Preventing Buckling of Concrete Highway Slabs

How can we prevent the buckling of concrete highway slabs?

Given data: A concrete highway is built of slabs 15 m long with a coefficient of linear expansion for concrete of 1.2 x 10-5 K-1. The temperature changes from -20oC in the winter to 48oC in the summer.

Answer:

To prevent the buckling of concrete highway slabs, we should ensure that there are appropriate expansion gaps between the slabs. In this case, the width of the expansion gaps should be 0.01224 m.

In order to determine the width of the expansion gaps needed to prevent buckling of the concrete slabs, we can utilize the formula for expansion in the length of the slab:

ΔL = L * α * (Tf - To)

Where:

ΔL = expansion in the length of the slab

L = length of the concrete slab = 15 m

α = coefficient of linear expansion for concrete = 1.2 x 10⁻⁵ K⁻¹

To = initial temperature of the slab = -20 °C

Tf = final temperature of the slab = 48 °C

Substitute the values into the formula:

ΔL = (15) * (1.2 x 10⁻⁵) * (48 - (-20))

ΔL = 0.01224 m

Therefore, the width of the expansion gaps between the concrete highway slabs should be 0.01224 m to prevent buckling when the temperature changes from -20oC in the winter to 48oC in the summer.