Minnesota Department of Transportation
This report evaluates the third year performance of the pervious concrete test Cell 64 located in the parking lot/driveway on the south side of MnROAD's pole barn. In this report, a device and procedure to evaluate the drainability of pervious concrete and a threshold for clogging was developed. In addition, the condition of the test cell was determined by Schmidt hammer measurements and distress mapping using the Mn/DOT Pavement Distress Identification Manual. Watermark/thermocouple data was also recorded to measure freeze-thaw cycles. The number of freeze-thaw cycles at discrete depths in the pavement was then compared to impervious concrete test cells at MnROAD. The Mn/DOT and Cemstone petrographic reports on cores that had been taken 4.5 months after construction are also included, although they were outlined in previous reports. It was found that the pervious concrete of Cell 64 experienced less freeze-thaw cycles than impermeable concrete pavements of similar thickness. The main change in surface distress from the first year to the third year of service was the presence of a longitudinal crack that extended the entire cell length and raveling of the top layer of concrete. Initiating at the pole barn at a joint in the concrete curb, the crack could have propagated the length of Cell 64 due to Falling Weight Deflectometer (FWD), traffic, or thermal loading. Knowledge of pervious concrete will be greatly expanded with the study of newly constructed test cells. These cells are Cell 85, Portland Cement Concrete (PCC) pervious on sand and 89, PCC pervious on clay on the MnROAD Low Volume Road.
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