Core TradesCâu 61 / 700
A slab-on-grade develops a network of random, map-like surface cracks within days of placement, but the cracks are shallow and do not reach the reinforcement. What is the MOST likely cause?
a.Overloading before the concrete gained strength
b.Plastic shrinkage from rapid surface moisture loss
c.Inadequate concrete cover over the rebar
d.Excessive aggregate size in the mix
Giải thích
Shallow, random map-cracking that appears within hours to days is classic plastic shrinkage cracking, caused by surface water evaporating faster than bleed water rises, often in hot, dry, or windy conditions. Overloading produces structural, not surface, cracks. Cover and aggregate size do not create map-pattern surface crazing.
Trích dẫn luật: 2025 CA Building Code, Chapter 19 (Concrete)Luyện miễn phí toàn bộ 700 câu hỏi — không cần đăng ký.
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