Multiple choice

The width of the expansion joint is 20 mm in a cement concrete pavement. The laying temperature is 20°C and the maximum slab temperature in summer is 60°C. The coefficient of thermal expansion of concrete is 10 x 10–6 mm/mm/°C and the joint filler compresses upto 50% of the thickness. The spacing between expansion joints should be

  1. 20 m

  2. 25 m

  3. 30 m

  4. 40 m
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Expansion joint spacing L = (delta) / (alpha * deltaT). delta = 20mm * 0.5 = 10mm. alpha = 10 * 10^-6. deltaT = 60 - 20 = 40. L = 10 / (10 * 10^-6 * 40) = 10 / 0.0004 = 25,000 mm = 25 m.

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