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| Thermo-Cracking |
by Katy Koch
Cheyenne Elementary, Cheyenne, Oklahoma
(presented at the 1997 EarthStorm Science Fair)
I became interested in how weather
affects our state's highways because my father works for the Oklahoma State Highway
Department. I began my project by meeting with Gary Ridley and Brent Almquist
at Oklahoma Department of Transportation (O.D.O.T.) Division 5 Headquarters on
August 16, 1996. On August 22, Brent Almquist took me to a sight on I-40 to tour
an asphalt plant and watch them put the finishing touches on a section of roadway.
I "surfed" the
Internet for information on the freeze-thaw cycle and found a Canadian teacher's
outline for testing freeze-thaw cycles using common materials. This gave me the
idea for using shale, a fossil rock, to show cracking in roadways in a short
amount of time.
I then put the shale and the core sample (obtained from the O.D.O.T.)
in the freezer overnight and then let it thaw for one day and then repeated this
process for two weeks. After the second week, I looked at the shale and the
core sample for newly formed cracks. I found new cracks on the shale but was
unable to determine if any cracks were on the core sample. I think that if
I left the core longer, there would have been cracks as well.
By visiting with
O.D.O.T. and conducting my own experiments, I found that freeze-thaw is a problem
on our state's roadways. |
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