how much will the length of a 1.0 km section of concrete highway change if the temperature varies from -15 Celsius in the winter to 41 Celsius in the summer?
2 answers
two 12ft sections of aluminum siding are placed end to end in the outside wall of a house.How large a gap should be atleast 2(0.09in) to keep the pices from contracting each other and buckling.
(a)
Linear coefficient of thermal expansion at 20ºC of concrete
α=12•4•10^-6 (1/ºC)
If the length at 20ºC is 1000 m, then
- at decreasing temperature the length
becomes smaller by
ΔL=L• α•ΔT=1000•12•4•10^-6•[20-(-15)]=0.42 m.
- at increasing temperature the length
becomes larger by
ΔL=L• α•ΔT=1000•12•4•10^-6•[41-20]=0.25 m.
Therefore the lenthg changes by
0.42+0.25 = 0.67 m.
(b) Temperature range ?????
Linear coefficient of thermal expansion at 20ºC of concrete
α=12•4•10^-6 (1/ºC)
If the length at 20ºC is 1000 m, then
- at decreasing temperature the length
becomes smaller by
ΔL=L• α•ΔT=1000•12•4•10^-6•[20-(-15)]=0.42 m.
- at increasing temperature the length
becomes larger by
ΔL=L• α•ΔT=1000•12•4•10^-6•[41-20]=0.25 m.
Therefore the lenthg changes by
0.42+0.25 = 0.67 m.
(b) Temperature range ?????