Committee Chair

Thomas, Tricia A.

Committee Member

Jones, Frank; Onyango, Mbakisya A.; Sutton, William; Walker, Randy;

Department

Dept. of Engineering

College

College of Engineering and Computer Science

Publisher

University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)

Abstract

In an effort to determine how and what debris clogs well-aged pervious concrete, a fourteen-year-old pervious concrete parking lot was cored and the samples investigated. First, a falling head test was performed to determine the infiltration rates on the samples, and the distribution was such that the infiltration rates were inversely proportional with the areas of greatest flow during a rainfall. The samples were then swept and the falling head test was performed again; and then the samples were pressure washed and the tests were performed one final time. Sweeping removed little debris from the surface, but did significantly increase the infiltration. Pressure washing removed a relatively significant amount of debris from the samples, and also significantly increased the infiltration rates. The samples were then broken to determine if any remaining debris was in the samples. Pressure washing did not completely remove the debris from the samples. A separate set of samples was broken and the aggregate was separated from the debris. The debris removed was compared to the surrounding soil via a sieve analysis, cohesion tests, and organics analysis. When the samples were broken open, several of the samples happened to split in half to reveal a cross-section of the clogging layer. When measured, it was revealed that the depth of clogging on these pervious concrete samples was one inch or more in some areas, which contradicts previous research of laboratory clogged samples, that says the maximum depth of clogging on a pervious concrete can only get to one-quarter of an inch. The sieve analysis revealed that the debris was of a similar gradation to the surrounding soils; however, there were some larger particles than the surrounding soils, which looked like the aggregate from the nearby asphalt road. A cohesion test revealed that while there was clay in the surrounding soils, there was not enough cohesion in the debris removed from the pervious concrete samples to suggest that much clay was retained inside the pervious concrete. An organics analysis suggested that little organic matter, typically less than five percent, was in the pervious concrete, which is less organic matter than was in the surrounding soils. One of the largest setbacks to pervious concrete’s more widespread use in the construction industry is that it clogs. By understanding what debris clogs a pervious concrete sample, it gives a better understanding of the clogging process. This can help in two main ways: by modifying the design of pervious concrete so that it does not clog as easily, expanding its lifetime or by determining a better method for removing debris from a pervious concrete sample through routine maintenance.

Degree

M. S.; A thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Master of Science.

Date

5-2014

Subject

Lightweight concrete -- Testing; Pavements; Concrete -- Design and construction

Keyword

clogging elements in pervious concrete

Document Type

Masters theses

Extent

xi, 149 leaves

Language

English

Rights

Under copyright.

License

http://creativecommons.org/licenses/by/3.0/

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