Jingtong Rubber Culvert Balloon Mandrel for Railway Bridges Inflatable Rubber Core Mold

• Customization: Available
• Condition: Used
• Certification: ISO9001, ISO
• Model NO.: JTXM-001
• Usage: Tunnel, Bridge, Culvert
• Material: Natural Rubber
• Shape: Oval
• Diameter: Diameter 50mm-2500mm
• Length: 0.5m-50m
• Application: Bridge, Culvert, Tunnel, Pipe
• Color: Black
• Payment: 100% Tt
• Thickness: 3mm
• Using: 60times
• Transport Package: in Roll on Pallet with PE Film
• Specification: dia600/900/1200/1500mm
• Trademark: HengJingGong
• Origin: Hebei
• HS Code: 4016950090
• Production Capacity: 1000PCS/30days
• Package Size: 50.00cm * 50.00cm * 50.00cm
• Package Gross Weight: 30.000kg

Product Description

Product Description

for Hollow Slabs
    The , also known as the bridge inflatable core mold, is an expandable and contractible cylindrical bag made of rubber with a fiber-reinforced layer, featuring excellent tensile strength, elasticity, and air-tightness. It is primarily used to form cavities in concrete components.

    When manufacturing hollow components, the is placed in the middle of the component and is expanded by injecting compressed air. The inflated core mold can withstand the pressure of concrete, thus effectively replacing traditional wooden, bamboo, and steel molds. When in use, simply open the valve, and the airbag will deflate, making it easy to remove from the cavity.

Function

    *Forming Core: Inflates to form precise internal cavities or holes during concrete pouring.
    *Pressure-bearing & Stability: Maintains a stable shape and sufficient internal pressure after inflation to resist the impact and lateral pressure of fluid concrete, preventing component deformation.
    *Easy Demolding: After the concrete reaches sufficient strength, it deflates and contracts, reducing in volume, allowing it to be easily pulled out from the component cavity, simplifying the demolding process.
    *Reusable: Designed for good durability, allowing a single core mold to be reused multiple times (e.g., some high-quality molds can be reused 60-80 times, or approximately 10 times depending on design and maintenance), making it cost-effective.

Product Features

*High Pressure Resistance: Working pressure 0.04-0.06MPa, burst pressure ≥0.15MPa

*Excellent Air Tightness: Pressure drop <3kPa in 24-hour test

*Optimal Flexibility: Easy to fold and store with good rebound

*Puncture Resistance: Surface puncture strength ≥80N

*Temperature Adaptation: Normal use in -20℃ to +60℃ environments

Cross-sectional shape of

Production Process

The production process of is divided into two types: cold bonding process and hot pressing vulcanization process.

    *The cold bonding process involves first processing the raw materials into sheets (or purchasing finished rubber sheets), then cutting them into corresponding pieces according to the shape of the , and finally adhering them together with adhesive to form the inflatable core mold.
    *The hot-press vulcanization process involves directly vulcanizing natural rubber under heat and pressure, combined with anti-tear fabric, to form the specified shape of the inflatable core mold in a single molding process without any seams.

Specification

item	index
thickness tolerance, mm	3.2±2
shore A	65±5
adhesive strengh N/25MM	≥8
tensile strength, mpa	≥12
elongation at break %	≥350
300% constant elongation,mpa	6
stretching deformation rate	≤20%
suitable temperature,ºC	-10-+80
appearance	no crack, no bubble, impurity length≤3mm depth≤1.5mm and no more than one place each meter

Installation

Product Details

Packaging & Shipping

Company Profile

    Hengshui Jingtong Rubber Co., Ltd., located in Hebei Province's Hengshui City, is a professional manufacturer of engineering rubber products. Our product range includes bridge bearings, expansion joints, water stop strips, water stop belts, inflatable cores, building deformation joint device and water plugs, which are widely used in bridge, tunnel, water conservancy, and power engineering projects. The company boasts advanced technology and mature processes to ensure reliable product quality.

    We have a professional technical team and a comprehensive after-sales service system to ensure customers receive high-cost-performance products and attentive service. Hengshui Jingtong Rubber Co., Ltd. is committed to continuous innovation to meet market demands and looks forward to esta  blishing long-term cooperative relationships with customers from both domestic and international markets.

FAQ

Q1: What is an inflatable core form and what is it used for?

A:A reusable rubber-nylon inflatable mandrel used to create hollow voids in concrete bridge girders, hollow slabs, culverts, and tunnels.

Q2: How many times can the core form be reused?

A:80-100+ reuse cycles with proper handling; high-strength rubber-nylon composite resists concrete pressure and abrasion.

Q3: What working pressure does it require during concrete pouring?

A:Typical working pressure 0.02-0.05 MPa; reinforced multi-layer cord fabric ensures no deformation under wet concrete load.

Q4: Can you customize the shape, diameter, and length?

A:Full OEM/ODM: round, oval, rectangular, trapezoidal shapes; diameter up to 2,000 mm, length up to 30 m.

Q5: How is it installed and removed?

A:Inflate into position before pouring; deflate and pull out after concrete sets -- simple, no crane disassembly needed.

Q6: What certifications do you provide?

A:ISO 9001/14001/45001 certified, manufactured under strict quality control with burst-pressure testing for every batch.

Q7: What surface finish does it leave and does it leak air during use?

A:Smooth inner cavity finish; multi-layer vulcanized construction ensures zero air leakage within rated working pressure.