To avoid low spots when using hand-operated straightedges, workers should ensure there is always enough concrete ahead of the straightedge.

To avoid low spots when using hand-operated straightedges, workers should ensure there is always enough concrete ahead of the straightedge.

• A. There is enough concrete ahead
• B. There is no bleed water ahead
• C. The edge forms are removed
• D. The straightedge is moved rapidly

Answer: (A)

Keeping a continuous supply of concrete ahead of the hand-operated straightedge is essential for a uniform surface. When there isn’t enough concrete in front, the blade tends to ride on the surface and pull material from behind, which can leave low spots and an uneven finish. By ensuring there is always enough concrete ahead, the straightedge can shave off excess material and push a steady layer forward, maintaining a stable plane as the surface is struck off. This approach helps the mat stay fed and reduces the chance of hollow areas forming. The other ideas—no bleed water ahead, removing edge forms, or moving the straightedge rapidly—don’t address maintaining material in front of the blade and can contribute to surface defects.

Keeping a continuous supply of concrete ahead of the hand-operated straightedge is essential for a uniform surface. When there isn’t enough concrete in front, the blade tends to ride on the surface and pull material from behind, which can leave low spots and an uneven finish. By ensuring there is always enough concrete ahead, the straightedge can shave off excess material and push a steady layer forward, maintaining a stable plane as the surface is struck off. This approach helps the mat stay fed and reduces the chance of hollow areas forming. The other ideas—no bleed water ahead, removing edge forms, or moving the straightedge rapidly—don’t address maintaining material in front of the blade and can contribute to surface defects.