Step 1: Raw Material Supply and Storage
Ready-mix concrete consists of four primary components:
1. Aggregates
Aggregates make up approximately 60–75% of the concrete volume and include sand, gravel, or crushed stone sourced from quarries or riverbeds.
2. Cement
The most commonly used type is Ordinary Portland Cement (OPC), which acts as the binding material.
3. Water
Water initiates the hydration reaction with cement, enabling strength development.
4. Admixtures
Chemical additives (liquid or powder) used to enhance concrete properties such as workability, setting time control, durability, and reduced permeability.
At the batching plant, each material is stored separately in dedicated silos, bins, or tanks to maintain quality and prevent contamination.
Step 2: Precise Batching (Weighing)
One of the most critical stages in producing high-quality concrete is accurate batching according to the Mix Design.
In modern batching plants, this process is fully automated:
Aggregates are weighed using calibrated scales or batching bins.
Cement is transferred from silos via screw conveyors and weighed precisely.
Water and admixtures are measured using flow meters or load cells.
This precision ensures uniformity in every batch and eliminates human error.
Step 3: Concrete Mixing
After batching, materials enter the mixing phase. Mixing time is calculated from the moment water is added and the mixer begins operating. The goal is to produce a homogeneous concrete mass.
There are three main mixing methods:
1. Central Mixed Concrete
All materials are fully mixed in a stationary mixer at the plant. The finished concrete is then discharged into the truck mixer, which acts only as an agitator.
The drum rotates slowly (2–6 rpm) during transportation to prevent segregation.
This method provides maximum quality control and is ideal for large or critical projects.
2. Transit Mixed Concrete (Truck Mixed)
Dry materials are loaded into the truck mixer at the plant, and mixing occurs during transportation.
The drum rotates at a higher speed (4–16 rpm) to complete the mixing process.
This method is typically suitable for short distances between the plant and project site.
3. Shrink Mixed Concrete
A hybrid method where materials are partially mixed at the plant (about 30 seconds) before being transferred to the truck mixer.
Final mixing is completed during transit at 4–16 rpm.
This approach balances plant quality control with transportation flexibility.
Step 4: Loading and Transportation
Once the concrete is ready, it is discharged into the truck mixer drum. From this moment, time becomes a critical factor.
According to ASTM International (ASTM C94 standard):
Concrete must be discharged within 90 minutes from the start of mixing.
The drum should not exceed 300 total revolutions.
Excessive rotation may cause segregation and quality loss.
Modern fleets often use GPS systems to optimize delivery timing and ensure on-time arrival at the construction site.
Step 5: Quality Control
Upon arrival at the project site, quality control tests are performed before discharge, including:
Slump test (to measure workability)
Temperature check
Sampling for compressive strength testing
Reputable ready-mix plants operate under international standards such as EN 206 to ensure consistent quality.
Conclusion
Ready-mix concrete production is a highly engineered and multi-stage process. From raw material selection and precise batching to controlled mixing, timely transportation, and strict quality control, each step ensures strength, durability, and uniformity.
Proper execution of these stages guarantees reliable concrete performance in modern construction projects.
Ready-Mix Concrete Production: Step-by-Step Process
