英語翻譯
Building Materials
There are several kinds of buildings,with the most obvious distinction beingcommercial and residential.Commercial buildings vary greatly in size,type ofconstruction,number of stories,and intended use.One-story buildings oftenlook like large boxes on concrete slabs,as this provides maximum floor spaceand minimum structural frame.There are many kinds of residential buildings,varying greatly in style,grandeur,and number of individual residences ineach building.Engineers should appreciate the impact of selecting differentmaterials and different construction methods.They must also understand theimpact materials and methods have on the overall cost of a structure,and onits appearance and life expectancy.The five major building materials are concrete,reinforcing steel,structural steel,wood,and masonry.
Let us begin our discussion of the world's oldest man-made mass-produced construction material--concrete.Picture for a moment the many kinds of structures you have seen in your life built with concrete.Any such list must include highway pavements (Fig.6.1 ),sidewalks,bridge decks,traffic barriers,foundations,building frames ( Fig.6.2),building curtain walls,dams (Fig 6.3),and retaining walls.Most people could take a few minutes and double the list.The point is that concrete is a versatile,workable material with many construction applications.It is not proper to refer to a highway as a "cement pavement" or to a sidewalk as a "cement sidewalk." They are both made of concrete.Cement is one of the ingredients.Aggregate,sand,water,and perhaps additives are the others.
The earliest known use of cement to make concrete dates back to the ancient.
Romans,about 2,000 years ago.They discovered a sand or mineral on Mount.
Vesuvius that was high in silica and alumina,which they used to make cement.