水泥混凝土是当今世界上用量最大的建筑材料,1980年其用量约70亿吨。近30年来,国外普遍在专设的工厂里将混凝土预先拌好,再用车辆运到现场使用。这种混凝土是作为一种建材产品出售的,所以称为商品混凝土,也称预拌混凝土。长期实践表明,商品混凝土具有下列优点: Cement concrete is the most used building material in the world today. In 1980 it used about 7 billion tons. In the past 30 years, foreign countries have generally premixed concrete in a special factory and transported it to the scene with vehicles. This concrete is sold as a building material product, so it is called commodity concrete, also known as ready-mixed concrete. Long-term practice shows that commercial concrete has the following advantages: