The Choice Of Building Materia 建筑材料的选择

The Choice Of Building Material

Choosing different building materials for the particular building application is a choice the designers must make .Natural materials ,such as wood ,stone ,and mud brick ,are the oldest building materials but new manufactured materials ,such as hard -burnt bricks and iron products are constantly being developed .

Building materials must have certain physical properties to be structurally useful .Primarily ,they must be able to carry a load ,or weight ,without any permanent change of shape .A second important property of a building material is its stiffness .

Fitness for the intended purpose remains the prime criterion, but cost is often a determining factor .Thus ,the common practice of replacing natural stone with brick and concrete is because of their lower cost .

While choosing materials ,the concern about reducing the amount of energy required for heating and cooling buildings ,and also a preference for materials and building manufacturing processes that require as little energy as possible are major considerations . Relatively cheap raw materials may be expensive to form .For example ,the cost of

the stone used in buildings today is mainly the cost of labor .In contrast ,concrete can be cast into a mole without any cutting .Plastics are in wide use because they can be easily formed into complex shapes at low cost and are easily mass produced .

Another consideration is that a number of materials presently in common use will probably become exhausted some day ,notable some metals and some varieties of stone ,as well as hard wood timber but other materials will replace them .

Masonry

Masonry consists of natural materials ,such as stone ,or manufactured products ,such as brick and concrete blocks The great pyramid in egypt is one of the most spectacular masonry constructions .

Timber

Timber is one of the few natural materials with good tensileproperties .The species of timber most commonly used for

construction

are

fir

,pine

,spruce

and

redwood.hardwoodsare used primarily for interior finishessuch as floors .

Steel

Steel is an outstanding structural material .It has a high

elastic modulus,which results in small deformations under load .The addition of allowing elements results in higher-strength steels .These steels are used effectively in skyscrapers. Concrete

Concrete is a mixture of water ,sand and gravel .Concrete deforms under load in an elastic manner .Concrete is basically a compressive material and has negligible tensile strength .

Reinforced concrete

Reinforced concrete has steel bars that are placed in the concrete to carry tensile forces .These steel bars ,which range in diameter from 0.2 inch to 2.25 inches ,have wrinkles on the surfaces to ensure a bond with the concrete .Reinforced concrete can be molded into innumerable shapes ,such as beams ,colums，slabs and arches ,and is therefore easily adapted to any particula from building. Plastics

Plastics are rapidly becoming important construction materials

because

of

their

great

variety ,strength ,durability and lightness .Aplastic is

a synthetic material which can be molded into any desired shape and which uses an organic substance as a binder.

译文：

建筑材料的选择

为一座建筑选择不同的建筑材料是设计师必须做出的选择。天然材料，如木材、石头和泥砖，是最古老的建筑材料。而现代生产出的建筑材料，如高温烧制的砖和铁制品也正在不断地发展着。

建筑材料为必须具有一些物理特性才能成为可用之材。首先，它们必须能够负载承重而且不会永久变形。第二个重要特性是建筑材料的硬度。

选择建筑材料的主要标准是适用性，但是成本往往是决定因素。因此，由砖和水泥取代天然石材的做法是为了降低成本。

在选择材料时，主要考虑如何减少加热和冷却建筑物时能源的使用，并且偏爱消耗能源较少的建筑材料和建筑工艺。相对廉价的原材料可能在塑造成形的成本很高。例如，现在石头的使用成本主要是劳动力成本。相比之下，混凝土则无须任何切割即可造型。塑料得到广泛使用也是因为它可以低成本地制造成各种复杂的形状并进行规模化生产。

一些目前广泛使用的建筑材料将面临枯竭，尤其是一些金属和各种石材以及硬木木材，但是会有其他材料取而代之。

? 砌体

砌体包括天然材料，例如石头，或加工产品如砖和混凝土。埃及的大金字塔就是世界上最壮观的砌体建筑之一。

?木材

木材是为数不多的天然材料之一，具有良好的抗拉性能。普遍使用在建筑中的木材品种有杉木、松树、云杉和红木。硬木主要用作室内装饰材料，如地板。

?钢材

钢材是非常好的建筑材料。它具有很高的弹性模量，所以在负载下只会轻微地变形。在钢材中加入合金元素会产生高强度钢。这种钢材适用于建造摩天大楼。

混凝土

混凝土是一种水、沙和砾石的混合物。重负荷下混凝土会发生弹性变形。混凝土基本上是一种压缩材料，它的抗拉强度可以忽略不计。

?钢筋混凝土

钢筋混凝土是在混凝土中放置了钢筋从而承受拉力。这些钢筋的直径从0.2 英寸到2.25英寸不等，表面有皱纹，以便确保它和混凝土能成为一体。钢筋混凝土可被塑造成无数形状，如横梁、支柱、平板和拱门，因此适用于建造某种特定形式的建筑。

?塑料

由于其种类多、强度、耐久性和轻盈等特性，塑料正迅速地成为重要的建筑材料。塑料这种合成材料使用有机物质作为黏合剂，可以被塑造成任何需要的形状。

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