Examination of Drying and Psychrometric Properties of High Water-Cement Ratio Concretes

dc.contributor.authorMcNicol, Thomas Jamesen
dc.contributor.committeechairLeon, Roberto T.en
dc.contributor.committeechairHindman, Daniel P.en
dc.contributor.committeememberRoberts-Wollmann, Carin L.en
dc.contributor.departmentCivil and Environmental Engineeringen
dc.date.accessioned2016-03-23T08:00:46Zen
dc.date.available2016-03-23T08:00:46Zen
dc.date.issued2016-03-22en
dc.description.abstractMoisture from concrete has been estimated to be responsible for over $1 billion annually from damages in floor coverings. To prevent damages, flooring manufacturers require installers to test concrete moisture levels to determine if the concrete has dried sufficiently to receive flooring or covering. Two of the main tests used in the United States to determine concrete moisture levels are moisture vapor emissions rate (MVER) tests and relative humidity (RH) tests. Changes in ambient temperature can affect the results of both RH and MVER tests. The goal of this study was to investigate the effects of ambient temperature changes on the RH of concrete, and compare the sensitivity of RH measurements to the results of MVER tests at the same ambient temperature. The RH of concrete was measured at 20%, 40%, 60%, and 80% of depth in each sample and tracked over a period of 24 days to develop drying curves at each depth, and drying profiles of each sample. The changes in concrete RH due to a change in ambient temperature were predicted using the psychrometric process and a model developed during this study. Due to size constraints on the concrete samples, ASTM 1869 had to be altered during the MVER tests. Typical RH change in the concrete samples was under 4% RH after either an increase or decrease in an ambient temperature of 5.5°C (10°F). The psychrometric process predicted that the concrete RH would change between 20% - 40% RH after the ambient temperature changed by 5.5°C. Psychrometric properties were not able to full describe the behavior of air in concrete pores so a new model was created to better predict the change in concrete RH after a change in ambient temperature. The developed model was able to predict concrete RH change within 5% error over the range of tested temperatures.en
dc.description.degreeMaster of Scienceen
dc.format.mediumETDen
dc.identifier.othervt_gsexam:7320en
dc.identifier.urihttp://hdl.handle.net/10919/64973en
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectConcrete Moisture Testingen
dc.subjectConcrete Relative Humidity Testingen
dc.subjectPsychrometric Propertiesen
dc.subjectConcrete Slabs for Flooringen
dc.titleExamination of Drying and Psychrometric Properties of High Water-Cement Ratio Concretesen
dc.typeThesisen
thesis.degree.disciplineCivil Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen
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