Ready-mix concrete is a ready-to-use substance that is a mixture of sand, cement, water, and aggregate. Ready-mix concrete is a type of concrete mixed in a batching plant according to the specifications of the customers and delivered to the site by the use of transit mixer as long as it is away from the construction site. Ready-mix concrete (RMC) is concrete manufactured in batch plants.
Ready-mixed concrete is used in construction projects in case the construction sites are nor willing or sometimes are not able to mix concrete on site. For up to medium projects, the cost and time of hiring mixing equipment and labor, also storage for the ingredients of concrete, added to environmental concerns, may not be worth it when compared to the linear cost model of ready-mixed concrete.
Types Of Ready-Mixed Concrete
There are three types of ready-mix concrete, which are based on the mixing of the various components:
Transit mixed concrete
Shrink mixed concrete
Central mixed concrete
Transit Mixed Concrete
Transit mixed concrete is also called dry-batched concrete, for all the basic components, including water, are charged directly into the truck mixer. This mixed drum is revolved quickly at charging speed during the loading of the substances afterward it keeps on rotating at a normal shaking speed. The Transit mixed concrete is divided into three various types in turn:
Concrete mixed at the construction site
During transportation to the destination, the drum is being revolved at a slow speed, but after reaching the construction site it is starting to revolve at maximum speed.
Concrete mixed in transit
In this case, the drum speed is medium during the transit time, and after it is slowed down to agitating speed till discharging the concrete.
Concrete mixed in the yard
The drum is being revolved at high-speed for approximately 50 revolutions in the yard itself, then, during the transit time, it turns the slow agitating speed.
Shrink Mixed Concrete
The concrete is mixed in the plant mixer only in part and then during the transit time balance mixing is done in the truck-mounted drum mixer. The amount of mixing in a transit mixer is based on the extent of mixing done in the central mixing plant.
Central-mixed concrete is also known as the central batching plant where the concrete is fully mixed before loading into the truck mixer. Usually, the plants are also referred to as pre-mix or wet-batch plants. During the transit time, the truck mixer acts as an agitator. Although, sometimes when workability demand is not high or the lead is less, dump trucks or non-agitating units can also be used.
Ready-mixed concrete delivery can be implemented by transportation or placing at a construction site using various methods. The simplest and the most common method is the chute fitted to the back of transit mixer trucks, that is suitable for placing concrete near the locations where a truck can simply reverse in.
Crane hoppers, dumper trucks, truck-mounted conveyors, or wheelbarrows are used to place concrete from a truck where access is not direct. Several types of concrete mixes can be suitable for pumping with a concrete pump.
A concrete pump is a machine that is used for transferring liquid concrete by plumping. There are two types of concrete pumps:
Boom concrete pump
Line concrete pump
The first type is called “boom”, for it uses a remote-controlled arm (with the same name) which is used for placing concrete accurately. These types of concrete pumps are also used mostly for larger construction projects as long as they can pump at very high volumes.
The second type is mounted on a truck or placed on a trailer. These line concrete pumps require flexible or steel concrete placing hoses to be manually attached to the outlet of the machine. The hoses are linked to each other and lead to wherever the concrete need to be placed.
A concrete plant or batch plant (also known as batching plant or a concrete batching plant) is equipment that includes different ingredients to form concrete. As long as there are several types of that equipment, some of them can include air, water, sand, admixtures, aggregates, slag, cement, as well as fly ash and silica fume.
Concrete plants can have a variety of accessories and parts, such as mixers, aggregate bins, cement bins, heaters, cement silos, heaters, batch plant controls, and dust collectors. The main component of the concrete plant is the mixer. There are various types of mixers:
The concrete plant uses a control system to control the work of the machine. These types of equipment employ a computer-aided system to assist in the accurate and quick measurement of input constituents or components.
Types Of Concrete Plants
There are many formed types of concrete plants. A concrete plant can be divided into wet mixing plants and dry mix plants depending on the usage of a central mixer. There can also be mobile concrete plants and stationary concrete plants depending on are they movable or no.
Traditionally, all ready-mix producers aim to find the best proportions of ingredients instead of optimizing their concrete mixes and give them strength, workability, durability, and other required properties. This is, of course, not easy, as any subtraction or addition entails adjustments to the other ingredients.
Cement Mix design or Concrete Mix Design
Cement mix design is quite often referred to as the concrete mix design. Yet, cement is just one an ingredient of concrete. Cement mix is a binding material, which allows concrete to set harden and stick to other substances. For this reason, cement can not and should not be used instead of concrete mix design.
Concrete mix design is the process of selecting the ingredients for concrete mixtures and deciding on their proportions. During the process of designing a concrete mix, there is always a need to consider the desired durability, strength and workability of the concrete for the project.
What Is Cement Itself?
A cement is a binder (or binding agent, that is any substance or material, holding or drawing other materials together to form a cohesive whole chemically or mechanically) substance that is used for construction for setting, hardening and adhering to other materials bind them together.
Cement, which is used in constructions, in general, are inorganic, lime and calcium silicate-based, they can as well be characterized as either hydraulic or non-hydraulic.
Hydraulic cement sets and becomes adhesive because of a chemical reaction between the water and dry ingredients. This allows setting in wet conditions or underwater.
non-hydraulic cement does not set in wet conditions as the previous one does, instead, it sets as it dries and reacts with carbon dioxide in the air.
Concrete Mix Calculations
Concrete mix calculations are the actions to calculate the quantities of materials for concrete (cement), aggregates and sand.
Quantities of materials for concrete such as cement, sand, and aggregates for production of required quantity of concrete of given mix proportions such as 1:2:4 (M15), 1:1.5: 3 (M20), 1:1:2 (M25) can be calculated by absolute volume method.
The method is based on the principle that the volume of a complete compacted concrete is equal to the absolute volume of all substances of concrete.
Quantities Of Materials for per cubic meter
Consider concrete with a mix proportion of 1:1.5:3 where, 1 is part of cement, 1.5 is part of fine aggregates and 3 is part of coarse aggregates of a maximum size of 20mm. The water-cement ratio required for the mixing of concrete is taken as 0.45.
Ready-Mix Concrete Suppliers
Concrete is a substance capable of doing many things, and it has been used for centuries in a wide range of construction projects. Ready-mix concrete suppliers help build foundations, roadways, dams, driveways, bridges and so on. Ready-mix concrete companies can also help cast into different colors and shapes providing unmatched durability in terms of compressive strength and resistance to extremes of the weather.
As it is already said, concrete forms the very foundation, walls, and floors of most of the modern buildings both residential and commercial. Concrete delivers a number of benefits. Self-compacting concrete makes the building stronger and more durable. While it also reduces energy use through its ability to decrease the fluctuations of the temperature in buildings over the course of the day. Another benefit is a natural noise barrier provided by concrete.