In construction projects, concrete mixers are the core equipment for preparing concrete. Their types can be divided into many types according to the mixing principle, structural form and applicable scenarios.

Common types of construction concrete mixer
Concrete mixers can be divided into two categories according to the mixing principle: self-falling type and forced type. The core difference between the two lies in the mixing power of the materials (gravity vs. mechanical force), and the applicable scenarios are significantly different.
1. Self falling concrete mixer
Principle: Relying on the rotation of the mixing drum, the materials (cement, sand, gravel, water) are lifted to a certain height through the blades on the inner wall of the drum, and then fall freely by gravity, and the mixing is achieved through repeated cycles.
Features: Simple structure, low energy consumption, but weak mixing intensity, only suitable for "plastic concrete" with good fluidity (large slump), poor mixing uniformity, and low efficiency.
Common series:
- JZC series: drum type, gear transmission, drum forward mixing, reverse discharging, small size, easy to move (with tires), suitable for small batch projects such as rural house construction and small municipalities, common model JZC350 (single mixing 350L).
- JZM series: friction drive drum type, the drum is driven by the friction wheel to rotate, with low maintenance cost, but the transmission efficiency is slightly lower than the gear type, and the applicable scenarios are similar to JZC.

2. Forced concrete mixer
Principle: The mixing drum is fixed, and the mixing blades (or mixing shaft) rotating in the drum are used to force shear, flip and squeeze the materials to achieve high-intensity mixing.
Features: good mixing uniformity and high efficiency, can mix dry hard concrete (slump ≤ 10mm), lightweight aggregate concrete (such as ceramsite concrete), etc., is the core equipment of large and medium-sized projects and commercial concrete mixing plants.
Common series:
- JD series (single horizontal shaft): single horizontal mixing shaft, spiral blades are installed on the shaft, the material is forced to push and mix in the axial and radial directions, compact structure, suitable for small and medium-sized prefabrication plants or temporary projects, models such as JD500 (single 500L).
- JS series (twin shaft): two parallel horizontal mixing shafts, staggered blades, highest mixing intensity, the most widely used forced type (focused on below).
- JDC series (single motor forced type): small forced type, single motor drive, suitable for laboratory or small batch special concrete mixing, such as JDC350.

JS series construction concrete mixer machine is the most mainstream forced concrete mixer in construction projects (especially large and medium-sized projects) and commercial concrete mixing plants, with "uniform mixing, high efficiency, and wide application range" as its core advantages.
1. Basic structure
The core structure of the JS series includes:
- Mixing drum: fixed square or trough-shaped drum (no rotation), inner wall wear-resistant lining (high manganese steel material, extended life).
- Twin shaft: two horizontal parallel mixing shafts, with mixing blades staggered on the shaft (blade angle and spacing optimized) to ensure no mixing dead angle.
- Transmission system: The motor drives the double shafts to rotate in opposite directions through a reducer (gear or planetary reducer) (the speed is usually 15-30r/min), and the power transmission is stable.
- Discharging mechanism: A hydraulic (or pneumatic) discharging door is installed at the bottom of the barrel to control the discharging speed (0-30 seconds/batch) to meet different casting requirements.
- Control system: PLC automatic control (or manual control), which can set the mixing time, automatic loading/unloading, and large models support linkage with the mixing station management system.

2. Working principle
When the double horizontal shafts rotate in opposite directions, the mixing blades on the shafts (including spiral blades, scrapers, counter blades, etc.) have a triple effect on the materials in the barrel:
- Radial shear: The blades are staggered into the material to form shear force and break up lumps (such as cement lumps);
- Axial convection: The spiral angle of the blades pushes the material to circulate left and right along the axial direction to avoid local accumulation;
- Flip mixing: The blades lift the material up and then throw it down to achieve uniform mixing in three-dimensional space.
The entire process (mixing + unloading) can be completed within 60-90 seconds, and the mixing uniformity (mortar density deviation) is ≤3%, which is much higher than that of a self-falling mixer.

3. Models and capacity
JS series models are named after "single mixing volume (L)", and common models and capacities are as follows:
- JS500: single mixing 500L, theoretical capacity 25-30m³/h (25-30 cubic meters per hour), suitable for small mixing plants or medium-sized construction sites;
- JS1000: single mixing 1000L, capacity 50-60m³/h, the basic model of mainstream commercial mixing plants;
- JS2000: single mixing 2000L, capacity 100-120m³/h, used for large mixing plants (annual capacity of more than 100,000 m³);
- Larger models such as JS3000 (3000L) and JS4500 (4500L) are suitable for super-large projects (such as high-speed railways and hydropower stations).

4. Core advantages
- Wide application range: It can mix almost all types of concrete, such as plastic concrete, dry hard concrete, lightweight aggregate concrete, fiber concrete (such as steel fiber, polypropylene fiber), etc., to meet the preparation requirements from ordinary C30 to high-strength C80 concrete.
- Excellent mixing quality: The double-axis blade has a dead angle design, and with the wear-resistant liner, even dry hard concrete (low sand ratio, high aggregate) can be mixed evenly to avoid "segregation" (sand and gravel sinking, cement slurry floating).
- Flexible capacity matching: From small (JS500, to meet the needs of rural centralized housing construction) to super large (JS4500, to meet the needs of high-speed rail box girder prefabrication), it can be used alone or as a mixing station host (with batching machine, cement silo) to form an automated production line.
- Strong durability: The mixing shaft and blades are made of high-chromium cast iron (HRC55-60), the bearing seat is equipped with a sealing system (to prevent cement slurry from penetrating), the mean time between failures (MTBF) is ≥800 hours, and it is suitable for high-intensity continuous production.

5. Applicable scenarios
- Large and medium-sized construction projects (such as high-rise buildings, bridges, and tunnels);
- Commercial concrete mixing plants (ready-mixed concrete production);
- Prefabricated component plants (such as pipe piles, floor slabs, and sleeper production);
- Special concrete preparation (such as self-compacting concrete and lightweight foamed concrete).

The JS series twin-shaft construction concrete mixer has become the core equipment of modern concrete production with its characteristics of "high efficiency, uniformity, and durability". It is the best choice to replace self-falling and single-shaft mixers, especially in scenarios with high requirements for concrete quality and production capacity.