Concrete pavements – sources of tensile stress In rigid (cement concrete) pavements, tensile stresses are generated due to which of the following influences?

Introduction / Context:
Rigid pavements behave like slabs on grade. Unlike flexible pavements, load and environmental actions produce tensile stresses that govern thickness, joint layout, and reinforcement requirements. Recognizing all significant sources of tension is essential for durable design.

Given Data / Assumptions:

• Unreinforced or lightly reinforced concrete slab on subbase/subgrade.
• Wheel loads, thermal gradients, and temperature change considered.

Concept / Approach:
Tensile stress arises from bending due to wheel loads, thermal warping due to temperature differentials through the depth (top hotter or colder than bottom), and uniform temperature drops leading to slab contraction restrained by friction at the interface.

Step-by-Step Solution:
Under wheel loads, interior, edge, or corner loading causes bending tension at critical fibers.Daily temperature cycles create top–bottom gradients → warping stresses.Seasonal or diurnal cooling contracts the slab; restraint by subbase friction induces tensile stress.Hence, all listed mechanisms contribute tensile stresses.

Verification / Alternative check:
Design charts and methods (e.g., Westergaard-type approaches) include load stress and temperature stress combinations.

Why Other Options Are Wrong:
Singling out only one mechanism underestimates slab tension; concrete cracking risk is a combination effect.

Common Pitfalls:
Ignoring curling/warping; misplacing joints that fail to relieve contraction; neglecting base friction in calculations.

Final Answer:
all the above