Standard test method for water content of sand and gravel
Weigh 500g of sand and gravel, dry it in an oven or other tools, and weigh it.
According to the industry standard of the People’s Republic of China JGJ52-2006
Moisture content of sand %=(weight before drying-weight after drying)/weight after drying*%100. Accurate to 0.1%
Why sand and gravel moisture content should be tested regularly
The amount of sand and gravel in ready-mixed concrete is about 800-1100kg/m², and every 1% of its water content will bring about 8-11kg of water consumption in concrete.
In particular, sand is usually collected from rivers, and its moisture content varies greatly. If the moisture content is not checked frequently, and the water consumption for mixing is adjusted in time, it will cause great fluctuations in the slump, pumpability and strength of concrete in each tray.
Control of Moisture Content of Machine-made Sand
Concrete artificial aggregate is generally produced by wet method, that is, during the production process of machine-made sand, a large amount of water is used to wash the aggregate. The finished sand just produced has a moisture content of about 12% to 15%, and excess free water needs to be removed. The new specification greatly increases the content of stone powder and fine particles, resulting in a huge change in the difficulty of dehydration of fine aggregates.