Construction of Concrete Prefabricated Houses
The construction process of concrete prefabricated houses mainly includes five steps: foundation treatment, installation of foundation piles and splicing of crossbeams, module manufacturing and transportation, on-site assembly, and subsequent treatment.
Foundation Treatment: The foundation needs to be leveled and a cushion layer poured. For example, in a rural case in South Korea, the process starts with clearing weeds, leveling the foundation, and excavating foundation pits. Surveyors ensure that the excavation depth and ground height meet design requirements. After excavating about 60 centimeters, a white plastic sheet is laid, and then a concrete pump truck is used to pour the foundation. The white plastic sheet prevents moisture loss, promotes hydration reactions, enhances the strength and durability of the concrete, and no steel bars are used in the foundation. Another case involves digging a pit about 1 meter deep on the homestead, laying a moisture-proof PE film at the bottom, pouring 'discarded concrete' as the base, and installing a guide plate for positioning prefabricated concrete piles after solidification.
Installation of Foundation Piles and Splicing of Crossbeams: After the concrete solidifies, a base plate is installed, holes are drilled with a drill, and expansion screws are used for fixation to secure the foundation piles to the cushion layer. The foundation piles are prefabricated in advance, each weighing about 5 tons, and are installed using a mobile crane. Each corner of the piles has reserved holes for easy lifting. After six foundation piles are in place, crossbeams are installed. After horizontal measurement and adjustment, they are fixed with nuts, and then the gaps are filled with foam glue to support the fixation. The nut fixation points are sealed with cement to prevent rust and corrosion and extend the service life of the structure.
Module Manufacturing and Transportation: Module manufacturing is completed in the factory. For example, at the China State Construction Hailong Intelligent Construction Industrial Park, the ceilings, walls, and bathroom waterproof layers of the houses are manufactured in the factory, and scattered components are produced separately and then assembled. During manufacturing, workers assemble metal steel plates into molds using bolt connectors, spray mold release agents, place steel bars crosswise and tie them into a mesh framework, place connectors at symmetrical positions inside, fill with concrete, remove air bubbles with a vibrator, smooth the surface after pouring, cover with a plastic greenhouse, and heat it to promote hydration reactions. After the prefabricated concrete components required for construction are completed, they are transported to the construction site.
On-site Assembly: A crane lifts the prefabricated concrete house modules, and workers cooperate to accurately position them on the foundation, assembling them like building blocks. Each module has a detailed 'ID card', including the project name, product model, and production date. The positioning of each steel bar controls the error and precision in millimeters.
Subsequent Treatment: After the foundation piles and crossbeams are installed, the soil is backfilled and the foundation is poured to complete the frame structure. After module assembly, connection treatment may still be required, such as on-site cast-in-place connections at a construction site of a real estate project in Shanghai.
