Concrete mixer trucks are specialized vehicles; not every driver qualified to operate standard vehicles is qualified to operate a mixer truck. Improper operation can lead to rollovers, excessive wear on hydraulic pumps, motors, and gear reducers, or even severe consequences.
(1) Before starting the mixer truck, ensure the mixing drum control lever is in the “Stop” position.
(2) After starting the engine, allow the mixing drum to rotate at low speed for approximately 10 minutes to raise the hydraulic oil temperature above 20°C before commencing work.
(3) When the truck is parked outdoors, reverse the mixing drum before loading to discharge accumulated water and debris, thereby ensuring concrete quality.
(4) During concrete transport, ensure the discharge chute is securely stowed to prevent swinging caused by looseness, which could injure pedestrians or interfere with other vehicles while driving.
(5) When transporting mixed concrete, the drum rotation speed should be 2–10 rpm. On flat roads, maintain a speed of 2–3 rpm. When driving on slopes with a significant lateral tilt or on roads causing excessive swaying, stop the drum rotation and resume it only after road conditions improve.
(6) Transport time must not exceed the limits set by the batching plant. Do not allow the drum to remain stationary for extended periods during transport to prevent concrete segregation. Drivers should monitor the concrete’s condition and promptly report any abnormalities to the dispatch office for instructions.
(7) When loaded with concrete, the truck must not remain idle at the job site for more than one hour; if this limit is exceeded, the driver must immediately request the site supervisor to take appropriate action.
(8) The concrete slump must not be lower than 8 cm. The time from loading to discharge must not exceed 2 hours in high temperatures, or 2.5 hours in cool, overcast, or rainy weather.
(9) Before discharging concrete, rotate the drum at 10–12 rpm for one minute.
(10) After discharging the concrete, immediately use the onboard hose to wash down the feed opening, discharge hopper, and discharge chute, removing any adhered debris or residual concrete from the vehicle body. Then, add 150–200 liters of clean water into the mixing drum; allow the drum to rotate slowly during the return trip to clean the inner walls and prevent residue from sticking to the drum walls or mixing blades. Drain this water before the next loading operation.
(11) When transporting concrete, maintain the engine speed between 1,000 and 1,400 rpm to ensure maximum torque. To ensure driving safety, the vehicle speed must not exceed 40 km/h during transport.
(12) After operations are complete, thoroughly clean the interior of the mixing drum and the vehicle body; do not leave any residual concrete inside the drum.
(13) Do not run the water pump while it is empty (dry running), and limit continuous operation to no more than 15 minutes.
(14) Keep the water tank full at all times for emergency use. In winter, after shutting down, drain all water from the tank, pump, pipes, and mixing drum. Park the vehicle in a sunny, well-drained location to prevent freeze damage to the machinery.
(15) In winter, install thermal insulation covers and use antifreeze to protect the vehicle. Adjust the fuel grade according to weather conditions to ensure proper machine operation.
(16) When inspecting or repairing the hydraulic transmission system, ensure that the engine and hydraulic pump are depressurized before proceeding.
