Question

. A concrete highway is built of slabs 12 m long (20°C). How wide should the
expansion cracks between the slabs be (at 20°C) to prevent buckling if the range of
temperature is -30°C to +50°C?

Answer 1

Expansion occurs when

$$T>20°C$$

The expansion:

$$\Delta l=\alpha l (T-T_0)$$

$$\Delta l=(12\cdot 10^{-6})(12) (50-20)=0.00432 \ m$$

The expansion cracks between the slabs should be not less than 4.32 mm.