A concrete highway is built of slabs 12 m long (20°C). How wide should the expansion cracks be (at 20°C) between the slabs to prevent buckling if the range of temperature is -30°C to +32°C?
change in L = L original * alpha * change in temp
sorry i dont have symbols and stuff
The Attempt at a Solution
I've tried it one way so far.
Basically, I just found the difference between the higher temp and the highway temp, and solved that as one equation. Then i found the difference between the lower temp and the highway temp, and solved that as one equation. Then i added the two answers.
change in L = 12m * 1200e-6(our teacher gave us this for alpha) * (32-20) = .1728
change in L = 12m * 1200e-6 * (20-(-30)) = .72
then i got .8928 cm