A mixer truck, used to transport construction concrete; due to its shape, it is often referred to as a snail truck or olive truck. These trucks are equipped with a cylindrical mixing drum to carry mixed concrete.

During transportation, the mixing drum is kept rotating to prevent the concrete from solidifying. After delivering the concrete, the mixing drum is usually rinsed with water, as residual hardened concrete occupies space, reducing the drum's capacity over time.

 

 

 

Concrete mixer trucks consist of a vehicle chassis and a concrete mixing and transport device. In China, the chassis of domestically produced concrete mixer trucks mostly use Class II universal chassis provided by vehicle manufacturers. The mechanism mainly includes a power take-off, front and rear drum supports, a reducer, a hydraulic system, a mixing drum, control mechanisms, and a cleaning system. The working principle involves extracting power from the vehicle chassis via the power take-off device, driving the variable pump of the hydraulic system to convert mechanical energy into hydraulic energy, which is transmitted to a fixed displacement motor. The motor then drives the reducer, which in turn drives the mixing device to agitate the concrete.

 

 

 

Based on the moisture content of the concrete carried by mixer trucks, they are categorized into wet mix, dry mix, and semi-dry mix transport vehicles. Wet mix concrete mixer trucks are the most commonly used. They can transport concrete produced at mixing plants (or stations) or aggregates (sand, gravel), cement, and water mixed in proportion. During transport, the wet mix is continuously stirred slowly to prevent initial setting and segregation of the concrete. However, the time from production to pouring generally should not exceed 1.5 hours to avoid concrete setting. Therefore, for long-distance transport, dry mix and semi-dry mix transport vehicles are used. Dry mix transport vehicles can load dry aggregates and cement directly into the mixing drum in proportion. During transport, the dry materials are mixed inside the drum, and water is added just before arriving at or upon reaching the construction site to complete the concrete mixing. Semi-dry mix transport vehicles carry concrete where aggregates and cement are proportionally prepared and contain some water, but the water content is insufficient for pouring. Water is added just before arriving at or upon reaching the construction site for mixing.