A highway is made of concrete slabs that are 15 m long at 20.0 °C.
(a) If the temperature range at the location of the highway is from −20.0 °C to + 40.0 °C, what size expansion gap should be left (at 20.0 °C) to prevent buckling of the highway? (b) How large are the gaps at −20.0 °C?