Hydrogel Formwork Coating for Concrete Edge Quality

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Solution Overview

Problem

The quality of concrete edge zones is compromised due to uneven water-cement ratios and porosity issues, leading to reduced strength and visual imperfections, as existing formwork materials either trap excess water or cause concrete to adhere and break during demolding.

Innovation Solution

A hydrogel-based agent is applied to the formwork surface, which absorbs and regulates excess mixing water, forming a dense film that controls the water-cement ratio, prevents concrete adhesion, and enhances surface texture, acting as both a release agent and improving hydration conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If non-absorbent formwork is used, then the formwork surface is easy to clean and reuse, but excess mixing water cannot diffuse into the formwork leading to increased water-cement ratio, lower concrete strength, and increased porosity in the edge zone

Engineering Contradiction:
Improveformwork reusabilityVSAvoidconcrete edge zone strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The formwork surface is treated with a hydrogel-based agent that creates a localized water-regulating layer only at the concrete-contact interface. This allows the bulk formwork to remain non-absorbent and reusable while the surface layer selectively absorbs excess water from the concrete edge zone, improving local water-cement ratio control without compromising overall formwork reusability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The agent combines hydrogel particles with a carrier system (such as a soluble binder or adhesive mixture) to create a composite coating that adheres to the formwork surface. The hydrogel provides water absorption capability while the carrier ensures proper adhesion and controlled release, creating a functional composite layer that addresses both water regulation and formwork protection.

Inventive Principle:
Principle #40Composite materials

2Strength

If absorbent formwork is used, then water is extracted from the concrete edge zone improving water-cement ratio, but concrete adheres to the formlining and may break during demoulding

Engineering Contradiction:
Improveconcrete edge zone strengthVSAvoidconcrete adhesion to formwork
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The hydrogel-based agent acts as an intermediary layer between the formwork and concrete. It selectively absorbs excess water from the concrete edge zone to improve water-cement ratio, while simultaneously providing a non-sticking surface that prevents concrete adhesion to the formwork. This mediator function resolves the contradiction by decoupling the water absorption function from the adhesion problem.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The agent changes the surface properties of the formwork by creating a hydrogel coating with specific water absorption characteristics. This parameter change allows the formwork surface to dynamically regulate water content in the concrete edge zone while maintaining a non-sticking property, thus improving strength without causing adhesion issues.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If excess mixing water is present in the concrete edge zone, then hydration can occur, but water-cement ratio increases leading to lower concrete strength and increased porosity with sanding tendency

Engineering Contradiction:
Improvehydration completenessVSAvoidconcrete edge zone strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The hydrogel-based agent provides a feedback mechanism for water regulation in the concrete edge zone. The hydrogel particles continuously monitor and respond to water content by absorbing excess water when the water-cement ratio becomes too high, and releasing water when hydration is insufficient. This dynamic feedback control maintains optimal water-cement ratio and prevents both over-hydration and under-hydration conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The hydrogel coating creates a controlled porous structure on the formwork surface that allows selective water transport. The porous nature of the hydrogel enables it to absorb excess water from the concrete edge zone while maintaining connectivity for water distribution, thus regulating water-cement ratio without completely blocking water penetration needed for hydration.

Inventive Principle:
Principle #31Porous materials

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

This method ensures a uniform, pore-free concrete surface with improved strength and visual quality by regulating water content, eliminating rework due to adhesion issues and providing a hydrophobic finish without additional treatments.

Implementation Method 1

the hydrogel is able to absorb excess mixing water in the concrete with an increase in volume

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

At least one hydrogel (5) is applied flatly to a side (2, 3) of a formwork (1, 2) facing the concrete

Methodology Applied
Scientific EffectHydrogel: Hydrogel

Implementation Method 3

Should additional water be required at a later point in time for complete hydration in the concrete edge zone, the hydrogel is able to release the stored water back into the concrete

Methodology Applied
Scientific EffectWater release:

Implementation Method 4

The agent forms a full-surface, dense film on the formwork surface

Methodology Applied
Scientific EffectFilm formation:

Implementation Method 5

the film that forms creates a separating effect between the concrete and the formwork, which prevents the concrete from sticking to the surface of the formwork as it hardens

Methodology Applied
Scientific EffectSeparating effect:

Data Source

PatentEP2760653B1Method for producing components having a high-quality concrete edge zone and concrete surface
Publication Date: 2017.08.02 H BAU TECHN
  • EP2760653B1 patent drawingFigure 1~2

AI summary

The invention relates to means for applying to the shuttering face (3) of concrete shuttering (2) for producing concrete components having a high-quality concrete edge zone, wherein the means has a hydrogel (5) as a substantial constituent. Automatic regulation of the water-cement ratio in the concrete edge zone and therefore an improvement in the concrete and surface quality are achieved therewith.