Highway straight edges are used to cut and fill concrete surfaces at which orientation to the construction joint?

• A. Right Angles
• B. 45 Degrees
• C. 30 Degrees
• D. Parallel

Answer: (A)

Straight edges in highway finishing are used to create a square, perpendicular interface with the construction joint. By positioning the edge at a right angle to the joint, you establish a clean, true edge that the new concrete surface can meet squarely. This perpendicular alignment makes sealing and joining easier, helps ensure proper transfer of loads across the joint, and reduces the risk of weak edges, laitance buildup, or spalling along the joint. Using angles like 45 degrees or 30 degrees would produce an angled face that doesn’t meet the joint squarely, complicating joint sealing and dowel alignment. Keeping the edge parallel to the joint wouldn’t define a true perpendicular face, which is essential for a durable, well-sealed joint.