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of Combined Usage of Supplementary Cementitious Materials on the Thermal Properties and Microstructure of High-Performance Concrete at High Temperatures

Tang

Zhang

et al. 2020

Materials

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“…Wanget al [14] carried out an experiment to investigate the effect of FA on mechanical properties and thermal conductivity of HSC, and found that compressive strength reduced about 26% at 550 • C, and the thermal conductivity increased 22% when the relative humidity was 100%. Valencia et al [12] indicated that the residual strength of the FA/GBFS and FA/OPC are 15 and 5.5 MPa, respectively at 1100 • C. Aydinet al [13] showed that the superior properties of FA specimen may be attributed to the strong aggregate-cement paste interfacial transition zone (ITZ) at 900 • C. Furthermore, a series of studies were conducted to investigate the effect of fuel ash [4], high volume fly ash [3,15] and volcanic ash [16] on the performance of HSC exposure to high temperatures. Furthermore, metakaolin (MK) as a kind of high activity SCMs, which can form anhydrous aluminum silicate (Al 2 O 3 •2SiO 2 ) by dehydration at temperatures between 600 • C and 900 • C, making it possible to improving properties of HSC [15,[17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Physical and Mechanical Properties of High-Strength Concrete Modified with Supplementary Cementitious Materials after Exposure to Elevated Temperature up to 1000 °C

Zhou

Yang

et al. 2020

Materials

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This paper presents the experimental findings of a study on the influence of combining usage of supplementary cementitious materials (SCMs) on the performance of high-strength concrete (HSC) subjected to elevated temperatures. In this study, four types of HSC formulations were prepared: HSC made from cement and fly ash (FA), HSC made from cement and ultra-fine fly ash (UFFA), HSC made from cement and UFFA-metakaolin (MK), and HSC made from cement and FA-UFFA-MK. Mechanical and physical properties of HSC subjected to high temperatures (400, 600, 800, and 1000 °C) were studied. Furthermore, the relation between residual compressive strength and physical properties (loss mass, water absorption, and porosity) of HSC was developed. Results showed that the combined usage of SCMs had limited influence on the early-age strength of HSC, while the 28-d strength had been significantly affected. At 1000 °C, the residual compressive strength retained 18.7 MPa and 23.9 MPa for concretes containing 30% UFFA-5% MK and 10% FA-20% UFFA-5% MK, respectively. The specimen containing FA-UFFA-MK showed the best physical properties when the temperature raised above 600 °C. Combined usage of SCMs (10% FA-20% UFFA-5% MK) showed the lowest mass loss (9.2%), water absorption (10.9%) and porosity (28.6%) at 1000 °C. There was a strongly correlated relation between residual strength and physical properties of HSC exposed to elevated temperatures.

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Compressive strength of efficient self‐compacting concrete with rice husk ash, fly ash, and calcium carbide waste additives using multiple artificial intelligence methods

Mohamed

Bashir

Dirar

et al. 2021

Structural Concrete

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The principal benefit of mixed concrete is to minimize the disadvantages of certain complementary cement ingredients by combining them with other better materials so that overall costs are managed and efficiencies of concrete production are increased. The structural and economic characteristics of concrete can also be improved. In this work, the compressive strength (CS) of selfcompacting concrete (SCC) was assessed and their interrelations were addressed using binary and ternary cementitious combinations of rice husk, fly ash (FA), and calcium carbide. Accordingly, various admixtures were prepared with diverse amounts of wastes by substituting ordinary Portland cement (5%). Thus, due to the raising of rice husk and FA, the CS of SCC was considerably improved. To raise the accuracy of the analysis, three soft computing models of particle swarm optimization (PSO), adaptive neuro-fuzzy inference system (ANFIS), and artificial neural network (ANN) were used. Six input parameters comprising FA replacement ratio, rice husk, total cementitious material, water cement ratio, high ratio water reducing agent and age of samples (AS), and one output parameter as the CS of SCC have been investigated. Subsequently, following the root mean square error and R 2 results, three methods were shown as reliable tools for assessing the influence of cementitious material on CS of self-compact concrete; however, ANFIS remarkably was better than ANN and PSO. As a result, rice husk showed less contribution to the strength of concrete at short times, but much at longer time than FA and calcium carbide. The enhanced influence of low amount of calcium carbide on CS was not significant. Also, it was found that the specimen incorporating of cement with 15% calcium carbide showed better workability than that of normal SCC specimen without calcium. Therefore, rice husk ash showed higher potential to be applied as partial replacements in SCC production.Discussion on this paper must be submitted within two months of the print publication. The discussion will then be published in print, along with the authors' closure, if any, approximately nine months after the print publication.

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Effect of high volume fly ash and metakaolin with and without hydrated lime on the properties of self-compacting concrete

Cited by 41 publications

References 31 publications

Effects of Combined Usage of Supplementary Cementitious Materials on the Thermal Properties and Microstructure of High-Performance Concrete at High Temperatures

Effects of Combined Usage of Supplementary Cementitious Materials on the Thermal Properties and Microstructure of High-Performance Concrete at High Temperatures

Physical and Mechanical Properties of High-Strength Concrete Modified with Supplementary Cementitious Materials after Exposure to Elevated Temperature up to 1000 °C

Compressive strength of efficient self‐compacting concrete with rice husk ash, fly ash, and calcium carbide waste additives using multiple artificial intelligence methods

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