Core TradesQuestion 72 of 700
A driveway slab cracks in a fairly straight line directly over a buried utility trench that was backfilled. The MOST likely cause is:
a.Too much cement in the mix
b.Excessive air entrainment
c.Differential settlement of poorly compacted trench backfill under the slab
d.Curing the slab too long
Explanation
A crack tracking a backfilled trench indicates the subgrade settled unevenly because the trench backfill was not compacted to match the surrounding soil, leaving the slab unsupported over the trench. Cement content, air entrainment, and extended curing do not create a crack that follows a trench line.
Law Reference: 2025 CA Building Code, Chapter 19 (Concrete)Practice all 700 questions free — no signup required.
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