新拌混凝土水灰比测定方法(英文)

Testing Methods for Determination of Water-to-Cement Ratio of Fresh Concrete-A Short Review

水灰比是决定混凝土品质和耐久性的一个重要参数,因此准确测定新拌混凝土的水灰比对工程实际有着极其重大的意义。本文总结并讨论了文献中报道的新拌混凝土水灰比测定方法。其中微波法是目前为止最简单实用的方法之一,然而其只能测定新拌物中的含水量,需结合其它测定水泥含量的方法才能确定水灰比。电阻率法精度高,但需预先建立水灰比与电阻率之间的关系曲线。其它方法或精度不足,或缺乏现场操作性,从而没有得到广泛的认可。本文对新拌混凝土中水泥含量的测定方法也进行了回顾及讨论。

Water-to-cement ratio is a critical factor determining the quality and durability of concrete. It is thus of great significance to precisely determinate the water-to-cement ratio of fresh concrete during construction. This review summarized some published testing methods for the determination of water-to-cement ratio as to provide a scientific base for the selection and further development of new methods. Among all these methods, microwave method is the simplest and the most practical one. However, it determines only the water content of fresh concrete, and cement content has to be determined in order to calculate water-to-cement ratio. Electrical resis- tivity method has a high accuracy, but it has to establish relationship between water-to-cement ratio and electrical resistivity. Other methods have lack of either accuracy or practicability at the construction site. None of those has gained widespread acceptance for use in the field. Besides, the methods for the determination of cement content in concrete were also discussed.