coefficient of thermal expansion for concrete
i would like to ask for the formula of the coefficient of thermal expasnion for concrete and its parameters.
what is its effect in sog cracking?
thank you and more power.
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(i am referencing my values from the text "concrete 2nd edition" (mindess, young, darwin).)
the thermal expansion coeff. of concrete is estimated from the volumes of aggregate, and cement content. an average value for most rocks is 6 to 8 x 10^(-6)/celcius. the value for cement paste varries depending on the moisture content, w/c ratio, and its age: try 18 to 20 x 10^(-6)/celcius. a very rough average value for concrete is in the range of 7.4 to 13 x 10^(-6)/c. depending on how precise you are trying to determine the thermal expansion of the concrete you are evaluating, you may need to find this or other research/textbooks since the coefficients of thermal expansion is non-linear for these materials.
from asd 9th
coefficient of expansion for 100 degrees
linear expansion
.000055 (fahrenheit)
the effect will be to crack a slab when a temperature drop causes the slab to shrink. proper amount of temperature/shrinkage steel keeps the size of the cracks small, so you get a zillion little cracks instead of one big one. different designers use different approaches. i prefer to use a lot of steel (depending on the length and thickness of the slab, but
#4@18" minimum) and no contraction joints.