Minimizing water and cement requirements in Concrete
Goals of Determining the proper mix
To determine the most economical and practical combination of readily available materials.
To produce a concrete that will meet requirements under specific conditions of use.
The majority of concrete used for agricultural applications is supplied by ready-mix producers.
With an understanding of these goals, the customer can communicate better with the ready-mix supplier, and obtain concrete that is suited to the project at hand.
A properly proportioned concrete mix will provide:
- Workability of freshly mixed concrete.
- Durability, strength, and uniform appearance of hardened concrete.
Workability is the property that determines the ease with which freshly mixed concrete can be placed and finished without segregation. Workability is difficult to measure but redi-mix companies usually have experience in determining the proper mix. Therefore, it is important to accurately describe what the concrete is to be used for, and how it will be placed.
If acceptable materials are used, the properties of concrete, such as durability, freeze/thaw resistance, wear resistance, and strength depend on the cement mixture. A mixture with a sufficiently low ratio of water to cement plus entrained air, if specified, is the most desirable.
These properties–and thus the desired concrete quality–can only be fully achieved through proper placement and finishing, followed by prompt and effective curing.
- Proportioning should minimize the amount of cement required without sacrificing quality.
- Quality depends on the amount of cement and the water-cement ratio.
- Hold the water content to a minimum to reduce the cement requirement.
Minimizing water and cement requirements
- the stiffest practical mixture
- the largest practical maximum size of aggregate
- the optimum ratio of fine-to-coarse aggregates
- The lower limit of cement required is specified as a minimum cement content in bags per cubic yard.
- A bag of cement weighs 94 lbs. Typical concrete mixtures include between 5 and 6.5 bags per cubic yard of concrete.
- A minimum cement content assures desirable concrete properties, such as workability, durability, and finishability.
- A minimum amount of cement is required in order to adequately coat all aggregate particles and provide proper bonding.