Two-Layer Bituminous Joint Seal for Vertical Concrete Walls

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Solution Overview

Problem

Bitumen-based joint seals are ineffective for vertical joints in concrete protective walls due to low viscosity and difficulty in remaining in place, leading to drainage and detachment issues, while alternative materials like polysulfides and polyurethanes are costly.

Innovation Solution

A two-layer joint seal comprising a bituminous first composition and a titanium dioxide-containing bituminous second composition, with a specific ratio of layer thickness and composition, providing improved adhesion and durability to prevent corrosion and leaks in vertical joints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If bitumen-based joint seals are used for vertical joints, then cost is reduced, but the seal drains out and detaches due to low viscosity

Engineering Contradiction:
ImprovecostVSAvoidseal retention
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies composite materials by combining bitumen with elastomers (such as styrene-butadiene copolymers or polyethylene cross-linked with silane), powdered mineral fillers, and fibrous fillers to create a joint seal composition that maintains the cost advantages of bitumen while achieving the viscosity and adhesion properties needed for vertical joint retention

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the physical and chemical parameters of the bitumen-based composition by controlling the softening point (80°C to 120°C), viscosity, and compositional ratios of elastomers (2% to 10% by weight) and mineral fillers (7% to 25% by weight) to optimize the balance between cost and seal retention performance

Inventive Principle:
Principle #35Parameter changes

2Reliability

If polysulfides or polyurethanes are used for vertical joints, then seal retention is improved, but cost increases

Engineering Contradiction:
Improveseal retentionVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive materials like polysulfides and polyurethanes with a cost-effective bitumen-based composition that achieves comparable performance through optimized formulation, making the joint seal both economical and reliable for vertical applications

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent adjusts key parameters including softening point (80°C to 120°C), elastomer content (2% to 10% by weight), and mineral filler content (7% to 25% by weight) to create a bitumen-based material that matches the retention properties of expensive alternatives while maintaining cost advantages

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If bitumen joint tape is used for vertical joints, then cost is reduced, but the tape detaches due to its own weight

Engineering Contradiction:
ImprovecostVSAvoidadhesion strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent changes the physical state from a thin tape form to a molded or extruded profile form with increased cross-sectional area, and adjusts the compositional parameters (elastomer content, mineral filler content, softening point) to achieve sufficient adhesion strength that overcomes the weight of the joint seal itself

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials incorporating elastomers and fibrous fillers to enhance the mechanical strength and adhesion properties of the bitumen-based composition, enabling it to support its own weight in vertical applications without detachment

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3081615B9Closing joint for a groove with least one layer of a bituminous first and second mass
Publication Date: 2020.12.02 DENSO HOLD GMBH & CO
  • EP3081615B9 patent drawingFigure 1
  • EP3081615B9 patent drawingFigure 2~3
  • EP3081615B9 patent drawingFigure 4~5

AI summary

Joint sealant for a joint, comprising at least one layer of a bituminous first mass and at least one layer of a bituminous second mass, wherein the at least one layer of the second mass is arranged on the at least one layer of the first mass and forms an exposed surface, wherein the ratio of a layer thickness of the first mass and the second mass is in a range of about 250:1 to about 1:1, and wherein, unlike the first mass, the second mass comprises about 10 wt.% to about 40 wt.%, based on the total amount of the second mass, titanium dioxide.