Fibre Optic Sensor for Concrete Hydration Monitoring
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Solution Overview
Problem
Monitoring subsurface concrete structures during hydration is challenging due to their inaccessibility, making it difficult to detect potential failures such as voids, fissures, or non-homogeneous concentrations, which can lead to structural weaknesses and safety issues.
Innovation Solution
A method involving a fibre optic array with at least one fibre optic cable sensor integrated into a reinforcement cage, allowing real-time temperature monitoring during concrete hydration, using an interrogator to collect and analyze temperature data, thereby identifying anomalies before the structure is completed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If subsurface concrete structures are monitored after curing using strain gauges or cross-hole sonic logging, then non-visual assessment is achieved, but potential failures cannot be detected early during construction
Solution Approach 1:
The fibre optic cable sensor is installed within the reinforcement cage before concrete pouring, enabling temperature monitoring to begin during the construction phase. This preliminary placement allows detection of hydration anomalies and potential failures while the structure is still forming, rather than waiting until after curing when traditional methods are used.
Solution Approach 2:
The patent replaces traditional mechanical sensing methods (strain gauges, sonic logging) with an optical sensing system. The fibre optic cable uses optical principles to detect temperature variations during concrete hydration, providing early warning of potential failures without requiring mechanical contact or post-curing access to the subsurface structure.
2Ease of manufacture
If subsurface concrete structures are made inaccessible for monitoring, then construction is simplified, but real-time detection of anomalies becomes difficult
Solution Approach 1:
The fibre optic cable sensor is nested within the reinforcement cage structure, which itself is placed within the subsurface borehole. This nested arrangement allows the sensing element to be positioned exactly where needed (inside the reinforcement cage) without requiring separate installation steps or compromising the simplicity of the overall construction process. The sensor becomes an integrated part of the reinforcement assembly.
Solution Approach 2:
The fibre optic cable sensor autonomously monitors temperature during concrete hydration without requiring external intervention or access to the subsurface structure. The sensor self-generates the monitoring capability by being embedded in the reinforcement cage, eliminating the need for operators to physically access the subsurface location during the critical hydration period.
3Loss of information
If operators are present during concrete placement for monitoring, then real-time data collection is possible, but safety risks and human capital requirements increase
Solution Approach 1:
The patent replaces human operators with an automated fibre optic sensing system that collects temperature data during concrete placement. The fibre optic cable, being non-conductive and chemically inert, can safely remain in the structure during concrete pouring without posing electrical hazards or requiring operator presence, thereby eliminating safety risks while maintaining continuous monitoring capability.
Solution Approach 2:
The fibre optic cable acts as an intermediary between the concrete hydration process and the data collection system. It transmits temperature information from the subsurface location (where operators cannot safely be present) to the surface interrogation system, enabling remote real-time monitoring without exposing humans to hazardous conditions during concrete placement.
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 early detection of potential failures and ensures a uniform concrete structure by providing a mechanism for real-time temperature monitoring, reducing human capital requirements and enhancing safety by minimizing operator presence during construction.
Implementation Method 1
using said at least one fibre optic cable sensor (48) immediately or shortly after the application of concrete medium to directly sense temperature data along a length of the at least one fibre optic cable sensor during hydration of the subsurface concrete structure
Data Source
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AI summary
Fibre optic sensors are used to monitor the integrity of a subsurface concrete structure such as a pile or diaphragm wall. A fibre optic sensor array (48) is attached to a reinforcement or framework assembly (20) for the subsurface concrete structure. Concrete is applied to surround the reinforcement or framework assembly (20) and fibre optic sensor array (48). The fibre optic sensor array (48) is then used to collect temperature data during hydration of the subsurface concrete structure. The temperature data is monitored in real time to determine differentials across the structure, indicative of a problem within the structure.