Encapsulated Bacterial Healing Agents for Self-Healing Concrete

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Solution Overview

Problem

Existing self-healing concrete technologies face challenges in incorporating sufficient healing agents without compromising the workability and strength of the concrete mixture, limiting their application to high-strength constructions due to the volume requirements of healing agents, which often result in reduced concrete durability and structural integrity.

Innovation Solution

The development of leakage-proof tablets containing a particulate healing agent comprising bacterial material and additives, coated to protect during concrete production, which break and release the healing agent upon crack formation, allowing for higher quantities of healing agents to be used without affecting the concrete's workability or strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If higher quantities of healing agents are incorporated into concrete, then healing capacity is improved, but workability and strength of the concrete mixture deteriorate

Engineering Contradiction:
Improvehealing capacityVSAvoidconcrete strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The healing agent is segmented into encapsulated particles distributed throughout the concrete matrix. Each particle contains a small amount of healing agent (bacteria and nutrients) in a protected capsule, allowing many such particles to be distributed without the negative effects of bulk healing agent addition. This segmentation enables high healing capacity while maintaining concrete workability and strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The healing agent is enclosed in flexible capsule shells that protect the contents during concrete mixing and placement. These thin film encapsulations allow the healing agent to be incorporated in high quantities without affecting concrete properties, as the capsules maintain integrity during mixing but can rupture when needed to release the healing agent at crack sites.

Inventive Principle:
Principle #30Flexible shells and thin films

2Reliability

If higher quantities of healing agents are incorporated into concrete, then healing capacity is improved, but workability of the concrete mixture deteriorates

Engineering Contradiction:
Improvehealing capacityVSAvoidworkability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The healing agent is divided into numerous small encapsulated particles that can be uniformly distributed throughout the concrete mixture. This segmentation prevents the healing agent from interfering with concrete workability, as the small encapsulated particles do not disrupt mixing, pumping, or placement operations, yet provide substantial healing capacity when distributed throughout the structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flexible capsule shells enclose the healing agent in a form that does not interfere with concrete workability. The capsules remain intact during mixing and placement, allowing high quantities of healing agent to be incorporated without affecting the fluidity, pumpability, or finishability of the fresh concrete mixture.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If encapsulation material is used to protect healing agent during production, then protection is improved, but cost and manufacturing complexity increase

Engineering Contradiction:
Improveprotection during productionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The encapsulation material parameters are optimized to provide adequate protection during concrete production while maintaining cost-effectiveness. The capsule shells are designed with appropriate thickness, strength, and chemical resistance to protect the healing agent during mixing and placement, but without excessive complexity or cost. Simple single-layer or multi-layer polymer capsules provide sufficient protection for most applications.

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

This approach enables improved healing capacity and enhanced workability and strength of concrete, allowing for the use of self-healing concrete in structural applications that require high strength, while being technically easier and more cost-effective than previous methods.

Implementation Method 1

bacteria can produce that by metabolic conversion of a suitable organic component. The nature of metabolically produced filler material could be bio-minerals such as calcite.

Methodology Applied
Scientific EffectMetabolic conversion: Fermentation

Implementation Method 2

leakage-proof tablets containing the actual healing agent, coated to protect during concrete production

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Implementation Method 3

which break and release the healing agent upon crack formation

Methodology Applied
Scientific EffectFracture mechanics: Fracture Mechanics

Data Source

PatentEP2556037B1Healing agent for self-healing cementious material
Publication Date: 2017.11.01 GREEN BASILISK BV
  • EP2556037B1 patent drawingFigure 1
  • EP2556037B1 patent drawingFigure 2a~2b
  • EP2556037B1 patent drawingFigure 3

AI summary

The invention provides a process for the production of a cementious material. The process comprises mixing cement starting materials and a particulate healing agent to provide the cementious material. The healing agent comprises coated particles, wherein the coated particles comprise bacterial material and additive. The bacterial material is selected from the group consisting of a bacterium, a lyophilized bacterium and a bacterial spore of a bacterium. The present invention solves these problems, as (substantially leakage-proof) tablets containing the actual healing agent may neither interfere with either the workability of the liquid mixture ("cementious material") nor negatively affect properties of either mixture or final material (hardened concrete), even when applied in large quantities. During crack formation in cementious based constructions, the particles also crack, and healing agent is released.