Types of ready mix concrete
Ready-mix concrete (RMC) is defined as custom-made concrete that has been manufactured in a factory or manufactured within a batch plant specifically based on mix designs. RMC is a precise mixture well-known for offering durability and sustainability and is generally delivered in one of two ways:
Volumetric concrete mixers: Here ready-mix concrete will be delivered to the worksite where you could mix the concrete on site.
Barrel truck or in-transit mixer: Here the prepared concrete is delivered to the work site in a transit mixer that is installed over a truck. This type of ready-mix concrete is recommended as it is sure to guarantee higher durability.
Types of Ready-mix Concrete:
Depending upon the specific mixing of the various ingredients and cements there are three types of ready mix concrete or RMC as mentioned below.
Central mixed concrete
Shrink mixed concrete
Transit mixed concrete
Central mixed concrete. This is also called central batching plant concrete. Central mixed concrete is so called because it is formed when concrete is mixed thoroughly before being loaded into a truck mixer. While the transportation of the concrete takes place, the truck drum mixer only acts as an agitator. The concrete plant at times is also referred to as a wet-batch or premix plant. When there is a low workability requirement or when the lead is less, dump trucks or non-agitating units could also be employed.
Shrink mixed concrete
Shrink mixed concrete is formed when the concrete is partially mixed in the concrete batching plant mixer, while the remaining is mixed in the truck-mounted drum mixer during transit time. The amount of mixing in the transit mixer is based on the extent of mixing done in the central mixing plant. To establish the requirement of mixing in the drum mixer the best practice would be to conduct a test.
Transit mixed concrete
It is also called dry-batched concrete. In the case of transit mixed concrete, it is made when all the basic ingredients including water are charged directly into the truck mixer. Initially, while loading the construction materials, the truck’s mixer drum revolves very fast at charging speed, after which it rotates slowly and continues to rotate until it reaches a normal agitating speed.
Transit mixed concrete RMC comes in three different types of variations namely.
Concrete mixed at the job site
While it is being transported to the construction site, the drum revolves at a slow speed or an agitating speed of 2 revolutions per minute (RPM), but on reaching the destination site just before the discharge of the construction materials takes place, it will get almost around 70 to 100 revolutions and revolves at a maximum speed of about 12 rpm to 15 rpm. This happens to ensure homogeneous mixing so that a smooth mixture is formed.
Concrete mixed in transit
In concrete mixed in transit, the mixer drum speed is kept medium and constant during the transit time. It revolves continually for roughly 8 rpm at 70 revolutions.
After 70 revolutions, the rotation is slowed down to an agitating speed of 2 rpm till discharging the concrete takes place at the site.
Concrete mixed in the yard
In concrete mixed in the yard, the mixer drum is at an agitating speed of 2 rpm during the period of transit. On reaching the site, it is turned at a high speed of 12 rpm to 15 rpm for approximately 50 revolutions when in the yard.
SD Conmix continuously strives to deliver high quality ready concrete mix as per customer expectations. Ready-mix concrete and construction materials from SD Conmix can be used for various construction purposes. We aim to provide perfect concrete solutions of high quality and strength for many years to come.
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