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1、河 北 理 工 大 学 毕 业 设 计 中 英 文 翻 译英汉翻译Construction materials1 Concrete1.1 Properties and Uses of Normal ConcreteConcrete is a man-made composite the major constituent of which is natural aggregate (such as gravel and sand ) and binding medium (such as cement paste, bitumen and polymers ). The binding med

2、ium is used to bind the aggregate particles together to form a hard composite material.In its hardened state concrete is a rock-like material with a high compressive strength. By virtue of the ease with which fresh concrete in its plastic state may be moulded into any shape it may be used for decora

3、tive purposes.Normal concrete has a comparatively low tensile strength Concrete is also used in conjunction with other materials, for example, it may form the compression flange of a box section and the remainder of which is steel (composite construction ). Concrete is used structurally in buildings

4、, shell structures ,bridges. sewage-treatment works , railway sleepers , roads , cooling towers, dams, chimneys. harbours, off-shore structures, coastal products which include concrete blocks, cladding panels, pipes and lamp standards.The impact strength, as well as the tensile strength, of normal c

5、oncrete is low and this can be improved by the introduction of randomly orientated fibers into the concrete. Steel , polypropylene, asbestos glass, carbon and even wood fibers have all been used with some success in precast products and in-situ concretes, including pipes,building panels and piles.Co

6、ncrete requires little maintenance and has good fire. Concrete hasother properties which may on occasions be considered less desirable, for example, the time-dependent deformations associated with drying shrinkage and other related phenomena.1.2 Preparation of Normal Concrete1河 北 理 工 大 学 毕 业 设 计 中 英

7、 文 翻 译We can learn how a structural concrete is prepared form Fig.3.3.Curing after the placing of concrete is very important for obtaining good properties.Making good concrete is difficult without addition of plasticizers or superplasticizers. Good concrete has to be satisfactory in its hardened sta

8、te(i.e. needed strength and good durability) and also in its fresh state while being transported from mixers and placed in formworks(sometimes through pumping).1.3 Constituents in Concrete and Their Basic KnowledgeConcrete is composed mainly of there materials, namely, cement, water and aggregate, a

9、nd an additional material known as a chemical admixture, is sometimes added to modify certain of its properties. Fly ash ground blast-furnace slag powder and silica fume are often used to replace partial cement to modify the properties of concrete and reduce the cost of concrete.A typical structure

10、of hardened concrete and the proportions of constituent materials encountered in most concrete mixes are shown in Fig.3.4. In a properly proportioned and compacted concrete the voids are usually less than 2%. The properties of concrete in its fresh and hardened state can show large variations depend

11、ing on the type quality and proportions of the constituents.（1） CementThe different cements used for making concrete are finely ground powders and all have the important that when mixed with water a chemical reaction(hydration) takes place. This in time produces a very hard and strong binding medium

12、 for aggregate particles. In the early stages of hydration, cement mortar gives fresh concrete its cohesive properties.（2） AggregateAggregate in concrete can be classified as coarse aggregate and fine aggregate according to its diameter. The diameter of the coarse and fine aggregate is larger than 5

13、mm and smaller than 5mm respecter of the coarse and fine aggregate used in concrete is often cobblestone and crushed gravel and the fine aggregate is river sand andmountain sand.Aggregate is much cheaper than cement andum economy is obtained by2河 北 理 工 大 学 毕 业 设 计 中 英 文 翻 译using as much aggregate as

14、 possible in concrete. Its use also considerably improves both the volume stability and the durability of the resulting concrete. The physical characteristics and in some cases the chemical composition of aggregate affecting to a varying degree on the properties of concrete in both plastic and harde

15、ned state.Sand is generally considered to have a lower size limit of about 0.08mm and a little less. Materials which size is smaller than 0.08mm is classified as clay which does harm to the mechanic properties and durability of concrete.Sea sand is not permitted to be used for making structural conc

16、rete before decreasing its salt content to less than 0.6% by washing.（3） WaterIn general water fit for drinking , such as tap water , is acceptable for mixing concrete . The impurities that are likely to have an adverse effect when present in appreciable quantities include silt, clay, alkali, and ot

17、her salts , organic matter and sewage.The use of seawater does not appear have any adverse effect on the strength and durability of Portland cement concrete but it may cause surface dampness. Efflorescence and staining and should be avoided where concrete with good appearance is required. Seawater a

18、lso increases the risk of corrosion of steel and its use in reinforced concrete is not permitted.（4） Chemical admixturesChemical admixtures are chemical substances introduces into a batch of concrete, during or immediately before its mixing, in order to alter or improve the properties of the fresh o

19、r hardened concrete or both.Nowadays, there are more than 15 types of chemical admixtures produced and they benefit concrete structures in many ways. Since chemical admixtures may also have detrimental effects, their suitability for a particular concrete should be carefully evaluated before use, bas

20、ed on a knowledge of their main active ingredients, on available performance data and on trial mixes.（5） Mineral admixturesFly ash, slag power and silica fume can used to replace a part of cement to reduce3河 北 理 工 大 学 毕 业 设 计 中 英 文 翻 译concrete cost and enhance concrete properties, especially its dur

21、ability. Nowadays, chemicals admixture and mineral admixture have become the two necessary raw materials for preparation of High-performance Concrete, the fluidity and durability of which is both much better than that of normal concrete.1.4 Concrete Mix DeignWhile designing a concrete mix proportion

22、, the following factors must be carefully considered.1) Workability of the fresh concrete;2) Strength of the hardened concrete;3) Durability of the concrete;4) Cost of the concrete.Because of its complication, it should be noted that the concrete mix Proportion designed should be tested and modified

23、 before being used in practice.2 Bituminous Materials2.1 Kinds of Bituminous Materials and Their Main PropertiesEngineers have made use of excellent durability and adhesive properties of bituminous materials. The bituminous materials used in ancient times were natural occurring bitumen. However, the

24、 bulk of todays bituminous materials include bitumen and tar. Bitumen is obtained by the fractional distillation of petroleum (crude oil). It is a viscous liquid or a solid, consisting essentially of hydrocarbons and their derivatives, which is soluble in carbon disulphide, is substantially nonvolat

25、ile and softens gradually when heated. It is black or brown in color and possesses waterproofing and adhesive properties.Tar is a viscous liquid, black in color, with adhesive properties, obtained by the destructive distillation of coal, wood, shale, etc. No specific source is stated and it is impli

26、ed that the tar is obtained from coal.All bituminous materials are for the most part in mixtures with mineral or other aggregate.Bituminous material have the following properties and advantage:1)relativecheapness and availability in large quantities; 2)durability; 3)good adhesive and4河 北 理 工 大 学 毕 业

27、 设 计 中 英 文 翻 译waterproofing qualities; and 4)the ease with which they can be handled at elevated temperatures, but quickly become stiff and resistant to deformation at normal temperatures.2.2 Uses of Bituminous MaterialThe earliest known uses of bitumen and tar relate to hydraulic uses, for example,

28、 bitumen is used to waterproof a building floor. Thin coating of bitumen paints or emulsions applied to absorptive materials have the effect of sealing capillaries so that both water and water vapour are prevented from moving through the materials.Bitumen and tar is a good material of chemical-attac

29、k. It can also bepainted on to parts which are liable to corrosion by weather or other sources.Nowadays the main use of bitumen is in road surfaces, named bitumen concrete road. In order to improve the strength of bituminous material at the high temperatures and the toughness of them at temperatures

30、 below zero, polymer modified bitumen, such ad SBS rubber modified bitumen and APP plastics modified bitumen is widely used.As with most oily substances, bitumen and tars will burn if they are not enough and there is air present. There are two temperatures which are very important for engineers to a

31、void to safely use bituminous materials. There are called the “flash point” and the “fire point”.3 SoilsEvery work of construction in civil engineering is built on soil or rock and in many instances these are also the raw materials of construction. So questions about the properties of soil are as im

32、portant as those about the properties of soil are as important as those about other constructional materials.These questions include:1) Will a given soil provide permanent support for a proposed building?2) Will a given soil compress (or swell) due to application of load from a proposed building, an

33、d by what amounts, and at what rates?3) what will be the margin of safety against failure or excessive or unequalcompression of the soil?5河 北 理 工 大 学 毕 业 设 计 中 英 文 翻 译4) Are natural or constructed soil slopes stable or likely to slide?5) what forces is exerted on a wall when a given soil is packed a

34、gainst it?6) At what rate and to what pattern will water flow through a soil?7) Can a given soil be improved in any way by treatment or admixture?All these require an understanding of soils as materials and of the mechanics of materials. Absolute answers are unobtainable and the engineers have to pr

35、actice the art as the science of geotechnologe.Anyway, to learn about the stabilization and strengthening measures of soil is very important for civil engineering students.In the wider sense, soil stabilization and strengthening measures are terms used for improvement of soils either as they exist i

36、n-situ or when laid and densified as fill. The purpose of stabilization is to make a soil less pervious, less compressible or stronger, or all of stabilization is to make a soil less pervious, less compressible or stronger, or all of these. This is often achieved by injecting a gelling or hardening

37、fluid into the pore spaces in soil. In suitable soils stabilization may also be achieved by introducing admixtures and then applying mechanical work or vibration o densify the materials.4 PolymerA polymer is a large molecule containing hundreds or thousands of atoms formed by combining one, two or o

38、ccasionally more kinds of small molecule (monomers) into a chain or network structures. The polymer materials are a group of carbon-containing (organic) materials which have macromolecular structures of this sort. The main polymer materials which have macromolecular structures of this sort. The main

39、 polymer materials which are widely used in civil engineering are PE (polyethylene), PP (polypropylene) , IR (polyisoprene rubber) , PVC (poly (vinyl chloride), CPVC(chlorinated poly(vinyl chloride) and ABS(acrylonitrile-butadiene-styrene copolymer )etc.In the last 30 years, polymers have secured a

40、place alongside ms and ceramicas one of the major classes of manufactured materials. There are now a great variety ofsuch materials based on about fifty individual synthetic polymers, and they find wide6河 北 理 工 大 学 毕 业 设 计 中 英 文 翻 译application throughout manufacturing industry and engineering. These

41、 materials have aspread of engineering properties which are very different from those found in msand ceramics and a distinct manufacturing and processing technology centered largely on moulding, extrusion and fiber-forming operations.Building construction is one of the main volume markets for polyme

42、rs. However the use of polymers in civil engineering is less conspicuous, because these materials donot generally compete directly with the traditional load-bearing materials, thestructural ms, concrete and masonry. But a number of polymers have important andestablished civil engineering uses. One o

43、f the most straightforward and prominentapplications is in pipework (Fig.3.5) , where longer established materials like cast iron,heavy clay and concrete face severe competition withPolymers also play important roles as surface coatings,several polymer materials.membranes, adhesives andjointingcompo

44、unds,roofingmaterials,claddingsandthermalinsulators.Fiber-reinforced plastics play a great role in light structures. PVC doors and PVC windows have been widely used in the buildings (Fig.3.6). They are light in weight and their thermal insulation and air impermeability are much better than wooden or

45、 m doors/windows.5 Bricks and BlocksThe value of small building bricks or blocks has been recognized, in one form or another, for many centuries. Large manufacturing processed are used in the brick and block-making industries today although clay bricks are still by hand in many parts of our country.

46、Clay, calcium silicate and concrete products all include both bricks and blocks. The distinction between the two is primarily the size, i.e. blocks being larger than bricks. Clay and calcium silicate bricks and concrete blocks are widely used.All bricks and blocks have broadly similar uses although

47、their properties differ in some important respects depending on the raw material used and the method of manufacture.The use of common clay bricks is no longer permitted in large cities in Chinatoday because the manufacture of them will destroy arable land and seriously pollute7河 北 理 工 大 学 毕 业 设 计 中

48、英 文 翻 译air. The main recommended bricks and blocks in buildings are perforated clay bricks,hollow bricks, autoclaved lime-sand bricks, calciumconcrete blocks and foamed concrete blocks etc.silicatebricks,gas-entrained8河 北 理 工 大 学 毕 业 设 计 中 英 文 翻 译材料1 混1.1 普通混的使用和特性的复合材料，主要成分是天然物(如砾石、砂)和约束混是一种人造(如水泥浆

49、、沥青和聚合物)。这种物质具有约束力,是聚合物微粒凝结形成一个硬颗粒复合材料。混是一种强度象硬石状的物质，抗压强度高。新鲜的混具有可塑性高的优点，可造就成任何形状，可用于装饰目的。普通混具有比较低抗拉强度，混也配合其他材料使用。例如，可以组成一个压缩框，其余的部分是钢(复合)。混结构的物使用,壳结构桥梁。污水处理厂、露宿铁路、公路、水塔、水坝、烟囱。港口、离岸结构, 具体包括石块、覆面板、管、装支柱灯。影响机注重 了一些混,以及抗拉强度、不同混强度低，这是正常的，具体可以采用随的混。钢、聚丙烯、石棉、碳、木材甚至在的和预制原址，包括水管、板桩。要求有良好的耐火极限、少维修. 混的其他情况,看起

50、来就较理想,例如，取决于时间与干燥收缩变形等现象有关.1.2 普通混的编制我们可以学习如何具体结构形式 fig.3.3 后准备将是非常重要的具体获得良好特性。没有添加可塑或超可塑剂制作混是非常的。好的混有良好的令人满意的状态(即需要良好的和耐久性),并在搅拌机搅拌后，放入框架(有时通过水管)。1.3 混的组成和基本知识混的主材料有：水泥、水聚合,增加了化学物质称为产物，有时加入一些其他的物质。地面飞灰、炉渣炉硅石粉和油烟常被用来取代部分水泥产业的修改和降低混的成本。硬化混的典型结构和混合物中材料比例由图 3.4 给出。 在适当的比例和压缩情混的间隙通常不到 2%。在未硬化与硬化的情，混的性质会

51、由于类型、质量和混合比例的不同而产生大的变化。1.3.1 水泥用于生产混的不同的水泥是是很好的材料，当与发生化学反应(水化)时，都是很重要的成分。 这时候,为骨料结构提供了强烈的约束力。 在水化早期，谁泥砂浆在混1.3.2 骨料中表现出它的凝聚力。混的骨料可以分为粗骨料和细骨料。粗骨料和细骨料的直径相差总计不大于 5mm 和小于 5mm。使用在混是沙石。中的粗骨料经常是卵石和砾石，而细骨料则因为骨料的价格比水泥的便宜，所以的混是尽可能多的使用骨料。9河 北 理 工 大 学 毕 业 设 计 中 英 文 翻 译骨料的使用量也可以大大提高混的稳定性和耐久性。在某些情的物理特性和化学组成，在不同程度上

52、影响混的整体性能和硬两种具体情况。沙一般认为最低限直径为 0.08mm。直径小于 0.08mm 的粘土，对混的机械特性和耐久性是有害的。在降低海沙的含盐量小于 0.6%之前，海沙是不能用于建造混1.3.3 水的。一般适合饮用的水，如自来水，可以用来调制混。 当出现在可见情，包括：泥沙，淤泥，酸，碱和其它的盐，有机物和污水，杂质很可能产生不良影响。利用海水对水泥混的耐久性和强度没有太大的不良影响，但可能导致表面潮湿，开裂，变色。当混对外观有较高要求时，应尽量避免使用海水。海水的使用也增加了钢的侵蚀并且钢筋混1.3.4 化学外加剂中部使用。化学外加剂是在混合之前或混合时加入混中的化学物质，为了改变

53、或增加混的某些性能。目前，有 15 种以上的化学外加剂,并从各种方面来加强混化学外加剂也有不利影响，在使用钱应该仔细评估其对混的结构。 由于的适应性，基于对主要有效能数据和提供试用的知识。1.3.5 矿物外加剂粉煤灰、炉渣、硅酸盐可代替部分水泥用于降低成本和提高的混的性能,尤其是耐用性。目前,化工、矿产其间包含两个必要的原料，其对高性能混耐久性和性有较大提高。的1.4 混当制定了混混合设计的混合比例时,要慎重考虑以下因素：1) 新混2) 混3) 混4) 混的工作性能; 的最大强度; 的耐久性;的费用.由于其复杂性,在使用前混2 沥青材料的混合比必须被检验和证明。2.1 各类沥青材料及其主要特性

54、工程师利用具有优良性能的粘合剂和具有耐久性的沥青材料. 沥青材料使用的是天然古代块煤.不过,今天大部分的沥青材料,包括沥青和木焦油. 沥青是石油蒸馏取得的(原油).粘度是液体或固体,主要是碳氢化合物及其化合物,可溶性碳水化合物,逐渐加热、软化. 呈现出黑色或褐色,具有防水、粘合性的特点. 沥青是液体粘稠、黑色的粘合剂，其特性类似于蒸馏煤炭、木材等。没有任何特性暗示沥青来自煤炭.所有沥青材料大多以混合物形式，与其他矿物混合.沥青材料的特性,具有以下优点:1)相对便宜且廉价; 2)耐久性; 3)良好的混合剂和防水剂;4),可以很方便地低温处理,在正常温度下很快强.，抗变形性能10河 北 理 工 大

55、 学 毕 业 设 计 中 英 文 翻 译2.2 沥青材料的使用最早使用沥青焦油是用于防水，例如沥青用于防水. 油漆、涂料的分散剂应用沥青材料来吸收末梢,使水蒸气将无法透过材料.沥青焦油是一个很好的沥青化和物质.他可以用于地上有可能腐蚀的情。目前主要是使用沥青路面，即所谓的沥青混道路. 为了提高沥青物质强度，在高温下的韧性,他们在零下温度、修改沥青聚合物,修改 SBS 橡胶沥青使沥青普遍适用.跟大多数含油物质燃烧一样,如果不是有足够的燃烧空间和温度，工程师应避免采用沥青材料，该温度有被称为"热点"、"着火点".3 土壤每个土木工程建设工作是建立在土壤和岩石

56、上，许多情,这些也是的原材料.土壤的特性问题与其他题包括:材料的特性问题具有同等重要的地位。这些问1)对于某筑土体可提供的物理参数是多少2) 某一土壤压缩(膨胀)性是多少3) 安全沉降量是多少4) 天然土坡的失稳条件是什么5) 挡土墙的反力强度是多少6) 以什么方式、在什么速度下水流通过土壤7)土壤性能的方法所有这些都需要一个对土壤力学材料性能的认识， 和实践的科学中得到。是绝对不能从工程师无论如何,土木工程的学生巩固和加强对土壤知识的学习是非常重要的.在广义上的措施,稳定和加强土壤并进行改良土壤条件是可行的,因为他们可以在原址上进行。目的就是要以较少的投入稳定土壤.这往往是通过注射一种硬化液

57、体流出或进入土壤孔隙空间.较稳定的土壤,可以用机械振动。4 聚合物聚合物是一种原子的结合物，形成一个、两个或种小的成链网状结构.高材料的碳化合物，主要类似高聚合物材料的结构. 主要高材料,广泛应用于土木工程是 PE(聚乙烯)、PP(聚丙烯)、IR(橡胶)、聚氯乙烯(乙烯基氯)、CPVC(氯化理),ABS(丙烯-丁二烯-苯乙烯共聚物)等. 在过去 30 年中,取得一席之地聚合物与金属、陶瓷的一大类材料的. 现在有很多基于这种材料高五十个人,发现整个业的广泛应用和工程.这些材料具有特性,设计不同的发现不同的陶瓷的生产和技术,主要集中在浇铸、挤出、形成.是聚合物集合.使用聚合物土木工程是那么明显,因为这些材料一般不同传统承重材料直接竞争,像金属结构、混及砖石.。但也有一些重要的聚合物在土木工程中有重要用途. 其中最突出的应用是管道(fig.3.5),类似铸铁材料,重粘土和一些混与高材料严峻的竞争. 聚合物材料表面也发挥着重要的桥梁作用、薄膜、粘合剂和化合物、建材、绝缘体和热爟.增强结11河 北 理 工 大 学 毕 业 设 计 中 英 文 翻 译构发挥了重要作用. PVC门