Concrete that is delivered to the customer in a freshly mixed and unhardened state is called ready mixed concrete. The quality and quantity required vary according to the project.

The "ASTM C 94 -- Standard Specification for Ready Mixed Concrete" defines the quality formats:

• Performance -- wherein the client specifies the aggregate size, slump, air content, and strength. In this case, SCP is responsible for the design of the mixture.
• Prescription -- wherein the client specifies the aggregate size, slump, air content, cement content or weight of cement per unit volume of concrete. Here, the purchaser accepts responsibility for concrete strength and performance.

Quantity is by unit of volume, either cubic yards ((yd³) or cubic meters (m³). Allow for wastage, spillage, loss of air, etc. by ordering 5-10% more than estimated requirements.

The processing and disposal of returned concrete can be expensive for us as we must comply with environmental regulations. Towards the end of a large job, reevaluate the additional volume of concrete you need and let us know.

Contact our technical services department for more information.