问题 问答题 简答题

简述早期混凝土塑性收缩裂缝预防

答案

参考答案:

一是选用收缩量较小的水泥,一般采用中低热水泥和粉煤灰水泥,降低水泥的用量。

二是混凝土的干缩受水灰比的影响较大,水灰比越大,干缩越大,因此在混凝土配合比设计中应尽量控制好水灰比的选用,同时掺加合适的减水剂。

三是严格控制混凝土搅拌和施工中的配合比,混凝土的用水量绝对不能大于配合比设计所给定的用水量。

四是加强混凝土的早期养护,并适当延长混凝土的养护时间。冬季施工时要适当延长混凝土保温覆盖时间,并涂刷养护剂养护。五是在混凝土结构中设置合适的收缩缝

阅读理解

My friend, Emma Daniels, spent the summer of 1974 traveling in Israel. During her month-long stay in Jerusalem she often went to a café called Chocolate Soup. It was run by two men, one of whom—Alex—used to live in Montreal. One morning when Emma went in for coffee, while chatting with her new friend Alex, she mentioned that she had just finished the book she was reading and had nothing else to read. Alex said he had a wonderful book she might like, and that he’d be happy to lend it to her. As he lived just above the café, he quickly ran up to get it. The book he handed to Emma just minutes later was Markings, a book by a former Secretary— General of the United Nations (UN).

Emma had never read it, nor had she ever bought a copy. But, when she opened it up, she was floored to see her own name and address inside the cover in her own handwriting. It turned out that the summer before, at a concert back in Montreal, Emma had met a Californian who was in town visiting friends. They decided to exchange addresses, but neither of them had any paper. The man opened up a book he was carrying in his backpack(背包) and asked Emma to write her name and address inside. When he returned to California, he left the book behind in Montreal, and his friend Alex kept it. When Alex later moved to Jerusalem, he took the book along.

小题1:Alex lent Emma the book, Markings,         .

A.to show his friendliness to her

B.to show his interest in reading

C.to tell her about the importance of the UN

D.to let her write her name and address inside小题2:How did Emma feel the moment she opened the book?

A.Pleased.

B.Satisfied

C.Worried.

D.Surprised.小题3:We can learn from the text that the Californian       .

A.met Emma at a concert

B.invited Emma to a concert

C.introduced Emma to his friend

D.left Emma his backpack小题4:Who was supposed to be the first owner of the book?

A.An official of the UN.

B.A coffee shop owner.

C.A friend of the author’s.

D.Alex’s friend from California.

多项选择题