Production Method of House Prefabricated Slabs
The production method of house prefabricated slabs mainly includes steps such as mold preparation, steel reinforcement framework arrangement, foam board placement (for some slabs), additional steel reinforcement arrangement (for some slabs), steel reinforcement stretching, concrete pouring, curing, and subsequent processing.
Mold Preparation: Workers first form a mold by surrounding steel plates and secure the shape by tightening screws. Subsequently, a mold release agent is sprayed on the inner wall of the mold. This step aims to prevent the subsequently poured concrete from adhering to the mold, ensuring smooth demolding of the prefabricated slab after it is formed.
Steel Reinforcement Framework Arrangement: First, lay the first layer of the steel reinforcement framework, namely the distribution bars, whose dimensions must precisely match the mold to ensure structural stability. Then, workers lift the steel strands and thread them through one end of the mold to the other, combining them with the distribution bars as load-bearing bars to enhance the load-bearing capacity of the prefabricated component. Finally, anchorages are installed on both sides of the steel strands, with a diameter of approximately 3 centimeters, to fix the position of the steel strands.
Foam Board Placement (for Some Slabs): For prefabricated slabs requiring thermal insulation or heat insulation, workers place large foam boards with a thickness of up to 15 centimeters precisely into the mold and connect them with iron hooks to fix their shape and prevent displacement during pouring.
Additional Steel Reinforcement Arrangement (for Some Slabs): Lay another layer of the steel reinforcement framework on the foam board and thread in a dozen or so soft steel strands. At this point, the steel strands have not been stretched and have low strength, requiring enhancement through subsequent processes.
Steel Reinforcement Stretching: Adopt the pre-tensioning or post-tensioning process. The pre-tensioning process uses specialized equipment to stretch the steel strands to their ultimate strength, and after tightening, the second layer of concrete is poured. After the concrete solidifies, the tensile force of the steel reinforcement is permanently 'locked' within the slab. The post-tensioning process involves pouring the concrete first, and after it solidifies, the steel reinforcement is stretched. Although the procedures of the two methods differ, their essence is to enhance the strength of the prefabricated slab through steel reinforcement prestressing.
Concrete Pouring: After preparing the concrete, build a special track in mid-air and automatically pour the concrete using a mid-air tanker to reduce heavy manual labor. Workers control the tanker to pour the concrete into the mold and then vibrate it with a vibrating rod to expel air bubbles and prevent concrete cracking.
Curing: After demolding, the prefabricated slabs are hoisted to the basement for steam curing for 4 hours. The high-temperature steam accelerates the hydration reaction of the concrete, causing it to harden rapidly and reach the designed strength.
Subsequent Processing: After curing is complete, loosen the previously tensioned steel strands, gently lift the prefabricated slab by hooking its four corners with a gantry crane to complete demolding. Finally, use an angle grinder to cut off the excess steel reinforcement at both ends to make the edges of the prefabricated slab flat and facilitate installation.
