Date of Award

8-2011

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Civil Engineering

Advisor

Putman, Bradley J

Committee Member

Rangaraju , Prasad R.

Committee Member

Ravichandran , Nadarajah

Abstract

The goal of this research was to design, implement, and evaluate several retrofit solutions for sealed pervious concrete. Properly functioning pervious concrete pavements allow water to drain through the structure, eliminating the need for traditional drainage infrastructure. A recent study of South Carolina porous pavements (Putman 2010) revealed that some pervious concrete pavements are not properly draining, either because of sealing at the surface. Sealed pavements are generally a result of construction processes, and sealed pavements cannot be fixed with sediment removal techniques such as vacuuming and pressure washing. This study investigates a technique to increase infiltration of sealed pervious concrete by cutting through the sealed layers and allowing water to drain into the void structure of the entire pavement.
Overall, a total of five retrofit techniques, with 29 unique iterations were evaluated. Iterations included partial depth core cuts ranging from breakthrough depth, the depth of the sealed layer of concrete, to two inches below the breakthrough point. Retrofit techniques also included the complete removal of a core, replacing it with washed No. 89 stone and filter fabric to prevent clogging. Linear cut techniques consisted of partial depth cuts, which penetrated the breakthrough layer in various depths and quantities. Infiltration of retrofits was tested using ASTM C 1710 and a box infiltration testing method developed specifically for this project. Cores removed from the retrofits and other locations around the property were tested for porosity, visually inspected for sealing, and then sliced into one inch sections to determine the vertical porosity profile.
Results showed that the techniques were effective at increasing the overall permeability of the pavement. The most effective retrofit techniques were 6-in core cuts at depths 2-in past breakthrough, increasing local infiltration up to 800 in/hour. Visual inspection and vertical porosity distribution testing confirmed surface sealing, with the average porosity of the top inch significantly lower than porosities at other depths. Sealing was attributed to construction practices and was confirmed as the main distress identified at the location tested. A method was developed to plan retrofit solutions for large areas, either using the linear cut techniques or a core retrofit technique. The recommended depth of any cut retrofit was determined to be 2-in past breakthrough.

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