Hardscape & GradingQuestion 56 of 100
A concrete slab for a patio typically includes control joints. What is their function?
a.To add decorative color
b.To create planned weak points so cracking occurs in straight, controlled lines
c.To increase the slab's water content
d.To eliminate the need for a base
Explanation
Control joints are grooved or cut lines that create a deliberate weak plane, so as concrete shrinks and cracks, the cracks form neatly along the joint rather than randomly across the slab. They are usually spaced in feet roughly equal to two to three times the slab thickness in inches. They control, not eliminate, cracking.
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