Conception of an isothermal calorimeter for concrete— Determination of the apparent activation energy

Broda, Michael; Wirquin, Eric; Duthoit, B.

doi:10.1007/bf02483141

Cited by 17 publications

(5 citation statements)

References 3 publications

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“…The apparent activation energies of nucleation rate constant ( I ), growth rate constant ( G ), and generalized diffusion constant ( k D ) are 36.0 kJ/mol, 37.5 kJ/mol, and 42.0 kJ/mol, respectively. The average value of these apparent activation energies of various kinetic parameters is closely to the values in the previous researches from Broda . and Ravikumar, who found that the apparent activation energy of the overall hydration reaction of cement is approximately 37.0 ~ 38.0 kJ/mol.…”

Section: Analysis Of the Kinetics Parameterssupporting

confidence: 86%

A new hydration kinetics model of composite cementitious materials, part 1: Hydration kinetic model of Portland cement

et al. 2019

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This work is the first part of an overall research project that aims to model the hydration kinetics of modern composite cementitious materials. The aim of this part is to build a hydration kinetic model to characterize the hydration behavior of cement at all ages. In this paper, the nucleation and growth of CSH and the diffusion of water are described by a modified BNG model and a modified Jander's model. The kinetic parameters are obtained by simulative fitting of the model to the experimental data. The linear functions between the nucleation and growth rates and the W/C ratios are given in this paper. The apparent activation energy of the nucleation rate constant, growth rate constant, and generalized diffusion constant are approximately 36.0, 37.5, and 42.0 kJ/mol, respectively. Finally, the phase compositions of hardened cement paste are calculated according to the kinetic model and the reaction formula of cement.

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Section: Analysis Of the Kinetics Parameterssupporting

confidence: 86%

A new hydration kinetics model of composite cementitious materials, part 1: Hydration kinetic model of Portland cement

et al. 2019

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“…Using the calorimetry data, the maximum heat released (Q') was calculated to derive the degree of hydration (DOH), defined as the heat at any given time divided by the maximum heat released (Q / Q'), as one of the necessary steps to calculate the activation energy (Ea) (42,43). In this calculation, the limestone is considered as inert (44,45).…”

Section: Calorimetry and Activation Energy Calculationmentioning

confidence: 99%

Performance of Portland Limestone Cements: Cements Designed to Be More Sustainable That Include up to 15% Limestone Addition

Barrett¹

2013

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ACKNOWLEDGMENTSThis work was conducted in the Charles Pankow Concrete Materials Laboratory at Purdue University. As such, the authors gratefully acknowledge the support which has made this laboratory and its operation possible.The authors would like to thank Buzzi Unicem, Holcim, Lafarge, Lehigh Hanson, and Omya for graciously providing the cementitious materials for this research. JOINT TRANSPORTATION RESEARCH PROGRAMThe Joint Transportation Research Program serves as a vehicle for INDOT collaboration with higher education institutions and industry in Indiana to facilitate innovation that results in continuous improvement in the planning, design, construction, operation, management and economic efficiency of the Indiana transportation infrastructure. https://engineering.purdue.edu/JTRP/index_html Published reports of the Joint Transportation Research Program are available at: http://docs.lib.purdue.edu/jtrp/ NOTICEThe contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views and policies of the Indiana Department of Transportation or the Federal Highway Administration. The report does not constitute a standard, specification or regulation. AbstractIn 2009, ASTM and AASHTO permitted the use of up to 5% interground limestone in ordinary portland cement (OPC) as a part of ASTM C150/AASHTO M85. When this project was initiated a new proposal was being discussed that would enable up to 15% interground limestone to be considered in ASTM C595/AASHTO M234 cement. This project was initiated to provide rapid feedback to INDOT for use in discussions regarding these specifications (this has become ASTM C595/AASHTO M234). PLC is designed to enable more sustainable construction which may significantly reduce the CO2 that is embodied in the built infrastructure while extending the life of cement quarries. The physical and chemical properties of the cementitious materials used in this study were examined. PLC is typically a finer cement (10 to 30% Blaine fineness) with a reduction in the coarse clinker particles (>20µm) and an increase in fine particles which are primarily limestone. Isothermal calorimetry and chemical shrinkage results imply that these PLC materials have a similar or slight greater reaction and would be able to be used interchangeably with OPC in practice as it relates to the rate of reaction. The PLC mortars exhibited relatively similar activation energies compared to the corresponding OPCs allowing the maturity method to be used by INDOT for both the PLC and OPC systems. The mechanical properties of OPC and PLC were generally similar with the PLC typically having slightly higher early age strengths but similar 28 day strengths. No significant change in drying shrinkage or restrained shrinkage cracking was observed for the PLC when compared with OPC (Barrett et al. 2013 In 2009, ASTM and AASHTO permitted the use of up to 5% interground limestone in ordinary portland ceme...

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“…In this study, the rate method [43][44][45] has been applied to determine the discussed energy. Following this method, the apparent activation energy, E a , is calculated based on heat evolution rates q 1 and q 2 , consistent with the same evolved heat, Q i , and two curing temperatures, T 1 and T 2 :…”

Section: Experimental Programmentioning

confidence: 99%

Thermal Properties of Calcium Sulphoaluminate Cement as an Alternative to Ordinary Portland Cement

2021

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This paper presents the results of research into the heat of hydration and activation energy of calcium sulphoaluminate (CSA) cement in terms of the dependence on curing temperature and water/cement ratio. Cement pastes with water/cement ratios in the range of 0.3–0.6 were tested by isothermal calorimetry at 20 °C, 35 °C and 50 °C, with the evolved hydration heat and its rate monitored for 168 h from mixing water with cement. Reference pastes with ordinary Portland cement (OPC) were also tested in the same range. The apparent activation energy of CSA and OPC was determined based on the results of the measurements. CSA pastes exhibited complex thermal behaviour that differed significantly from the thermal behaviour of ordinary Portland cement. The results show that both the w/c ratio and elevated temperature have a meaningful effect on the heat emission and the hydration process of CSA cement pastes. The determined apparent activation energy of CSA revealed its substantial variability and dependence, both on the w/c ratio and the curing temperature.

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Conception of an isothermal calorimeter for concrete— Determination of the apparent activation energy

Cited by 17 publications

References 3 publications

A new hydration kinetics model of composite cementitious materials, part 1: Hydration kinetic model of Portland cement

A new hydration kinetics model of composite cementitious materials, part 1: Hydration kinetic model of Portland cement

Performance of Portland Limestone Cements: Cements Designed to Be More Sustainable That Include up to 15% Limestone Addition

Thermal Properties of Calcium Sulphoaluminate Cement as an Alternative to Ordinary Portland Cement

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