How to Make Prefabricated House Slabs

The manufacturing process of prefabricated house slabs mainly includes steps such as mold making, steel bar erection, concrete pouring, curing, and demolding and processing. Details are as follows:

Mold Making: Workers first form a large mold that meets the size requirements of the prefabricated slab by surrounding steel plates. After tightening the screws for fixation, they spray a layer of mold release agent on the inner wall of the mold. The purpose of this step is to prevent the subsequently poured concrete from adhering to the mold and ensure that the prefabricated slab can be smoothly demolded after forming.

Erection of Distribution Bars: The first layer of steel bar framework (distribution bars) is precisely erected into the mold according to the mold size to ensure a tight fit between the steel bars and the mold. Distribution bars mainly play a role in dispersing loads and enhancing the overall integrity of the prefabricated slab.

Laying of Bottom-Layer Concrete: On the erected distribution bars, workers evenly lay a layer of concrete about four centimeters thick as a base layer. This layer of concrete provides basic support for the subsequent structure and ensures the bonding performance between the steel bars and the concrete.

Placement of Foam Boards: Giant foam boards with a thickness of 15 centimeters are tightly placed into the mold. The foam boards are connected and fixed with iron hooks to prevent displacement during concrete pouring. The function of the foam boards is to reduce the self-weight of the prefabricated slab while forming an internal cavity structure to improve thermal insulation performance.

Erection of Load-Bearing Bars: A second layer of steel bar framework is laid on the foam boards, and dozens of high-strength steel strands (load-bearing bars) are threaded through. Steel strands have extremely high tensile strength and are the key structure for the prefabricated slab to bear loads.

Pretensioning Process: Special equipment is used to stretch each steel strand to its ultimate strength. After the steel bars are tightened, the second layer of concrete is poured. Once the concrete is completely solidified, the tensile force of the steel bars is permanently 'locked' into the slab body, forming a prestressed structure and significantly improving the crack resistance and load-bearing capacity of the prefabricated slab.

Vibration and Air Exhaust: After pouring is completed, workers use a vibrating rod to fully vibrate the concrete to expel internal air bubbles, avoiding structural cracking or strength reduction caused by air bubbles.

Steam Curing: The prefabricated slabs are sent to a basement for up to 4 hours of steam curing. The high-temperature and high-humidity environment accelerates the hydration reaction of the concrete, making it harden quickly and ultimately reach the designed strength.

Demolding and Processing: After curing is completed, the steel strands are loosened. The prefabricated slab is lifted and demolded by hooking its four corners with a gantry crane, and then the excess steel bars at both ends are cut off with an angle grinder to complete the final processing.