Joints in concrete construction — identifying the surface between two successive placements The interface where one concrete pour meets the next pour placed later is called:

Introduction / Context:
Joints are deliberately created or naturally formed interfaces in concrete to control cracking, accommodate movement, or sequence construction. Knowing joint types ensures correct detailing and workmanship.

Given Data / Assumptions:

• Two concrete placements are made at different times.
• The interface is prepared (roughened, cleaned, bonded) before the next pour.
• No intentional movement gap is provided at this interface.

Concept / Approach:

A construction joint is formed when concrete placing is stopped and later resumed. It is not intended to open or close like movement joints. Contraction (control) joints intentionally weaken the section to control shrinkage cracking. Expansion joints are full-depth separations to accommodate thermal expansion with filler/sealant.

Step-by-Step Solution:

Verification / Alternative check:

Specifications outline surface prep at construction joints to ensure shear transfer and bond continuity where required.

Why Other Options Are Wrong:

• (a) and (b) are movement-control joints, not simply placement interfaces.
• Combinations in (d) or (e) misclassify joint intent.

Common Pitfalls:

• Failing to adequately roughen and clean the joint → potential cold joint and leakage.

Final Answer:

Construction joint.