Concrete is probably used more widely than any other substance except water, yet it remains largely unappreciated. “Some people view the 20th century as the atomic age, the space age, the computer age — but an argument can be made that it was the concrete age,” says cement specialist Hendrik Van Oss. “It’s a miracle material.” Indeed, more than a ton of concrete is produced each year for every man, woman and child on Earth. Yet concrete is generally ignored outside the engineering world, a victim of its own ubiquity and the industry’s conservative pace of development. Now, thanks to environmental pressures and entrepreneurial innovation, a new generation of concretes is emerging. This high-tech assortment of concrete confections promises to be stronger, lighter, and more environmentally friendly than ever before.
Concrete is also a climate-change villain. It is made by mixing water with an aggregate, such as sand or gravel, and ce
A. sand or gravel has to be used as an aggregate in the process of mixing.
B. the materials which are used to make concrete are not durable.
C. recycling of concrete is quite difficult when concrete breaks down.
D. chemical reaction in manufacturing cement emits carbon-dioxide world-wide.
| Industrial psychology is the application of various
psychological techniques to the se-lection and training of industrial workers
and to the promotion of efficient working condi-tions and techniques, as well as
individual job satisfaction. The selection of workers for particular jobs is essentially a problem of discovering the special aptitudes and techniques, and personality characteristics needed for the job and of devising tests to determine whether candidates ha A. working efficiency that leads to the highest output B. the working skills and the working environment C. the techniques leading to the highest productivity D. the use of workers to get the greatest profit [单项选择]对无骨端外露骨折伤员的肢体，用夹板或木棍、树枝等固定时应____。（）
A. 超过伤口上、下关节； B. 超过伤口下关节 C. 超过伤口上关节； D. 不得超过伤口上、下关节 [单选题]对液压制动的汽车连续踏几次制动踏板,始终到底且无力是因为( )。
A.制动主缸皮碗损坏、顶翻 B.制动蹄片和制动鼓间隙过大 C.制动系统渗入空气或制动液气化 D.制动液牌号不对 [单选题](2014真题) 中央银行规定提高住房贷款的首期付款比例，属于（）。
A.贷款额度控制 B.消费信用控制 C.间接信用指导 D.证券市场信用控制 [判断题]低压并联电容器装置接线,宜装设谐波含量超限保护、自动投切控制器、保护元件、信号和测量表计等配套器件。( )
A.正确 B.错误 [单项选择]相对热轧而言，冷轧的优点是（）。
A. 表面质量好、尺寸精度高 B. 易于轧制变形 C. 轧制中可采用大的变形量 D. 不产生加工硬化 [单选题]陆钦斯的量杯实验证明的是（ ）现象。
A.变势 B.定势 C.迁移 D.原型启发 [单选题]( )在纪念中华人民共和国宪法公布实行30周年大会上的讲话指出:宪法的生命在于实施,宪法的权威也在于实施。
A. B.李克强 C.胡锦涛 D.温家宝 [简答题](231610)CFB锅炉床压偏低的危害有哪些？(1.0分)
[判断题]数控机床在进行直线加工时,ΔLi直线斜率不变,而两个速度分量比ΔLYi/ΔLXi不断变化。 ( )
A.正确 B.错误 [单选题]对于可能送电至停电设备的（）都应装设接地线或合上接地刀闸（装置），所装接地线与带电部分应考虑接地线摆动时仍符合安全距离的规定。
A.线路侧 B.母线侧 C.各方面 D.负荷侧 [判断题]电缆试验过程中需更换试验引线时，作业人员应先穿好绝缘鞋对被试电缆充分放电。
A.正确 B.错误 [判断题]切断绳索时，应先将预定切断的两边用软钢丝扎结，以免切断后绳索松散，断头应绑扎处理。
A.正确 B.错误 我来回答: 提交
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