Rubber Inflatable Core Molds are expandable and retractable cylindrical bags made by vulcanizing rubber with a fiber-reinforced layer, offering high tensile strength, elasticity, and airtightness. They are used to form hollow cavities in concrete components. During the production of hollow structures, the mold is placed in the center and filled with compressed air. Once inflated, it has sufficient strength to withstand the pressure of the concrete, replacing traditional wood, bamboo, and steel molds. Upon opening the valve, the capsule retracts and can be removed from the cavity. Easy to use, cost-effective, and durable, these molds can be reused multiple times. Deflated, they can be softly retracted, folded, or curled. They are suitable for creating holes in reinforced concrete structures, including piles, trusses, roof panels, columns, beams, construction projects, and hydraulic engineering (shipyards, shipways, docks). Construction practices have proven that the capsule hole-punching process is simple, saves materials, and offers versatile shapes such as circular, elliptical, rectangular, arch, octagonal, trapezoidal, and more. It can also create straight holes and variable cross-section holes, allowing for lightweight, thin-walled hollow structures and altering the properties of concrete, thus replacing rigid formwork. This is a cost-reducing and time-saving concrete product for construction projects.
Manufacturing Process:
Rubber inflation cores, in terms of manufacturing, early production models were all cold bonding processes. Over time, through continuous practice, the cold bonding process was gradually replaced by a single molding process using heat pressing and vulcanization. However, some manufacturers still use this method due to its relatively lower production costs. The critical drawback of the cold bonding process for inflation cores is that the adhesive joints can fail when overheated, significantly reducing their service life compared to those produced by the single molding process using heat pressing and vulcanization.
The rubber and anti-stretch fabric are heat-pressed and vulcanized into a single mold, ensuring a smooth surface without seams and capable of withstanding adequate concrete heat and pressure.
Next, variations in production techniques and the selection of raw materials greatly affect the quality of the rubber inflation cores. This includes choices between natural and synthetic rubber, as well as the tensile strength of the fabric. These factors directly impact the quality and lifespan, or the number of cycles, of the inflation cores.
Construction Method:
1. Place the core mold inside the reinforcing cage, ensuring the longitudinal joints face up. Inflate to the specified pressure and close the valve. To prevent concrete from floating upwards during vibration, the top, bottom, left, and right sides must be secured according to the construction process. Use formwork tie bolts to apply pressure to counteract the upward float.
2. Use a high-frequency inserted vibrator for concrete pouring, performing vibration simultaneously from both sides to prevent the core mold from shifting left or right. The tip of the vibrator must not touch the core mold to avoid piercing and causing air leakage.
3. Once the concrete has initially set, the core mold can be removed, and the mold can be demolded (open the vent valve).
