Effects of deicing salt on physical properties of aggregate base material /
The winter application of deicing salts to pavements in cold regions can lead to high salt concentrations in pavement base layers. This project investigates the effects of salts on the electrical, mechanical, and hydraulic properties of aggregate base material. These properties are important in pa...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2002.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=765069691&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The winter application of deicing salts to pavements in cold regions can lead to high salt concentrations in pavement base layers. This project investigates the effects of salts on the electrical, mechanical, and hydraulic properties of aggregate base material. These properties are important in pavement design, maintenance, and rehabilitation activities since accurate evaluations of pavement condition and the causes of damage are essential for determining optimum pavement preservation strategies. Laboratory experiments were conducted using calcium, magnesium, and sodium chlorides at two concentrations each for comparison against untreated aggregate specimens during freeze-thaw and dry-wet cycles. Dielectric and electrical conductivity values were measured together with Young's modulus and specimen densities at each temperature or time of interest. Statistical techniques indicate that salt effects are most pronounced during freezing and during the intermediate and later stages of drying. Numerical models developed in the study were subsequently utilized to investigate the effects of both salt type and concentration on freezing and evaporation from a theoretical perspective. This study concludes that salts have significant effects on the electrical, mechanical, and hydraulic properties of aggregate base material and that salt concentration rather than the type of salt has more influence on the measured responses. Higher concentrations yielded significantly higher dielectric and electrical conductivity values than lower concentrations during freezing and during drying due to the greater freezing point depressions and enhanced water retention characteristics, respectively, of the former. Higher salinity corresponded to comparatively reduced ice contents and lower modulus values at freezing temperatures. After further study and validation, the freezing and evaporation models developed in this project should be integrated in a computer program for predicting frost heave in pavements based on the type and concentration of salts dissolved in the pore water. |
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| Item Description: | Vita. "Major Subject: Civil Engineering". |
| Physical Description: | xii, 127 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 109-116). |