Batching is the process of measuring and introducing into the mixer the ingredients for a batch of concrete, which is often called as concrete batching systems. Most specifications require that batching of concrete ingredients be carried out by mass rather than by volume. This is because bulking of damp sand causes inaccuracies in measurement. Water and liquid admixtures can be batched accurately either by volume or weight. In many countries, most concrete today is batched and mixed by ready-mixed concrete plants, where the batching is generally automatic or semiautomatic rather than manual.
Improper handling and mixing of fresh concrete mixtures that are not uniform in appearance is attribute to inadequate mixing. Therefore, accurately proportioned concrete ingredients must be mixed thoroughly into a homogeneous mass. Depending on the cost economy, type of construction, and amount of required concrete, the mixing operation can be performed on site or in a central off-site facility(ready mixed concrete plant). On-site concrete mixers can be either stationary or paving type.
Transportation of the ready-mixed concrete to a job site should be done as quickly as possible to minimize stiffening to the point that, after the placement, full consolidation and proper finishing become difficult. The causes and control of stiffening or loss of consistency, which is also referred to as slump loss. Under normal conditions there is usually a negligible loss of consistency during the first 30 min after the beginning of cement hydration. A quick transportation also saves money and costs, right?