Question

The width of expansion joint gap is 2.5 cm in a cement concrete pavement. If the temperature is ${20}^{\circ }$ (and maximum slab temperature in summer is ${54}^{\circ }C$ then the spacing between expansion joints will be _____ m
[Assume coefficient of thermal expansion of concrete as $17\times {10}^{-6}pe{r}^{\circ }C$ ]

Answer 1

Given,
$T_1={20}^{\circ }C$
$T_2={54}^{\circ }C$
The joint filler is assumed to be compressed upto 50% of its thickness
$\therefore {\delta }^{\prime }=\frac{\delta }{2}=\left(\frac{2.5}{2}\right)=1.25cm$

${\delta }^{\prime }=L_e\alpha (T_2-T_1)$

$\Rightarrow 1.25\times {10}^{-2}=L_e\times 17\times {10}^{-6}\times (54-20)$

$L_e=\frac{1.25\times {10}^{-2}}{17\times {10}^{-6}\times (54-20)}$

$=21.63m$