Ready-mix concrete refers to concrete that is centrally mixed in a factory or workshop and delivered to the construction site. It consists of cement, aggregates, water and admixtures, mineral admixtures and other components in a certain proportion, which are measured, mixed and sold at the mixing plant and transported to the place of use within a specified time by means of a transport truck.
There are three types of ready-mixed concrete plants: stationary, semi-mobile and mobile.
The plant is larger in scale, with an output of 100-120m³ per hour. Fixed ready-mixed concrete plants can be divided into single-stage and double-stage plants according to the process flow. A typical single-stage plant is a concrete mixing building, usually divided into five or six floors, with the process flowing from top to bottom. At the top is the storage layer, where various aggregates and cement are brought in and stored in separate hoppers. Water is piped into the water tank. The lower layer is the batching layer, with a control room and automatic batching scales, where cement, various aggregates and water are weighed in proportion to each other. The mixing layer is equipped with a mixer, and the raw materials are discharged into the mixer through the hopper and then discharged into the discharge hopper, which leads to the bottom layer and is loaded into various transport vehicles; it is transported to the grouting site. ②The double-stage plant is characterised by low silos and the raw materials are lifted in two stages. The height of the plant is reduced, the layout is flexible and investment can be saved.
Generally simple plants are used and production equipment can be disassembled and reassembled after transfer. The output is generally 60-80 cubic metres per hour.
There is no mixing system in the plant. The storage, weighing and transfer systems for sand, stone and cement are assembled in a steel structure. The mix is loaded into a concrete mixing truck, filled with mixing water and transported to the construction site as it goes.
The commercial concrete is usually mixed in a designated factory and transported to the site by a mixer truck and then transported to the designated place by a ground pump, whereas ready-mixed concrete is mixed in a designated place on site and then transported by crane or bucket truck.
Ready-mixed concrete is mostly mixed on site, using coarse rock aggregates of 5mm in size and other materials such as sand for mixing, and the composition and content of some materials can be controlled by themselves; whereas commercial concrete can only be mixed with fine aggregates of about 2.5mm in size due to the restrictions of the transport pump, and the controlled raw materials must be in strict proportion, which is difficult to change. .