By far the greatest amount of concrete produced in the U. S. is 
known as ready-mixed concrete. The term ready-mixed concrete means 
any portland cement concrete mixture which is ready to use on arrival 
at the job site. Ready-mixed concrete includes: (1) transit-mixing, 
or concrete produced from a central-batching plant, where the materials 
are proportioned and placed in truck-mixers for mixing enroute to the 
job or after arrival there, and (2) central-mixing, or concrete pro- 
portioned and mixed at a central-mixing plant and hauled in agitator- 
type trucks to the job. 
The major items, or classes, or equipment required in setting up 
a ready mixed concrete plant may be enumerated as follows: 
1. Means for delivering, unloading, storing, and handling 
fine and coarse aggregates. 
(a) Delivering - Railroad gondola cars (and railroad 
accessories) and/or dump trucks. 
(b) Storing - Open field stockpiling, elevated closed 
bins. 
(c) Handling - Pit dumps equipped with conveyor belts 
(or bucket belt system) to move material either to stockpiles or to 
elevated bin storage. If aggregate has to be classified into specific 
particle sizes, washing and screening plants are also required. 
2. Provision for delivering, unloading, storing and handling 
cement: (a) in sacks, (b) in bulk. 
(a) Delivering - Sacked cement should be delivered in 
closed railroad cars or closed trucks to avoid effects of adverse 
weather. Open vehicles may be used for short hauls in dry weather. 
Bulk cement requires delivery by special bulk delivery railroad cars 
or trucks were the cement is completely enclosed from the weather. 
(b) Unloading - Sacked cement requires forklifts for 
unloading palletized sacks. Bulk delivery requires unloading cement 
into elevated bins by pneumatic pumps. 
(c) Storing - Bulk cement is stored in elevated closed 
weather-tight bins, sacked cement is stored inside weather-tight ware- 
houses. 
3. Equipment for elevating the aggregates and cement. Either 
aggregate or cement can be transported on conveyor belts if the slope is 
not too steep. For steep slopes bucket conveyors are used. 
4. Overhead compartment bins for storage of various sizes 
of fine and coarse aggregates; also for one or more types or brands of 
cement when bulk cement is used. 
5. Weighing batchers for measuring the quantities of aggregate, 
cement, and water. Batching systems range from completely manual 
