Answer:
0.88 cm
Explanation:
Initial length at 10°c, L = 23 m
Rise of temperature, Δt = 42 - 10 = 32°c
Coefficient of linear expansion of concrete, α = 12 x 10^(-6) per°c
Minimum spacing to be left = α L Δt
[tex]=12\times10^{-6}\times23\times32[/tex]
[tex]=8.832\times10^{-3}m[/tex]
= 8.832 x 10^{-1} cm
= 0.88 cm
Note: I have a chosen a general value of 12 x 10^-6 per deg c for coefficient of expansion of concrete. However, please refer to the value given in your text book and substitute it for an accurate answer.