Thread: Interstate cement more effecient
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Old 03-28-2012, 10:24 AM   #8 (permalink)
gone-ot
...beats walking...
 
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...steel rails (railroad) have lowest Crr; steel is very smooth.

...concrete has lower Crr than asphalt; conrete is smoother than asphalt.

...asphalt has higher Crr than concrete; asphalt is rougher than concrete.
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