Question

A high way is built using concrete slabs 12m long at 20°C.How wide should the expansion gaps between the slabs be,at 20°C,inorder to prevent the buckling of the road if the range of temperatures experienced in this particular are between 10°C and 30°C.

Answer 1

Given,

The length of the slab, L=12 m

The initial temperature, T₁=10°C

The final temperature, T₂=30°C

The coefficient of the linear expansion of the concrete is α=12×10⁻⁶ /°C

The change in the length of the slab is given by,

`\Delta L=\alpha L*\Delta T`

Where ΔT is the change in the temperature.

Therefore,

`\Delta L=\alpha L*(T_2-T_1)`

On substituting the known values,

`\begin{gathered} \Delta L=12*10^(-6)*12*(30-10) \\ =2.88*10^(-3)\text{ m} \\ \approx0.003\text{ m} \end{gathered}`

Thus the expansion in the length of the slab in the given temperature range is 0.003 m.

Thus the gap between the slabs should be 0.003 m