A concrete whose constituents are weigh-batched at a central batching plant, mixed either at the plant itself or in a truck mixers, and then transported to the construction site and delivered in a condition ready to use is termed as Ready Mix Concrete (RMC).
|Fig.1: RMC Plant|
|Fig.2: RMC Transporting Truck|
The RMC is produced under factory conditions and permits a close control of all the operations of manufacture and transportation of fresh concrete. Due to its durability, low cost and the customization ability for different applications, RMC is one of the most versatile and popular building materials. RMC is ordered and supplied by volume in a freshly mixed and unhardened state.
Proportioning of RMC
The proportioning of an RMC aims at obtaining an economical and practical combination of materials to produce concrete with the properties desired for its intended use, such as the workability, strength, durability and appearance. The points to be considered for the proportioning of RMC are as follows:
- Concrete aggregates are required to meet appropriate specification and in general should be clean, strong and durable
- Fly ash or other supplementary cementitious materials which enhance concrete properties are normally added to RMC
- Admixtures are commonly used in relatively small quantities to improve the properties of fresh and hardened concrete such as the rate of setting and the strength development, especially during cold and the hot weather conditions
Advantages of RMC
The following are the advantages of RMC:
- Reduction in cement composition by 10 - 12% due to better handling and proper mixing. Further reduction is possible if the mineral admixture or the cementitious materials are used
- Since RMC use bulk cement instead of bagged cement dust pollution will be reduced and the cement will be saved
- Conservation of energy and resources because of saving of cement
- Environment pollution is reduced due to less production of cement
- With better durability of structure, their overall service life of increase and there is saving in the life cycle cost
- Quality assurance due to mechanical handling and uniformity of processes
- Eliminating or minimizing human error and reduction in dependency on labor
- General Benefits like speedy work stability of the structures etc.
Disadvantages of RMC
- Generation of additional traffic may affect the mix
- Concrete will limit the span between the mixing plant and the ddestination