Manhole Humidity Control to Prevent Reinforced Concrete Neutralization

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Solution Overview

Problem

Existing methods for suppressing concrete neutralization in reinforced concrete structures, such as those used in manholes, are either costly or undesirable due to surface processing concerns and have limited effectiveness, particularly for structures already in place, highlighting the need for a method to control humidity as a key factor influencing neutralization progression.

Innovation Solution

A humidity adjustment device and method that acquires humidity information within the manhole and controls it to maintain a specific range, preventing neutralization by ensuring humidity levels are above a reference value but below the critical humidity threshold to prevent dew condensation, using a system comprising a control unit, humidifier, and sensors to manage humidity levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the blending of concrete is changed to suppress neutralization, then the resistance to neutralization is improved, but the cost increases

Engineering Contradiction:

Improveresistance to neutralizationVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the environmental parameter (humidity) rather than the concrete material parameters (blending). By controlling the humidity in the closed space where concrete exists to be 60% or higher, the patent suppresses neutralization progression without requiring expensive concrete blending modifications, thus resolving the contradiction between improved neutralization resistance and increased cost.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If surface processing is applied to prevent carbon dioxide entry, then the neutralization prevention effect is improved, but the reliability decreases due to peeling by weathering

Engineering Contradiction:

Improveneutralization prevention effectVSAvoidservice life of surface processing

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent extracts the harmful factor (carbon dioxide) from entering the concrete by controlling the environmental humidity in the closed space, rather than applying surface processing that prevents CO2 entry. This eliminates the problem of surface processing peeling while maintaining neutralization prevention effectiveness.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If surface processing is applied to suppress neutralization, then the neutralization prevention effect is improved, but the safety decreases due to influence on human body

Engineering Contradiction:

Improveneutralization prevention effectVSAvoidinfluence on human body

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of high humidity (potential dew condensation) into a beneficial effect by precisely controlling humidity to be 60% or higher but below the dew condensation threshold. This suppresses neutralization while avoiding the harmful effects that would occur with uncontrolled high humidity, eliminating the need for potentially harmful surface processing.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS20230314018A1Humidity adjusting device and humidity adjusting method

Publication Date: 2023.10.05 NT T INC

AI summary

A humidity adjustment device (10) according to the present disclosure includes a control unit (11) that acquires humidity information indicating humidity of a space part of a manhole and controls the humidity on the basis of the humidity information.