当配制水泥混凝土用砂由粗砂改为中砂时，其砂率( )。A．应适_爱下问搜题

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问题单项选择题

当配制水泥混凝土用砂由粗砂改为中砂时，其砂率( )。

A．应适当减小

B．不变

C．应适当增加

D．无法判定

答案

参考答案：A

解析：由粗砂改为中砂，由于中砂的细颗粒含量高于粗砂中的细颗粒含量，为保证原骨料中细集料的含量，应适当减小砂率。

阅读理解

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多项选择题

对于下列情况（）应对变压器进行特殊巡视检查，增加巡视检查次数。

A、气象突变（如大风、大雾、冰雹、寒潮等）时；

B、高温季节、高峰负载期间；

C、雷雨季节特别是雷雨后；

D、新设备或经过检修、改造的变压器在投运72h内。