Polyolefin Foam Formwork Panel Thermal Expansion
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Solution Overview
Problem
Existing formwork plates in concrete construction suffer from high thermal expansion, leading to issues with silicone joints being pressed out, allowing concrete to flow into gaps and cause flaking, and wood-based plates face swelling and rotting problems.
Innovation Solution
A formwork plate with a foam core made of polyolefin, supported by fiber-reinforced thermoplastic laminate layers, and covered with fiber-reinforced polyolefin outer layers, which are adhesive-free and thermally welded for enhanced stability and recyclability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If wood components are used in the formwork panel to reduce thermal expansion, then thermal dimensional stability is improved, but swelling resistance deteriorates due to water absorption
Solution Approach 1:
The patent uses a composite structure with a foam core comprising a polyolefin and support layers made of fiber-reinforced thermoplastic laminate. This composite material combination provides both thermal dimensional stability and swelling resistance, as the polyolefin foam core has low thermal expansion and the fiber reinforcement provides structural stability without the swelling issues of wood-based materials.
2Stability of the object's composition
If silicone joints are provided between the formwork panel and frame to compensate for thermal expansion, then thermal expansion compensation is improved, but reliability deteriorates due to silicone being squeezed out and concrete flowing into gaps
Solution Approach 1:
The patent changes the thermal expansion parameter of the formwork panel by using a foam core comprising a polyolefin with a thermal linear expansion coefficient of 80 to 150 µm/m/K, which is closer to the thermal expansion coefficient of aluminum frames (23 to 25 µm/m/K) than traditional materials. This reduces the thermal expansion difference between the panel and frame, minimizing the need for large silicone joints and preventing silicone squeeze-out.
3Ease of manufacture
If adhesive-free bonding is used to improve recyclability, then ease of manufacture and environmental compatibility are improved, but strength may deteriorate
Solution Approach 1:
The patent replaces the chemical bonding system (adhesives) with a thermal bonding system. The foam core and support layers are bonded together through thermal welding or heat fusion, which creates strong bonds without requiring adhesives. This allows the formwork panel to be easily disassembled and recycled by heating, while maintaining structural strength during use.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves reduced thermal expansion, improved swelling resistance, wear-resistant surfaces, and excellent nailability, resulting in smooth, homogeneous concrete surfaces and a circulatory, sustainable formwork plate that can be easily recycled.
Implementation Method 1
the foam core comprises a polyolefin... the formwork panel exhibits reduced thermal expansion
Implementation Method 2
The formwork panel therefore exhibits good swelling resistance when absorbing moisture
Implementation Method 3
the foam core, the supporting layers, and the outer layers are bonded to one another without adhesive
Data Source
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AI summary
The invention relates to a formwork panel (3) for the production of concrete and reinforced concrete structures, comprising a foam core (A) comprising a polyolefin, support layers (B) connected to the foam core (A) on both sides and each comprising a fiber-reinforced thermoplastic laminate, and outer layers (C) connected to the support layers (B) and each comprising a fiber-reinforced polyolefin. The invention further relates to a frame formwork element (1) comprising a frame (2) and a formwork panel (3) according to the invention.