UHPC Thin Shell Repair for Concrete Corrosion

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Solution Overview

Problem

Reinforced concrete structures deteriorate due to corrosion of embedded reinforcement, leading to cracking and reduced service life, particularly in harsh environmental conditions, necessitating inefficient and costly repair methods.

Innovation Solution

Attaching a thin shell of ultra-high performance concrete (UHPC) over damaged areas, followed by filling the space between the shell and the structure with a bonding agent like grout or epoxy, which provides structural reinforcement and protection against corrosive agents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional concrete is used, then it provides basic structural support, but it allows chloride penetration and reinforcement corrosion leading to cracking and deterioration

Engineering Contradiction:

Improveprotection against chloride intrusionVSAvoidchloride penetration and corrosion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses ultra-high performance concrete (UHPC) as a composite material with optimized composition including silica fume, steel fibers, and superplasticizers to achieve extremely low permeability and high durability, creating a barrier that prevents chloride penetration while maintaining structural integrity

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies a thin shell of UHPC specifically to the surface exposed to harsh environments (chloride-containing solutions), providing enhanced protection only where needed rather than throughout the entire structure, thus preventing chloride intrusion at the critical interface

Inventive Principle:

Principle #3Local quality

2Ease of repair

If traditional repair methods are used, then damaged areas can be restored, but the process is time-consuming and costly

Engineering Contradiction:

Improverepair efficiencyVSAvoidrepair time

Core Design Contradiction:

Ease of repairVSLoss of time

Solution Approach 1:

The patent employs pre-fabricated UHPC shells that are manufactured off-site with precise geometry and attached to the structure in a single operation, eliminating the need for time-consuming on-site concrete pouring and curing processes while ensuring high-quality repair

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent utilizes the high flowability and rapid setting properties of UHPC mixtures, achieved through optimized water-to-binder ratios and superplasticizer content, enabling quick placement and early strength gain that dramatically reduces repair time

Inventive Principle:

Principle #35Parameter changes

3Strength

If a thick layer of repair concrete is applied, then structural integrity can be restored, but the added weight and complexity increase

Engineering Contradiction:

Improvestructural integrityVSAvoidweight of repair material

Core Design Contradiction:

StrengthVSWeight of stationary object

Solution Approach 1:

The patent employs thin-shell structures made of UHPC that leverage the material's extremely high compressive strength and tensile toughness (from steel fibers) to provide robust structural reinforcement with minimal thickness, significantly reducing the weight compared to traditional thick concrete repairs

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent uses UHPC's composite composition with steel fibers dispersed throughout the matrix to achieve exceptional strength-to-weight ratio, allowing thin sections to provide the same or greater structural integrity than much thicker layers of conventional concrete

Inventive Principle:

Principle #40Composite 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 effectively stops chloride intrusion, enhances structural integrity, and extends the service life of concrete structures by providing a strong, durable, and impermeable barrier against environmental corrosion, facilitating quick and cost-effective repairs.

Implementation Method 1

filling the space between the shell and the structure with a bonding agent like grout or epoxy

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

both the initiators (generally, chloride ion) and the supporters (for example, oxygen) of corrosion of the reinforcing steel must diffuse through the overlying concrete to the steel

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentUS10196832B2High performing protective shell for concrete structures

Publication Date: 2019.02.05 FLORIDA INTERNATIONAL UNIVERSITY

AI summary

The subject invention provides materials and methods for repairing and/or improving the performance of concrete structures. In preferred embodiments, the methods comprise attaching a thin shell of ultra-high performance concrete (UHPC) over the area of interest, the shape of the shell substantially conforming to that of the area itself, and subsequently filling a cavity defined by the shell with UHPC.