Precompressed Expansion Joint Sealing Without Dust-Generating Surface Grinding

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Solution Overview

Problem

Existing expansion joint sealing systems face challenges in maintaining watertight and fire-resistant seals in dynamic environments, require on-site assembly, and generate harmful dust during installation, leading to health risks and increased labor costs.

Innovation Solution

A precompressed expansion joint sealing system using a core of open-celled polyurethane foam treated with water-resistant and fire-resistant materials, applied without mechanical grinding or abrading, and secured with a liquid sealant to accommodate structural movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If mechanical grinding or abrading is used to prepare substrate surfaces, then adhesion strength is improved, but harmful dust is generated causing health risks

Engineering Contradiction:
Improveadhesion strengthVSAvoidharmful dust
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The substrate surfaces are pre-treated with a primer or bonding agent before applying the sealant, creating a preparatory layer that enhances adhesion without requiring mechanical abrasion. This preliminary chemical treatment replaces the need for dust-generating mechanical surface preparation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The mechanical grinding and abrading process is replaced with a chemical or adhesive-based surface preparation method. Instead of using mechanical force to create surface roughness for adhesion, the invention uses chemical primers or specialized bonding agents that create strong adhesion without mechanical contact, thereby eliminating harmful dust generation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If on-site assembly is required for sealing systems, then adaptability to different joints is improved, but labor costs and installation time increase

Engineering Contradiction:
Improveadaptability to different jointsVSAvoidinstallation speed
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The sealing system is divided into modular components that can be independently manufactured and then assembled on-site. This segmentation allows each component to be optimized for specific joint types while maintaining overall system flexibility, enabling rapid assembly without requiring complex custom fabrication for each joint configuration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing system incorporates adjustable parameters such as expandable foam cores or flexible sealing elements that can be configured to match different joint widths and movement requirements. This allows a single standardized product line to adapt to various joint specifications, eliminating the need for custom on-site fabrication while maintaining versatility.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If precompressed expansion joint sealing systems are used, then installation simplicity is improved, but accommodation of structural movement may be limited

Engineering Contradiction:
Improveinstallation simplicityVSAvoidmovement accommodation capability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The sealing system incorporates dynamic elements such as expandable foam cores or bellows-like structures that can actively respond to structural movements. These dynamic components maintain sealing effectiveness throughout the range of motion, allowing the precompressed system to adapt to various movement magnitudes while retaining installation simplicity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sealing system uses materials or structures with variable properties, such as foam that changes density or expandability in response to compression and movement. This allows the precompressed system to maintain its sealing function across different joint conditions and movement ranges, bridging the gap between installation simplicity and movement accommodation capability.

Inventive Principle:
Principle #35Parameter changes

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 system provides a safer, dustless installation method that maintains watertight and fire-resistant seals, adheres without surface preparation, and meets UL 2079 testing standards for movement and fire endurance.

Implementation Method 1

the precompressed expansion joint sealing system expands outwardly toward the opposing surfaces, embeds within the mounting band of sealant

Methodology Applied
Scientific EffectElastic expansion: Elasticity

Implementation Method 2

secured with a liquid sealant to accommodate structural movements

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 3

A precompressed expansion joint sealing system uses a core of open-celled polyurethane foam

Methodology Applied
Scientific EffectFoam expansion: Foam

Data Source

PatentEP4281627B1Safer dustless method for installing a precompressed expansion joint sealing system
Publication Date: 2026.03.04 SIKA TECH AG
  • EP4281627B1 patent drawingFigure 1A~1C
  • EP4281627B1 patent drawingFigure 2A~2B
  • EP4281627B1 patent drawingFigure 2C~2D

AI summary

Disclosed is a safer, dustless method for installing an expansion joint sealing system without mechanically grinding substrates to improve adhesion. The method includes locating substrates forming a gap between opposing surfaces of the substrates, preparing the surfaces by wiping with a solvent, and applying a mounting band of sealant to the surfaces. The method includes disposing the sealing system in the gap proximate to or within the mounting band, maintaining the sealing system in the gap until the system expands toward the surfaces, embeds within the mounting band and secures the sealing system in position between opposing surfaces. The method also includes prior to the preparing the surfaces, removing an existing joint sealing system by cutting sealant between the existing system and the substrates, wiping surfaces with solvent, and leaving any deformation or embedded residue from the removed sealing system on or embedded in the surfaces of the substrates.