All PCC intended for pavement use is ready-mixed concrete. Ready-mixed concrete refers to PCC that is delivered to the customer in a freshly mixed and unhardened state (NRMCA, 2002). Therefore, PCC production involves the batching and mixing of portland cement, aggregate, water and admixtures to form a ready-mixed concrete in accordance with the approved mix design. There are three basic production methods: truck mixing, central mixing and shrink mixing. Other methods of PCC mixing do exist but they are not common in pavement applications and are therefore not covered in Pavement Interactive. Truck mixed PCC is dry batched into a concrete mixing truck then blended in the truck either at the batching plant or in route to the job site. Central mixed PCC is batched and mixed in a central facility and then loaded into a truck for transport to the job site. Shrink mixed PCC is partially mixed in a plant mixer and then discharged into a truck mixer where the mixing is completed. More detailed information on plant operations can be found in:
- American Concrete Pavement Association. (1995). Construction of Portland Cement Concrete Pavements. National Highway Institute Course No. 13133. AASHTO/FHWA/Industry joint training. Federal Highway Administration, Department of Transportation. Washington, D.C.
- National Ready Mixed Concrete Association (NRMCA). (2002). NRMCA web site, Concrete Basics home page. National Ready Mixed Concrete Association. Silver Spring, MD. http://www.nrmca.org.