What is Ready-Mixed Concrete?

Definition from DIN 1045 "Concrete and reinforced concrete“ (1988 issue)

Ready-mixed concrete is concrete whose components are admixed off site and delivered by vehicles to the site in a ready-to-place condition.

Functionality

A ready-mixed concrete plant contains silos for binders (cement and fly ash). Aggregate is stored either in open boxes (star arrangement) or silos (tower arrangement). Water is taken from either the recycling plant or the mains. For additives, closed containers are provided.

The control of the RMC plant is normally computer-supported. According to the standard, weighing of the raw materials must meet an accuracy of +/- 3 %. This is achieved by using appropriate scales for all raw materials and tare and operating them by means of PC control.

All residual concrete quantities returning to the RMC plant must be recycled in accordance with the valid recycling regulations (German Kreislaufwirtschaftsgesetz). This is why the majority of German RMC plants are equipped with recycling systems. In this process, the returning concrete trucks must be flushed with water at the RMC plant with the residuals being separated into water with fine particles and coarse aggregate.