Basic Process of Concrete Mixing Operations

Basic Process of Concrete Mixing Operations

Concrete mixing is a process that transforms raw materials such as cement, sand, aggregate, and water into a uniform, usable concrete through systematic operations. Following a clear and safe basic process is crucial for ensuring concrete quality, improving operational efficiency, and guaranteeing personnel safety. The entire process can be logically divided into three stages: preparation, mixing, and finishing.

Stage One: Preparation and Inspection Before Operation. This is the foundation of safety and quality. First, a flat, solid site must be selected for placing the mixer, ensuring it is stable and does not shake. Before starting the machine, a thorough inspection must be performed: check if the mixing blades are securely installed and not loose; check if lubrication points need oiling; and confirm that the discharge mechanism operates smoothly. At the same time, according to the predetermined mix ratio (for example, how many buckets of sand and aggregate per bag of cement), the dry aggregates and cement should be pre-measured and prepared near the equipment, and sufficient clean water should be prepared. All operators must wear safety helmets, dust masks, safety glasses, and non-slip work shoes.

Stage Two: Feeding, Mixing, and Discharging. This is the core of the process, and the key is controlling the feeding sequence and mixing time. Start the mixer and let it run empty for a short time to confirm normal operation before starting to feed the materials. It is recommended to use the "wet first, then dry" or "pre-mixed mortar method" to improve the mixing effect: first add most of the mixing water to the mixing drum, then add all the sand and cement, mix for about 1 minute to form cement mortar, and finally add the aggregate and the remaining water, continuing to mix. The total mixing time, starting from the completion of adding all materials, generally needs 2 to 3 minutes, until the mixture is uniformly colored and there are no dry lumps or cement clumps. During the mixing process, it is strictly forbidden to put hands, tools, or any objects into the rotating mixing drum. After mixing is complete, place a wheelbarrow or hopper under the discharge port and operate smoothly to discharge the concrete.

Stage Three: Cleaning and Equipment Maintenance After Operation. After discharging, the concrete should be used as soon as possible to avoid hardening due to prolonged storage in the equipment or transport vehicles. Immediately afterward, thorough cleaning is essential: add an appropriate amount of water and a few handfuls of small stones to the mixing drum, and run the machine empty for 3 to 5 minutes.  The rotation and friction will dislodge any remaining material adhering to the drum walls and blades. Then, drain the dirty water. This process usually needs to be repeated once or twice. Afterward, thoroughly rinse the inside and outside of the mixing drum, the discharge chute, and the equipment surface with a high-pressure water gun or hose. Finally, clean the work area and return all tools to their proper places. A good cleanup not only significantly extends the equipment's lifespan but also provides safe and convenient conditions for the next operation.