土木工程专业英语(苏小卒)课文翻译3~5单元.docVIP

Unit 3 (从第三段开始) 现代水泥发明于1824年，称为波特兰水泥。它是石灰石和粘土的混合物，加热后磨成粉末。在或靠近施工现场，将水泥与砂、骨料（小石头、压碎的岩石或砾石）、水混合而制成混凝土。不同比例的配料会制造出不同强度和重量的混凝土。混凝土的用途很多，可以浇筑、泵送甚至喷射成各种形状。混凝土具有很大的抗压强度，而钢材具有很大的抗拉强度。这样，两种材料可以互补。 They also complement each other in another way: they have almost the same rate of contraction and expansion. They therefore can work together in situations where（在…情况下） both compression and tension are factors（主要因素）. Steel rods（钢筋） are embedded in（埋入）concrete to make reinforced concrete in concrete beams or structures where tension will develop（出现）. Concrete and steel also form such a strong bond - the force that unites（粘合） them - that the steel cannot slip（滑移） with the concrete. Still（还有） another advantage is that steel does not rust in concrete. Acid（酸） corrodes steel, whereas concrete has an alkaline chemical reaction, the opposite of acid. 它们也以另外一种方式互补：它们几乎有相同的收缩率和膨胀率。因此，它们在拉、压为主要因素时能共同工作。在出现拉力的混凝土梁或结构中，将钢筋埋入混凝土而成钢筋混凝土。混凝土与钢筋形成如此强大的结合力——这个力将它们粘合在一起——以致于钢筋在混凝土中不会滑移。还有另一个优势是钢筋在混凝土中不会锈蚀。酸能腐蚀钢筋，而混凝土会发生碱性的化学反应，与酸相反。 The adoption of structural steel and reinforced concrete caused major changes in traditional construction practices（施工作业）. It was no longer necessary to use thick walls of stone or brick for multistory buildings, and it became much simpler to build fire-resistant floors（防火地面）. Both these changes served to（有利于） reduce the cost of construction. It also became possible to erect（建造）buildings with greater heights and longer spans. 结构钢与钢筋混凝土的采用使传统的施工作业发生了明显的变化。对多层建筑，再也没必要采用厚的石墙或砖墙，且施工防火地面变为容易得多。这些变化有利于降低建筑的成本。它也使建造高度更高和跨度更大的建筑物成为可能。 Since the weight of modern structures is carried（承受） by the steel or concrete frame, the walls do not support the building. They have become curtain walls, which keep out the weather and let in light. In the earlier steel or concrete frame building, the curtain walls were generally made of masonry; they had the solid look of bearing walls（承重墙）. Today, however, curtain walls are often made of lightweight materials such as glass, aluminu