Making concrete yourself takes organization, time, and energy. Plus, if you need concrete for big construction projects, it’s almost unthinkable to think of doing it all yourself. This is where concrete batching plants come in.
A concrete batch plant works by storing the various constituent elements of concrete (water, cement, aggregates, and additives) in suitable tanks and then manufacturing custom concrete at the request of each customer.
Indeed, a concrete batch plant is an installation designed to produce concrete in large quantities. It can be installed either on a specific site, near a quarry, or permanently on urban areas’ outskirts. Let’s dive in and learn detailed information about:
- What is a concrete batching plant
- The step-by-step operation process
- The different types of concrete plants
- The pros and cons of ready-mixed concrete
What Is a Concrete Batch Plant?
A concrete batch plant is a factory that stores the various constituent elements of concrete – water, cement, aggregates, and additives – in suitable tanks. Then, it manufactures the custom-made concrete at the request of each customer. The concrete manufactured in the plant is produced in large quantities. It is of high quality since the plant must comply with the regulations in force.
The plants are equipped with automatic machines that allow the continuous production of concrete. This is possible because of previously entered formulas. Then, it automatically makes corrections to the quantities of water according to the aggregates’ water content. Automation limits, to some extent, the exposure of personnel to cement dust and silica dust, both sources of health problems.
Note: Don’t confuse a concrete batching plant with a concrete mixer!
The first one is a fixed production unit. The second one allows for manual manufacturing of concrete in small quantities, directly on the site.
However, depending on the case, mobile concrete plants can also be installed on large-scale construction sites. These make it possible to produce concrete directly according to the progress of the pour. This type of mobile unit requires ample space for its installation and a constant supply of water. As a general rule, its production rate is 35 m³ of concrete/hour. In practice, the mobile concrete batching plant is used in rare circumstances for professional sites.
What Are the Components of a Concrete Batching Plant?
A traditional concrete batching plant mainly consists of:
- Cement silo. Equipped with a filter to ensure the best possible quality
- Aggregate silo. Sand and gravel are transported by truck, train, or boat from the quarries. On arrival, they pass through a hopper before being transported via conveyor belt to this storage silo.
- Dosing tank
- Adjuvant tanks. Each contains a different adjuvant: setting accelerator, retarder, and plasticizer.
- Weighing system
- Water supply equipment. Consist of a tank and a pump for the transfer of liquids.
- Concrete mixer
Each concrete batching plant component has safety systems preventing any leakage or pollution, whether terrestrial or atmospheric. The cement silo has a dust filter to prevent release into the atmosphere. As for the adjuvant tanks, they are raised and installed themselves in sealed compartments and certified frost-free.
The aggregates (sand, gravel, etc.) are first transported to the dosing tank using a silo or a skip (feed bucket mounted on a lifting and tilting system). Then they are weighed by a weighing belt and transported by the conveyor belt to the mixer (or the concrete mixer).
The mixture’s various elements are then introduced into the mixer: cement, water, and any additives. The quantities of material and the mixing times depend on the type of concrete produced and its constituents’ characteristics. Once the operation is complete, the mixture is loaded into a mixer truck or transported by concrete mat to the site.
In general, the control unit is operated from a control cabinet, mainly allowing:
- the control of material weighing systems
- measuring the humidity of the aggregates using hygrometry detectors
- the water supply dosage according to the desired level of fluidity
Note: Some models incorporate a vertical aggregate silo, with the advantage of reducing the plant’s size and the sound volume produced by the flow of materials.
Also, more and more mixers are equipped with sealed covers which prevent dust from escaping during mixing. This has the double advantage of improving the quality of the concrete produced and better protecting the environment.
Why Use a Concrete Batch Plant?
There are many advantages to using a concrete plant.
First of all, it allows you to save considerable time on completing your site: no need to carry out your concrete yourself! The concrete produced in the plant is quality certified (dosage, storage of elements in suitable dry places, additives in precise quantities, etc.). Therefore, it is the assurance of solid slabs that do not sag or crack over time, unlike the risks presented by those from handcrafted manufacture.
Also, the concrete batching plant allows you to transport a large quantity of concrete to the site. For small volumes, delivery by a concrete mixer from 1 m³ is entirely possible. An additional price may nevertheless be requested due to the displacement of the almost empty router. This one can generally contain 7 to 8 m³ of concrete.
Using a concrete batching plant, you, therefore, ensure unparalleled durability of your concrete structure while saving time on its completion.
The concrete batching plant has automated operations. A control cabinet allows the following steps to be carried out:
- Weighing control
- Transport of materials
- Measurement of the humidity of the concrete
- Level of fluidity
For each type of concrete, a formula is pre-established, and a program is associated. The professional, therefore, only needs to launch the program corresponding to the customer’s order: type of concrete chosen and quantity.
Very concretely, here are the various stages of concrete preparation in a plant:
Preparation and Transport of Aggregates
The aggregates are the first to be added to the mixer. They are therefore transported via a skip from their silo to a dosing tank.
At this point, the aggregates can also be sieved to retain only the finest. And yes: the grain size can be more or less important depending on the concrete. Some sites require fine gravel concrete for a more natural aesthetic appearance.
Once weighed and sieved, the aggregates are placed directly in the mixer or a waiting hopper.
Transfer of the Other Constituent Elements of the Concrete
The other elements of the mixture are transported from their tanks to waiting hoppers (using belts or pumps) or else poured directly into the mixer after the aggregates, in the following order: cement, water, then additives.
Thanks to the predefined programs, each component arrives in precise quantities. Mixing water comes from water treatment reserves, rivers, or lakes. Like the other components of concrete, it is conveyed in extremely precise amounts. Concrete with too much water will lose its mechanical resistance.
Mixing the Concrete Constituents
The mixing of the concrete is done for a determined time, depending on the nature of the latter. Also, the mixing time depends on the amount of material to be produced. Depending on the volume of the mixer, this time is more or less important. The average production rate is estimated at 60 m3/h for a 1000 l mixer.
Note: During the mixing process, no dust comes out thanks to the presence of sealed covers.
Loading Concrete for Transport
Once the concrete is manufactured, it’s poured into a concrete mixer, a mixer pump, or even a carpet truck -depending on the accessibility characteristics of the site.
Transportation and Delivery of Concrete
You must arrive at the site within the hour: this allows the concrete to maintain consistency and, therefore, optimum resistance. On the way, the concrete mixer kneads the mixture continuously so that it does not harden.
Return of the Concrete to the Plant
When returning to the plant, the so-called “return” concrete (residues present in the router) is eliminated while cleaning the concrete mixer in a plant’s dedicated area. The remaining water and concrete pass through several settling tanks until filtered water is obtained, then recycled.
What Are the Different Types of Concrete Batching Plants?
Concrete batching plants are divided into different types. Plants are generally divided into stationary concrete batching plants and mobile concrete batching plants. This is a basic classification that many manufacturers distinguish at the time of production.
Stationary Concrete Plants
Stationary concrete plants are used to supply concrete to construction sites in large quantities.
This type of plant does not require specific space on the site to store materials, limiting the risk of damage. Also, factory-type stationary concrete plants ensure high-quality concrete production per requirements without the risk of material dosage errors.
Besides, factory-type concrete batching plants carry out various material quality checks throughout the concrete manufacturing process. On the other hand, they involve a delivery time linked to routing by a mixer truck, more accessible access to the site, and rapid implementation.
Mobile Concrete Plants
Concrete can be manufactured in a concrete batching plant temporarily installed on the construction site.
The mobile concrete plant allows concrete production on demand, depending on the progress of the site. This type of plant assumes sufficient space for its installation and raw materials’ storage (cement, sand, water).
Also, raw materials should be stored in a clean, dry place away from moisture. Indeed, materials such as water and additives should not come into contact with water. Mobile concrete plants bring together heavy installations capable of producing up to 35 m³ / hour.
Dry Mix Concrete Plants
The dry concrete batching plant uses digital or manual scales to weigh the various constituents of concrete. Subsequently, they are unloaded in a chute which flows into a truck. During this time, the water is also volumetrically weighed or metered and discharged through the same loading chute in the mixer truck. All the materials are then mixed for at least 70 to 100 turns during transport to the job site.
Wet Mix Concrete Plants
The wet concrete batching plant puts some or all of the dry mix plant materials; they add water into a concrete mixer located at the center. The concrete will be unloaded into a mixer truck or agitator for transport to the construction site after mixing.
In short, the difference between the dry mixing installation and the wet mixing installation is that the wet installation includes a central mixer to produce a more stable mixture. The wet mix plant has deviations from breaks and variations from load to load. With a central mixing installation, all loads have the same actions. There is an initial quality control point when unloading from the central mixer.
Pros and Cons of Ready-Mixed Concrete
Ready-mixed concrete can be made traditionally or industrially. Indeed, it is either manufactured with a concrete mixer or in a concrete batching plant (by following the process described above in this article).
In the latter case, the concrete is delivered to the site using a concrete mixer truck. The two manufacturing methods are complementary.
Let’s see what the pros and cons of ready-mixed concrete delivered by a mixer truck are:
- Guaranteed quality. The plant complies with standards and delivers to professional sites.
- Easy installation. The ready-to-use concrete arrives at your site; what remains to do is pour it into the formwork.
- Production of large volumes. Because of its negotiating power over the purchase of raw material, It manufactures concrete inexpensively!
- Many types of concrete are available. Depending on the additives, the proportion of water, cement, and aggregate, many concrete types can be made, leaving you with a wide choice depending on your site.
- Simplicity. Concrete production in a plant avoids arduous tasks such as loading concrete mixers on construction sites. Truck delivery is also very convenient if the work area is accessible.
- Significant time-saving. Indeed, thanks to the delivery by truck, the pouring is very fast.
- Economic advantage. Ready-mix concrete prevents inventory downtime, avoids waste, and improves your productivity.
- Delivery of concrete can be expensive for small quantities. Obviously, as in any other business, delivery for smaller quantities is always more expensive than larger volumes.
- The truck must be able to access the site. Otherwise, you will be billed for an additional “handling” service.
- Limited lifetime. As you know, fresh concrete obviously cannot be stored. It must be installed quickly; otherwise, it will become unusable.
Transportation of Concrete
In the absence of a concrete mixer or large volumes, it is possible to purchase ready-mixed concrete. A mixer truck is used to transport the concrete from the plant to the site; it maintains, thanks to its tank’s rotation, the consistency of the concrete they transport.
On-site, the concrete transport between the plant (or the mixer truck) and the structure is done using a pump (stationary or on a truck) or a concrete bucket lifted using a crane.
How To Get the Best Price on Concrete
The price of the delivered concrete varies according to several factors:
- The quantity of concrete ordered
- The type of concrete
- The distance between the plant and your site
Note: Delivery by concrete mixer truck has a very significant impact on the price of concrete. Indeed, according to the National Ready Mix Concrete Association (NRMCA), the national average price for concrete delivery is between $100 to $130 per cubic yard.
Which Concrete Supplier To Choose?
The concrete market is fragmented, with large international groups on the one hand and many independent players on the other. Faced with this multitude of actors, it is sometimes difficult to navigate. You have two options:
- Find concrete batch plants located near you. You can then contact them one by one to get a quote. Note: This solution can be time-consuming. Besides, you must have the knowledge and experience to determine the type of concrete desired and anticipate delivery vagaries. The time it takes to obtain the quote can also be longer since some plants prioritize their professional customers’ sites.
- Go through an online delivery platform. Indeed, some internet platforms allow you to order fresh concrete online. They take care of putting together suppliers of ready-mixed concrete to get you the best price regardless of the quantity of concrete ordered. This is a good solution when you request a minimum of 1 m³ of concrete.
However, you should know that concrete plants usually allow you to get the best value for money on the market. Nevertheless, each plant will offer a slightly different price for the same site, depending on the criteria previously stated.
Don’t hesitate to compare quotes and compete for the best price!
In short, concrete batch plants make it possible to produce large quantities of concrete more locally. There are many types of power plants, but they are always characterized by common components:
- A horizontal or vertical mixer
- A weighing device for aggregates and cement
- One or more cement storage silos and any additions
- Storage tanks for adjuvants
- Elements for loading aggregates and cement
In order to get the best price for your concrete, don’t forget to compare the quotes offered by concrete batch plants versus online platforms.