How to Produce Prefabricated Concrete Houses
The production of prefabricated concrete houses involves five core processes: material preparation, mold making, pouring and curing, mold removal and quality inspection, and transportation and assembly. The specific process is as follows:
1. Material Preparation and Inspection
Selecting raw materials that meet standards is fundamental: P.O42.5 ordinary Portland cement should be used for cement to ensure stability compliance; for sand and gravel, medium-coarse sand (with a mud content ≤ 3%) and 5-20 mm crushed stone (accounting for 60%) should be selected to ensure reasonable grading; for steel bars, HRB400 deformed steel bars (with a diameter of 8-14 mm) should be used, and their tensile strength should be tested. All materials need to be sampled and inspected to avoid structural safety issues caused by material defects. Some enterprises may add polypropylene fibers to enhance the crack resistance of concrete or use 3D printing technology to produce special-shaped components to improve design flexibility.
2. Mold Making and Embedding
The precision of the mold directly affects the dimensions of the components: 5 mm thick steel plates are used to weld wall molds, with release agents applied to the inner walls to prevent adhesion and sealant used at the joints to ensure a diagonal deviation ≤ 3 mm. Positioning devices for water and electricity pipelines and plastic-steel window frames need to be embedded in the mold to avoid structural damage from later slotting. The mold design should consider both the ease of mold removal and the functionality of the components, such as reserving bolt holes or connector slots.
3. Pouring and Curing Process
Concrete performance is crucial: First, arrange the steel bar framework, then mix the concrete using a forced mixer (with a water-cement ratio controlled between 0.45-0.5), and eliminate air bubbles by vibrating with a vibrating rod for 20-30 seconds to ensure density. After pouring, cover with plastic film for moisture retention. In winter, steam curing should be used to maintain a temperature ≥ 20°C. Under normal temperature, curing for 7 days can achieve 70% of the design strength, and full compliance is achieved after 28 days, during which the components should not be disturbed.
4. Mold Removal and Quality Inspection
After the curing period is over, remove the mold and test the wall strength with a rebound hammer to ensure compliance with design requirements. Qualified components need to have burrs trimmed and their surface flatness and the positions of embedded parts checked. The quality inspection process should strictly record data, and non-conforming products should be reworked or scrapped to prevent hidden dangers from entering the next process.
5. Transportation and On-site Assembly
For transportation, use special flatbed trucks, install rubber pads between modules to prevent collisions, and secure them firmly to avoid displacement. During on-site installation, check the positions of foundation embedded parts, connect the walls to the foundation with high-strength bolts, and fill the joints with repair mortar to ensure sealing. After assembly, check the overall verticality and levelness to ensure the structural stability of the house.
