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[单选题]
电磁感应法钢筋探测仪(以下简称钢筋探测仪)和雷达仪检测前应采用校准试件进行校准,当混凝土保护层厚度为()时,混凝土保护层厚度检测的允许误差为土1mm。
A.10~30mm
B.10~50mm
C.20~70mm
D.20~80mm
查看答案
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A.10~30mm
B.10~50mm
C.20~70mm
D.20~80mm
A.0.01mm
B.0.05mm
C.0.1mm
D.0.12mm
A.0.5mm
B.0.8mm
C.1.2mm
D.1.5mm
A.7d
B.14d
C.28d
D.56d
A.7天
B.14天
C.28天
D.56天