Effects of Mixing Variables on Early-Age Characteristics of Portland Cement Systems
Publication: Journal of Materials in Civil Engineering
Volume 28, Issue 10
Abstract
The performance and economy of infrastructure system is dependent on the specifications used to construct it. Good specifications contain requirements that correlate with improved performance and/or economy. There are several standards and specifications for mixing field concrete. These documents provide requirements for the mixing process. However, limited research has been performed on how mixing time and number of drum revolutions affect concrete characteristics. With advanced technologies that can delay the set and improve the workability, the current documents may not be applicable. This paper presents an assessment of pastes and mortars mixed for different times and varying number of mixer revolutions. Early-age characteristics include the assessment of time-variant ion concentration in solution, flowability, setting time, and chemical shrinkage. Results indicate that these early-age characteristics of pastes and mortars mixed in the laboratory are influenced by the mixing time and number of mixer revolutions. The rate of dissolution () of ions in solution and temperature are the material parameters directly affected by the mixing processes and these parameters can alter the rates of hydration reactions, resulting in changes of the early-age characteristics of cement systems.
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Acknowledgments
This study was supported by the Washington Department of Transportation (WSDOT) as part of the project, Extended Discharge Time and Revolution Count for Cast-In-Place Concrete.
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Published In
Journal of Materials in Civil Engineering
Volume 28 • Issue 10 • October 2016
Copyright
© 2016 American Society of Civil Engineers.
History
Received: Mar 3, 2015
Accepted: Feb 4, 2016
Published online: Apr 22, 2016
Discussion open until: Sep 22, 2016
Published in print: Oct 1, 2016
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