Concrete is a major consideration for most construction projects and with 9 main types of concrete available, finding the type that is right for your job is an important first step. At Al Manaratain, we have a number of concrete products available, including precast concrete, concrete blocks, and concrete pavers, as well as ready mix. We’ve already covered the advantages & disadvantages of precast concrete in Bahrain, but today we’re looking at the different types of ready mix concrete and their advantages.
What Is Ready Mix Concrete?
Ready-mix concrete, or RMC, is concrete that has been manufactured in a batch plant according to specific mix designs. RMC is generally delivered in one of two ways:
- Barrel truck or in-transit mixers – If you opt for your RMC to be delivered in this way, it will generally arrive in a plastic state to your construction site.
- Volumetric concrete mixers – This option will have the RMC delivered to you in a dry site, and allows you to mix the concrete on site.
Ready-mix concrete is known for its durability and sustainability, but when manufactured by an expert supplier such as Al Manaratain, the result can be both high quality and more precise.
What Are The Types Of Ready Mix Concrete?
Ready mix concrete comes in three types, with each type is determined by the specific mixture of ingredients.
- Shrink Mixed Concrete
- Transit Mixed Concrete
- Central Mixed Concrete
Shrink Mixed Concrete
Shrink mixed concrete is RMC that has been partially mixed in the original plant mixer. The remainder of the RMC is mixed in the mountain drum of the truck during transit. How much of the RMC is mixed in transit comes down to how much of it was already mixed pre-transit. It is best practice for tests to be carried out in order to determine the amount of mixing required in the mountain drum mixer.
Transit Mixed Concrete
Transit mixed concrete is also called dry-batched concrete. In this type of RMC, all of the basic ingredients (including water) are combined in the truck mixer. During the initial loading of the ingredients, the truck’s mixer drum rotates quickly at charging speed. Ths mixer drum will then slow rotation to a normal agitating speed. Transit mixed concrete comes in three variations:
- Mixed at Job Site – During transit, this type of RMC is revolved in the drum at a slow speed of approximately 2 rotations per minute (rpm). Upon arrival to the construction site, prior to the mix being removed from the truck, it will get 70 – 100 revolutions at a maximum speed of 12-15 rpm. This helps to ensure a smooth mixture.
- Mixed in Transit – The clue for this type of concrete is in the name. The mix is kept at a continual rotation during transit of approximately 8 rpm for roughly 70 revolutions. Once 70 revolutions have been achieved, the rotation is slowed to an agitating speed of 2 rpm until the concrete is finally discharged at the site.
- Mixed in the Yard – RMC mixed in the yard is slowly agitated during the period of transit. Once on the yard, the mixing drum will be rotated at a higher speed of 12 – 15 rpm for approximately 50 revolutions.
Central Mixed Concrete
Central mixed concrete is also known as central batching plant concrete. This type of RMC is mixed thoroughly prior to being loaded into a truck mixer. During transit, the truck’s mixing drum functions as an agitator.
What Are The Advantages of Ready Mixed Concrete?
Ready-mix concrete is a good choice of concrete for construction sites due to the specificity required in mixing it. Due to the nature of RMC being manufactured in specific mixing plants, RMC is known for its consistency and durability. These plants will generally use consistent methods, sophisticated equipment, and exert strict controls over the testing of materials and processes. Other advantages to RMC include:
- Efficiency. The consistent production of RMC in mixing plants allows for mechanised operations. This allows for a higher output of concrete.
- Lowered Consumption. The proper mixing practices and more appropriate handling of RMC helps to lower the consumption of cement by up to 10 – 12%.
- More Environmentally Friendly. The efficiency of producing RMC means that less energy is required in its production. This helps to lower the overall energy required for the production of RMC, making it a more environmentally friendly concrete choice.
- No Need To Store Raw Materials On-Site. As RMC is delivered to your site ready to go, there’s no need to store additional raw materials on site.
- Less Chance of Errors. The automated manufacturing process of RMC requires less human involvement, thereby lowering the potential for human error.
There are a number of advantages to choosing ready mix concrete for your construction job. Its long life span makes it an environmentally friendly and cost-efficient choice for your concrete needs. At Al Manaratain, we’d be happy to discuss your specific construction requirements, and help advise on the ready mix concrete that is most suitable for you.