Embedded Antenna Moisture Measurement in Concrete

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Solution Overview

Problem

Existing non-destructive moisture content measurement techniques for materials like concrete and mortar are costly, complex, and inaccurate, particularly when measuring core moisture levels, leading to prolonged construction times and increased costs due to safety margins.

Innovation Solution

A non-destructive method using a reflectometer-type measuring device with an embedded dipole antenna that analyzes reflected radio frequency signals to determine moisture content by identifying resonance frequencies, allowing for precise core measurements without destruction or specialized qualifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If destructive measurement techniques are used to accurately determine moisture content in concrete or mortar, then measurement precision is improved, but the material is damaged requiring sample taking and reducing productivity

Engineering Contradiction:

Improvemoisture content measurement accuracyVSAvoidconstruction progress

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces destructive mechanical sampling methods with a non-destructive electromagnetic measurement system. A probe emitting electromagnetic waves (radar technology) measures moisture content through the material without physical destruction, allowing continuous monitoring and eliminating the need to take core samples that would damage the structure and delay construction.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If non-destructive measurement techniques are used to estimate moisture content, then productivity is improved by avoiding material damage, but measurement precision deteriorates due to surface-only measurements

Engineering Contradiction:

Improveconstruction efficiencyVSAvoidcore moisture level accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent transitions from surface-level moisture measurement to deep interior measurement by utilizing electromagnetic wave penetration in the radio frequency range. The probe emits waves that penetrate deep into the concrete or mortar, allowing measurement of core moisture levels rather than just surface conditions, thereby achieving both non-destructiveness and high measurement precision.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of operation

If existing non-destructive techniques are used, then ease of operation is improved, but measurement precision deteriorates due to chemical reactions and percolation changes

Engineering Contradiction:

Improvemeasurement simplicityVSAvoidhumidity level accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the operating frequency parameter to the radio frequency range (1 MHz to 10 GHz), which fundamentally alters how the measurement is performed. At these frequencies, electromagnetic waves penetrate the material without causing chemical reactions or percolation changes that affect accuracy at lower frequencies, thereby maintaining both ease of operation and high measurement precision.

Inventive Principle:

Principle #35Parameter changes

4Reliability

If safety margins are applied to drying times due to measurement uncertainties, then reliability is improved by ensuring adequate drying, but loss of time increases due to prolonged construction schedules

Engineering Contradiction:

Improvedrying adequacyVSAvoidconstruction duration

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements continuous or periodic monitoring of core moisture levels using the radar probe, providing real-time feedback on drying progress. This allows construction schedules to be optimized based on actual moisture content data rather than relying on conservative safety margins, ensuring adequate drying while minimizing unnecessary delays and reducing overall construction time.

Inventive Principle:

Principle #23Feedback

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

Enables quick, accurate, and cost-effective monitoring of moisture content in materials like concrete and mortar, optimizing construction schedules by ensuring adherence to moisture thresholds without destructive sampling or complex equipment.

Implementation Method 1

analyzes reflected radio frequency signals to determine moisture content by identifying resonance frequencies

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 2

emits a radio frequency signal into the material through the antenna; receive a signal reflected by the antenna

Methodology Applied

Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentEP3268735B1Non-destructive measurement of the degree of humidity of a material

Publication Date: 2025.11.12 ECOLE SUPERIEURE DE PHYSIQUE & DE CHIMIEINDUSTRIELLES DE LA VILLE DE PARIS

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Figure 3a~3d

AI summary

The present invention relates to a method of non-destructive measurement of a degree of humidity of a material (B), such as for example a mortar or a concrete in the course of drying, the method comprising: a step of emitting (S1) a radiofrequency signal (S_RF) in the material (B) through an antenna (10a, 10a') embedded in the material, a step of receiving (S2) a reflected signal (SR) in response to the radiofrequency signal emitted (S_RF), a step (S3) of frequency analysis of the reflected signal so as to determine resonant frequencies of the antenna (10a, 10a') in the material (B), and a step of estimating the degree of humidity of the material (B) on the basis of the resonant frequencies determined.