1、Chapter 3 Structure Materials,Section A Civil Engineering Materials,CONTENT,As an engineer, one must know about the materials used in the construction site. 作为一名工程人员必须知道施工现场所用的建筑材料。It is necessary for an engineer to be conversant with the properties of such materials. 对于工程人员熟悉这些材料的特性是必须的。Civil engin
2、eering materials can be natural and manmade. They contain cement, metals, timber, concrete, bituminous etc. 土木工程材料有天然的和人造的。它们包含水泥，金属，木材，混凝土和沥青等。,CONTENT,Now green civil engineering materials and even eco-materials (n.生态材料)for civil engineering are recommended based on the consideration of sustainabl
3、e development. 现在，基于可持续发展，绿色土木工程材料甚至生态土木工程材料被推荐。This has the benefits of reducing energy, saving resources and protecting the environment, having minimum harm to human health. 这样带来的好处有降低能耗、节约资源、保护环境和最低限度的危害人体健康。,CONTENT,Cement is obtained by burning at a very high temperature a mixture of calcareous
4、 and argillaceous materials. 水泥是石灰质和粘土质材料的混合物在一个很高的温度下被焙烧制的。 Calcined product is known as clinker .焙烧的产品被称为水泥熟料。A small quantity of gypsum is added to the clinker and is pulverized into very fine powder known as cement. 少量的石膏被加入到水泥熟料中然后被粉碎成非常细的粉末称为水泥。,CONTENT,By changing the chemical composition and
5、 by using different raw materials and additives, many types of cements can be manufactured to cater to the need of the construction industry for specific purposes. 通过改变化学组成以及不同原材料、外加剂的使用，来制备不同类型的水泥来迎合有特殊目的的工程建设需求。Rapid hardening cement (快硬性水泥)is used where high strength is required instantly in init
6、ial stages. 快硬性水泥被用在初始阶段有高强度需求的工程中。,CONTENT,Portland pozzolana cement (火山灰质硅酸盐水泥)produces less heat of hydration and offers greater resistance to the attack of aggressive water. 火山灰质硅酸盐水泥的水化热很低同时可以很好地抵抗侵蚀性的水的攻击。Air-entraining cement (引气水泥)is produced by mixing a small amount of an air-entraining age
7、nt with ordinary Portland cement. 引气的水泥通过加入少量的引气剂和普通硅酸盐水泥混合来制备。By adding this, the properties of concrete can be changed and it also increases the frost resistance of hardened concrete. 通过加入引气剂，混凝土的特性被改变，它能够提高硬化混凝土的抗冻性。,CONTENT,Cement is mixed at or near the construction site with sand, aggregate (s
8、mall stones, crushed rock, or gravel), and water to make concrete. 在施工现场，水泥和砂子、骨料（小石头，碎石或砾石）和水混合制成混凝土。 Concrete has a high and its strength depends on the proportion in which cement, and, stones and water are mixed. 混凝土有很高的抗压强度，并且它的强度取决于水泥、石子和水的混合比例。 It hardens with age and the process of hardening
9、continues for a long time after the concrete has attained sufficient strength. 混凝土随着龄期而逐渐硬化，当混凝土已经达到足够的强度后，水化的过程还会持续一段很长的时间。,CONTENT,Normal concrete has a comparatively low tensile strength and for structural applications it is normal practice either to incorporate steel bars to resist any tensile f
10、orces (steel reinforced concrete) or to apply compressive forces to the concrete to counteract these tensile forces (pre-stressed concrete or post-stressed concrete). 普通混凝土有相对较低的抗拉强度，对于结构应用来说，通常的做法是加入钢筋来抵抗拉力的作用（钢筋混凝土）或者是给混凝土施加压力的作用来抵消这些拉力（先张法预应力混凝土或后张法预应力混凝土）。,CONTENT,It is used also for a wide rang
11、e of precast concrete products which include concrete blocks, cladding panels, and pipes. 混凝土也被用在大范围的预制混凝土生产当中，包括混凝土砌块、外挂板和管道。The impact strength, as well as the, of normal concrete is low and this can be improved by the introduction of randomly orientated fibers into the concrete. 普通混凝土的抗冲击强度和抗拉强度是
12、很低的，这可以通过在混凝土中随机引入乱向分布的纤维来提高。,CONTENT,Timber is one of the oldest known civil engineering materials. In addition to its usefulness as a structural material, timber has also fulfilled a role in temporary structures. 木材是最古老的土木工程材料。除了作为结构材料使用外，还能起到临时搭建物的作用。Although timber is a kind of sustainable resou
13、rce, the consumption speed of forests must be slowed down because of the relative slowness of tree growth. 尽管木材是一种可再生资源，但是因为树木的生长相对较慢，因此森林的消耗速度必须减慢。,CONTENT,The requirements for this purpose include ease of working and finishing, good grain pattern and appearance when clear-finished, dimensional sta
14、bility in conditions of variability of temperature and humidity, both internal and external, and resistance to infestation and fungal attack etc. 这个目的的要求包括工作和完成的难易、好的纹理和外观和在温度、湿度、内部和外部变化条件下的尺寸稳定性、抗虫害和真菌的侵蚀等。,CONTENT,Nowadays timber is also playing an important role in falsework carpentry, such as sh
15、uttering for in-situ or precast concrete work, supporting formwork for brick or stone arch or shell forms, or jigs for glued-laminated timber beam or shell forms. 如今，木材在脚手架木工作业中起的作用越来越重要了，如原位立模板，预制混凝土工作，为砖、石拱桥或壳的支模，或是胶合叠层木梁或壳形的夹具等。,CONTENT,The applications of metals in civil engineering are wide and
16、 varied, ranging from their use as main structural materials to their use for fastenings and bearing materials. 在土木工程中，金属材料的应用是越来越广泛，并且种类越来越多，范围从它们用做主要结构材料到连接件和轴承材料。The properties of metals which make them unique among constructional materials are high tensile strength, the ability to be formed into
17、 plate, sections and wire, and the weld ability. 金属具有独特的结构材料性能，如较高的抗拉强度、能被制成钢板、段、电线以及焊接性能。,CONTENT,Other properties of metals are electrical conductivity, high thermal conductivity and metallic luster (金属光泽), which are of importance in some circumstances. 金属的其它特性是导电性、高的导热性和金属光泽，在某些情况下这些特性都是很重要的。Perh
18、aps the greatest disadvantage of the common metals, and steels in particular, is the need to protect them from corrosion by moist conditions and atmosphere. 普通金属特别是钢筋最大的缺点可能是需要保护起来免受来自潮湿条件和大气层的腐蚀。,CONTENT,The importance of metals as constructional materials is almost invariably related to their load
19、 bearing capacity (承载能力)in either tension or compression and their ability to withstand limited deformation without fracture. 对结构材料来说，金属的重要性大多数与它们在抗拉或抗压中的承载能力和抵抗有限的变形而不致断裂的能力有关。It is usual to assess these properties by tensile tests in which the modulus of elasticity (弹性模量), the yield stress (屈服应力),
20、 the tensile strength and the percentage elongation can be determined. 通常采用拉伸试验来评估这些特性，在这个拉伸试验过程中，弹性模量、屈服应力、抗拉强度和伸长率都能通过测试确定。,CONTENT,Steel，basically an alloy of iron and a small amount of carbon，had been made up to that time by a laborious process that restricted it to such special uses as sword bl
21、ades 那时，钢材基本上是由铁里面的合金和一小部分碳通过很费力的加工过程制得的。 Bituminous materials are for the most part in mixtures with mineral or other aggregate. 沥青材料大部分是与矿物或其它骨料混合使用。 Thin coating of bitumen paints or emulsion applied to absorptive materials have the effect of sealing capillaries so that both water and water vapou
22、r are prevented from moving through the materials. 将薄的沥青涂料或乳液应用到吸收材料上，对封闭毛细管有影响，这样水和水蒸气就被阻止通过材料。,EXERCISE,. Fill in the blanks with the information given in the text. 1. Calcined product is known _clinker. A small _of gypsum is added _ the clinker and is pulverized_ very fine powder known as _. 2. I
23、t hardens with _ and the process of _ continues _a long time after the concrete has attained sufficient strength. By virtue _ the ease with fresh concrete in its _may be moulded _any shape it may be used for _ purposes. 3. Other properties of metals are _ conductivity, high _conductivity and _ luste
24、r, which are _ importance in some circumstances.,of,metallic,thermal,electrical,decorative,into,plastic state,of,for,hardening,age,cement,into,quantity,to,as,Chapter 3 Structure Materials,Section B Reinforced Concrete,CONTENT,In many including the Unite State and Canada, reinforced concrete is a dom
25、inant structural material in engineered construction. 在包括美国和加拿大的许多国家，钢筋混凝土在工程结构中是一种主导结构材料。 The universal nature of reinforced concrete construction stems from the wide availability of reinforcing bars and the constituents of concrete, gravel, sand, and cement, the relatively simple skills required i
26、n concrete construction, and the economy of reinforced concrete compared to other forms of construction. 钢筋混凝土结构的特性就是源于钢筋、混凝土、砾石、砂子和水泥这些材料可以很容易获得，以及混凝土工程施工过程中相对简单的技术和与其它结构形式相比的经济性。,CONTENT,As we know, concrete has comparatively low tensile and bending strength compared to its high compressive streng
27、th, and concrete is easy to crack even under a very low stress. 我们都知道，与较高的抗压强度相比，混凝土抗拉和抗弯强度相对较低，甚至在较低的应力作用下，混凝土也很容易开裂。For structural applications it is normal practice to incorporate steel bars to resist any tensile forces. 在结构应用方面，通常的做法是利用钢筋来抵抗拉力。,CONTENT,Steel reinforcement is used in the concrete
28、, can overcome the deficiencies in the tensile and bending strengths of concrete. 钢筋用在混凝土当中，能够克服在混凝土拉伸和弯曲过程中的一些不足。Compared with concrete, the enormous advantage of steel is its tensile strength; that is, it does not lose its strength when it is under a calculated degree of tension, a force which, as
29、 we have seen, tends to pull apart many materials. 与混凝土相比，钢筋的最大优点是抗拉强度；也就是说，它在一定的拉力作用下，钢筋的强度不损失，正如我们看到的，这个拉力能够使得许多材料被拉开。,CONTENT,The useful strength of ordinary reinforcing steels (钢筋)in tension as well as compression, i.e. the yield strength, is about 15 times the compressive strength of common str
30、uctural concrete, and well over 100 times its tensile strength. 在普通的钢筋当中，抗拉强度同抗压强度一样有用，如屈服强度，大约是普通结构混凝土抗压强度的15倍，是它的抗拉强度的100倍。Although steel occupies only a small part of the volume of reinforced concrete (on the average about 2 per cent), it is a major part of the cost. 虽然钢筋只占钢筋混凝土体积的一小部分（大约是2%），它却占
31、据成本的主要部分。,CONTENT,It follows that the two materials are best used in combination if the concrete is made to resist the compressive stresses and the compressive force, longitudinal steel reinforcing bars are located close to the tension face to resist the tension force, and usually additional steel b
32、ars are so disposed that they resist the inclined tension stresses that are caused by the shear force (剪力)in the beams. 如果混凝土被用来抵抗压应力和压力，纵向钢筋被放在受拉力一侧用来抵抗拉力，其它的附加钢筋用来抵抗由剪力引起的斜向拉应力，这样两种材料组合使用最佳，如钢筋混凝土梁。,CONTENT,However, reinforcement is also used for resisting compressive forces primarily where it is
33、desired to reduce the cross-sectional dimensions of compression members, as in the lower-floor columns of multistory buildings (多层建筑). 然而，在一些期望减少截面尺寸的受压构件中，钢筋通常也主要被用来抵抗压力，像用在多层建筑物中的低层柱中。Even if no such necessity exist, a minimum amount of reinforcement is placed in all compression members to safegua
34、rd them against the effects of small accidental bending moments that might crack and even fail an unreinforced member. 即使没有这种必要存在，少量钢筋被用在所有的受压构件中可以保证它们免受小的附加弯矩的影响，这个弯矩能使得构件开裂甚至可能使得无筋构件破坏。,CONTENT,They also complement each other in another way: they have almost the same rate of contraction and expans
35、ion . 钢筋和砼还有另一个互补优势：它们的收缩率和扩张率几乎相同。 Steel rods are embedded in concrete to make reinforced concrete (配筋混凝土，钢筋混凝土)in concrete beams or structures where tension will develop. 钢筋嵌入砼内形成钢筋砼，可用于有拉力产生的砼梁或结构中。 The proper adhesion between the steel and the concrete is of the greatest importance, and bars sho
36、uld be of a sufficiently small diameter to offer an adequate area of contact with the concrete. 砼和钢筋之间也形成很大的黏结力使钢筋不能从砼中滑出,同时，钢筋的直径应该足够地小以提供钢筋与混凝土之间充足的接触面积。,CONTENT,The practical limit is reached when the bars become so numerous that they obstruct the proper placing of concrete. 当钢筋的数量很多时以至于要阻碍混凝土的合理
37、浇注时，此时达到了钢筋直径的合适限值。Concrete and steel form such a strong bondthe force that unites themthat no relative movements of the steel bars and the surrounding concrete occur. 混凝土和钢筋之间形成一种强大的粘合力，这个力能够将它们粘结在一起使得周围混凝土和钢筋不产生相对的滑移。,CONTENT,This bond is provided by the relatively large chemical adhesion which de
38、velops at the steel-concrete interface, by the natural roughness of the mill scale of hot-rolled (热轧)reinforcing bars, and by the closely spaced rib-shaped surface (肋形表面)deformations with which reinforcing bars are furnished in order to provide a high degree of interlocking of the two materials. 这种粘
39、合力是由产生在钢筋混凝土表面的相对较大的化学附着力、热轧钢筋工厂的原始粗糙度以及带肋钢筋表面的间隔较小的变形所提供的，这种带肋钢筋主要是为了使两种材料有很高的联结。,CONTENT,In order to minimize corrosion of reinforcement and consequent spalling of concrete under severe exposure conditions such as in bridge decks subjects to deicing chemicals, galvanized or epoxy-coated (环氧涂层的)reb
40、ar may be specified. 为了减小钢筋的腐蚀和随之而来的混凝土剥落，一些镀锌或环氧涂层钢筋被指定使用。,CONTENT,The steel stress is thus transmitted to the concrete by bond or anchorage , and it is then transmitted to another bar by the same means. 这些钢筋在混凝土中被连接，钢筋应力通过粘合力或锚具传递给混凝土，然后通过同样的方式再传递给另一根钢筋。 The adoption of structural steel and reinfo
41、rced concrete caused major changes in traditional construction practices. 结构钢和钢筋混凝土的应用导致了传统结构做法的重大变革。 In the earlier steel of concrete frame building, the curtain walls were generally made of masonry，they had the solid look of bearing walls (承重墙). 在早期的钢筋混凝土的框架结构，幕墙通常是用石头做成的，它们有承重墙坚实的外观。,CONTENT,Toda
42、y, however, curtain walls (幕墙)are often made of lightweight materials such as glass, aluminum, of plastic, in carious combinations. 然而在今天，幕墙通常是由轻质材料做成的，如玻璃、铝、塑料等不同材料的组合。It was no longer necessary to use thick walls of stone or brick for multistory buildings, and it became much simpler to build fire-
43、 resistant floors. 多层建筑物的建造也不再需要用石头或砖来砌筑厚墙了，同时建造耐火的楼面板也变得很简单。,EXERCISE,. Fill in the blanks with the information given in the text. 1. They also complement each other in another way: they have almost the same rate _ contraction and expansion. 2. Still another advantage is that the steel is therefore
44、 completely surrounded by the _ and the _ does not rust in concrete. Acid corrodes steel, whereas concrete has an _ reaction, the opposite of _. In order to minimize _ of reinforcement and consequent _of concrete under severe exposure conditions such as in bridge decks subjects to _, galvanized or e
45、poxy-coated rebar may be specified.,spalling,deicing chemicals,acid,alkaline chemical,concrete,corrosion,steel,of,EXERCISE,. Translate the following passages from English into Chinese. As the cement hydrates，large amount of ettringite are formedWhen the concrete sets and develops strength, it will b
46、ond to the reinforcement and at the same time start expanding if sufficient quantities of curing water are present. Since the concrete is bonded to steel, its expansion under the restraining influence of the steel will induce tension in the latter while the concrete itself goes into compression. At
47、the end of moist curing, when the element is exposed to drying conditions, it will shrink 1ike a normal Portland cement concrete.,EXERCISE,. Translation answer 水泥水化后，会形成大量的钙矾石。当混凝土凝固，强度开始发展的时候，如果有足够数量的养护水存在的情况下，混凝土将会粘结钢筋，同时开始膨胀。既然钢筋和混凝土粘结在一起，后期，在钢筋的抑制作用下混凝土膨胀将会产生拉力，然而混凝土本身也受压。在潮湿养护的最后，当构件被暴露在干燥的条件下，
48、将会像普通硅酸盐水泥混凝土一样产生收缩。,Chapter 3 Structure Materials,Section C Durability of Concrete,CONTENT,At present, more and more destructive case of engineering due to lack of durability not insufficient strength under all kinds of serious conditions and many new questions companying with the development of co
49、ncrete technology make people pay attention to the durability of concrete. 现今，在各种严酷环境条件下和伴随许多混凝土技术发展新问题的出现，越来越多的由于缺乏耐久性而不是强度不足的工程破坏实例引起了人们对混凝土耐久性的关注。The idea of which concrete should be design according to durability instead of strength was accepted widely. 根据耐久性设计代替强度设计的观点越来越广泛地被人们所接受。,CONTENT,The
50、durability of concrete can be defined as its resistance to deterioration resulting from external and internal causes. 混凝土的耐久性被定义为抵抗外部和内部原因导致的恶化的能力。The internal causes are the effects of salts, particularly chlorides and sulphates in the constituent materials, interaction between the constituent materials, such as alkali aggregate reaction, volume changes, absorption and permeability . 内部原因是盐的影响，特别是氯化物和硫酸盐，以及组成材料之间的相互作用，如碱骨料反应、体积变化、吸水性和渗透性。,
