Editorial

摘要

It is almost a cliche to say that concrete is the world's second most consumed material after water. But it is also a fact that the amount of concrete production worldwide is very large. Although no precise data are available, some estimates suggest that it to be 15 to 20 billion tons per year others say that it could be as high as 25 billion tons per year. What is however true is that the significant increase in the use of concrete is because of two simple reasons: One, concrete contains about 70% rock or aggregates, which is the most abundantly available material on the earth; and two, limestone and clay, which are cement materials, are also amply available, not to speak of water. In fact, it would not be wrong to say that concrete is used for engineering purpose only because it contains aggregates - cement alone is unsuitable for most purposes except for a few special applications.