To prevent transverse cracking problems due to temperature variations in plain jointed concrete pavement, you would like to limit the maximum curling stress at 300 psi. You estimate that the maximum temperature difference between the top and bottom of a 12-in slab will be 30 ^o F with a linear distribution. For 1-ft slab width, determine the maximum allowed transverse joint spacing.

Concrete coefficient of thermal expansion: 5 microstrain / ^o F

Modulus of elasticity of concrete: 4 million psi

Poisson’s ratio of concrete: 0.15

Modulus of subgrade reaction: 300 psi/in