Author(s):
B.M. Gallaway, R.E. Schiller, J.G. Rose
Publication Date
1971
Abstract
Reported herein are the results of a study concerned with determining the amount of water which can be expected to exist on various pavement types under normal ranges of pavement cross slopes, rainfall intensities, pavement textures, and drainage lengths. Equations are developed which relate these variables and their relative effects to water depth. Results are presented in both tabular and graphic form. Background information are pertinent past research pertaining to hydraulics of water flow over paved surfaces are given.|Nine different type surfaces were tested. The surfaces were placed on individual 28-foot long by 4-foot wide, double tee, prestressed concrete beams. Rainfall of uniform intensity was applied to the surface. Water depth measurements were taken at regularly spaced drainage lengths for various combinations of rainfall intensity and pavement cross slope. Multiple regression analyses were used to determine the best fit of the data.|Pavement cross slope was found to affect water depths significantly. For a rainfall intensity of 1.5 in/hr, a surface texture of 0.03 in., and a drainage length of 24 ft., increasing the cross slope from l/16 in/ft (1/192) to 1/4 in/ft (l/48) decreased water depths by 62 percent in the outside wheel path (approximately 21 feet from the top of the drainage area). Correspondingly, increases in surface texture decreased water depths; whereas, increases in rainfall intensity and drainage length increased water depths. The overall experimentally obtained equation is d = [3.38 x 10 (exponent -3) (1/T) exponent -.11 (L) exponent .43 (I) exponent .59 (1/S) exponent .42] - T where d = average water depth above top of texture (in); T = average texture depth (in); L = drainage-path length (ft); I = rainfall intensity (in/hr); and S = cross slope (ft/ft).|The findings and conclusions contained herein will be useful to the highway engineer in determining proper geometric designs and paving materials commensurate with acceptable pavement friction characteristics and service demands. Suggestions for further research are also included.
Report Number:
138-5
Link(s):
Document/Product
http://tti.tamu.edu/documents/138-5.pdf
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