An isolated concrete pavement slab of length L is resting on a frictionless base. The temperature of the top and bottom fiber of the slab are Tt and Tb, respectively. Given: the coefficient of thermal expansion = α and the elastic modulus = E. Assuming Tt > Tb and the unit weight of concrete as zero, the maximum thermal stress is calculated as

• A. \(\frac{{E\alpha \left( {{T_t} - {T_b}} \right)}}{2}\)
• B. Eα (Tt - Tb)
• C. Zero
• D. Lα(Tt - Tb)