本篇文章共分 5 段，將工業革命後建築材料的重要變化，從鋼鐵的分類與使用到混凝土成為建材重要成分等一一加以說明陳述。

本篇考題英文原文與對應之中文翻譯整理如下。練習作答解題時若有對語意不清楚之處，請仔細查閱對照，以提升閱讀理解能力。

Building Materials 建築材料

1. 十九世紀前的建築材料

   It is difficult to exaggerate the radical change that the new industrial world of the nineteenth century brought to architectural materials. Since the beginning of architectural history, the same basic substances had been employed. They were provided directly by nature and used in their natural or near-natural state, only cut, shaped, and dried into the functional forms of timbers, stone blocks, and clay bricks. The exceptions were lime mortar and Roman concrete. Metals, which had the tensile strength that masonry materials lacked, were employed in minor and supplementary ways. Bronze was expensive as well as brittle. Iron, the structurally more important metal, was available in limited quantities and uneven quality, and was too easily converted to rust by the elements. It was, therefore, restricted in use to things such as tie-rods and chains, and, along with bronze, to masonry clamps and decoration. Prior to the nineteenth century, the structural presence of iron in architecture was scarcely noticeable.

   十九世紀的新工業世界給建築材料帶來的巨大變化再怎麼誇大也不為過。自建築史開始以來，就一直在使用同樣的基本物質。它們直接由自然界提供，並以其自然或接近自然的狀態使用，只是被切割、塑形和乾燥成木材、石塊和粘土磚的功能形式。石灰砂漿和羅馬混凝土是個例外。金屬具有磚石材料所缺乏的抗拉強度，被用在次要的和補充的方面。青銅很貴，而且很脆。鐵是結構上更重要的金屬，但數量有限，質量也不穩定，而且太容易被大自然轉化為銹蝕。因此，它被限制在諸如拉桿和鏈條等方面使用，並與青銅一起被用於砌築夾子和裝飾。在 19 世紀之前，鐵在建築中的結構性存在幾乎不為人所知。

2. 鐵的分類與使用

   The Industrial Revolution changed all that. Iron materials became available in such large quantities that they could play far more than a minor architectural role. In 1800, the world production of iron stood at 825,000 tons, by 1830 it was 1,825,000 tons, and nearly 40,000,000 in 1900—an increase of almost 50-fold over the century. The growth was not only in quantity, but quality as well. Iron, found bountifully in Earth’s crust as an oxide, is a material of almost protean variability. It is not simply pure or impure, but can be made hard or soft, brittle or ductile, strong or weak. These qualities depend on carbon content, freedom from impurities (slag), and heating and cooling treatments of the refined metal. Traditionally, three versions existed: cast iron, wrought iron, and steel. Cast iron is the crudest form, containing the most impurities and thus being extremely brittle. Wrought iron, because it includes almost no carbon, is highly malleable (hence its name), but also comparatively soft. The optimum material is steel, which incorporates a restricted amount of carbon for hardness but is otherwise free of impurities, giving it great strength, and which, as a result of tempering treatments, is also malleable.

   工業革命改變了這一切，鐵的材料變得如此之多，以至於它們在建築中發揮的作用遠遠超過了一個小角色。1800 年，世界鐵的產量為 82.5 萬噸，到 1830 年為 182.5 萬噸，1900 年接近 4,000 萬噸—一個世紀內幾乎增加了 50 倍。這種成長不僅體現在數量上，也體現在質量上。鐵在地殼中以氧化物的形式大量存在，它是一種幾乎變化無窮的材料，不是簡單的純或不純，而是可以變硬或變軟，變脆或變韌性，變強或變弱。這些品質取決於碳含量、不含雜質（渣）以及精煉金屬的加熱和冷卻處理。傳統上，存在著三種版本：鑄鐵、鍛鐵和鋼。鑄鐵是最粗糙的形式，含有最多雜質，因此非常脆。鍛鐵，因為它幾乎不含碳，所以可塑性強（因此而得名），但也相對較軟。最理想的材料是鋼，它含有一定量的碳以提高硬度，但在其他方面沒有雜質，使其具有很強的強度，並且由於回火處理的結果，它也具有可塑性。

3. 煉鐵的進步

   Cast and wrought iron came into prodigious manufacture in the early and mid-nineteenth century as a result of rapid growth in demand, new means to transport materials, and more efficient iron-founding techniques. But the mass production of steel required further technological innovations to rid the metal of weakening impurities and to control more perfectly the amount of carbon added. Such advances were made with the Bessemer process (put into use in 1860) and the open-hearth process of 1864, scientific iron metallurgy in the last third of the century perfected these techniques.

   在 19 世紀早期和中期，由於需求的快速增長、新的材料運輸方式和更有效的煉鐵技術，鑄鐵和鍛鐵開始大量生產。但是，鋼鐵的大規模生產需要進一步的技術革新，以去除金屬中的弱化雜質，並更完美地控制碳的添加量。貝塞麥工藝（1860 年投入使用）和 1864 年的明火工藝取得了這樣的進步，本世紀最後三分之一的科學煉鐵術使這些技術精益求精。

4. 鍛鐵與鋼

   A significant but little-known fact is that the main form of increased steel production was technically not steel but a kind of wrought iron. It lacked a crucial property of true steel—its hardening power—yet it differed from the older forms of wrought iron because it was free from the weakening presence of slag, at the same time being malleable (unlike cast iron). It was called steel only because the name carried the status of a high-quality and high-priced product.

   一個重要但鮮為人知的事實是，從技術上講，增加鋼產量的主要形式不是鋼，而是一種鍛鐵。它缺乏真正的鋼的一個關鍵屬性—它的硬化能力—但它與舊形式的鍛鐵不同，因為它沒有熔渣的削弱作用，同時具有可塑性（不像鑄鐵）。它被稱為鋼，只是因為這個名字帶有高質量和高價格產品的地位。

5. 混凝土的特性與使用

   Another alternative new building substance was concrete, composed of an aggregate of broken stone, gravel, or other small chunks of hard matter embedded in a matrix of lime, sand, and water. First used in Roman times, its modern revival depended on the invention of portland cement in 1824, a substance of many times greater strength, durability, and fire resistance than ancient lime cement. Mass-produced concrete began to come into widespread use in the 1850s and 1860s, in the construction of the sewers of Paris, for example. However, even with portland cement, the use of concrete was still severely restricted by its low tensile strength, but the remedy was at hand in the newly available iron and steel; their properties complemented those of concrete. The latter material was cheap, easily molded into large structural forms with great compressive but little tensile strength. Iron and steel, on the other hand were expensive, difficult to shape, yet endowed with extreme tensile strength and easily procurable in the simple form of long, thin bars.

   另一種新的建築材料是混凝土，由碎石、礫石或其他小塊硬物的集合體組成，嵌入石灰、沙子和水的基質中。最早用於羅馬時代，它的現代復興取決於 1824 年波特蘭水泥的發明，這種物質的強度、耐久性和耐火性比古代石灰水泥大很多倍。大規模生產的混凝土在 19 世紀 50 年代和 60 年代開始廣泛使用，例如，在巴黎的下水道建設中。然而，即使有了波特蘭水泥，混凝土的使用仍然受到其低抗拉強度的嚴重限制，但補救措施就在新出現的鐵和鋼中；它們的特性與混凝土的特性相輔相成。後一種材料很便宜，很容易被塑造成大型的結構形式，具有很強的抗壓強度，但抗拉強度很小。另一方面，鐵和鋼價格昂貴，難以成型，但具有極強的抗拉強度，而且很容易以簡單的細長條形式採購取得。