Wednesday, February 08, 2017

Batching

Batching


In batching concrete, the quantity of both cement and aggregates shall be determined by mass, admixture, if solid, by mass, liquid admixtures may however be measured in volume or mass, water shall be weighed or measured by volume in a calibrated tank. Batching materials by weight is preferable and the BIS emphasis its use.
  • Weight batching:

Cement comes in 50 kg bags. The aggregate and sand can be weighed by a variety of weighing devices, the simplest being a spring dial scale, to more accurate portable batchers.


  • Volume batching

IS 456 allows batching by volume, only where weigh batching is not practical. When volume batching is practiced, use of measuring boxes, control on water- cement ratio, measuring bulking of sand and accounting for surface water of aggregates need to be strictly adhered to. To ensure certain degree of consistency, frames (wooden/steel batch boxes) should be used.