BS 812-109:1990 PDF

This British Standard, a part of the BS 812 series, describes the following three methods for the determination of the moisture content of aggregates: a) oven-drying method (definitive method) b) high temperature method c) microwave-oven method for fine aggregate only. In the case of the definitive, oven-drying method for the determination of the moisture content, only editorial changes have been made to the procedure described in the previous edition of the standard. However, in the case of the subsidiary methods, although the modified drying method has been retained under the title of the high temperature method, the siphon-can and buoyancy methods have been omitted as they are rarely used. In their place methods based respectively on the use of a microwave oven and on the reaction of water in the aggregate with calcium carbide have been introduced. These tests are of more limited application than the oven-drying method but are easier to carry out and provide rapid results. This British Standard also describes the calcium carbide method in appendix A.