Embedded wireless monitoring sensors

• US 10,324,078 B2
• Filed: 03/30/2017
• Issued: 06/18/2019
• Est. Priority Date: 03/30/2016
• Status: Active Grant

• Current Assignee: Giatec Scientific, Inc.
• Original Assignee: Giatec Scientific, Inc.
• Inventors: Ghods, Pouria, Alizadeh, Rouhollah, Salehi, Mustafa, De Carufel, Sarah
• Primary Examiner(s): Marini, Matthew G
• Application Number:
  US15/474,175
• Publication Number:
  US 20170284996A1
• Time in Patent Office: 810 Days
• Field of Search: None
• CPC Class Codes: B28B 23/0031 with product identification means, e.g. labels on test products or integrated circuit tags inside products RFID
• CPC Class Codes: B28C 7/02 Controlling the operation of the mixing
• CPC Class Codes: C04B 40/0096 Provisions for indicating condition of the compositions or the final products, e.g. degree of homogeneous mixing, degree of wear
• CPC Class Codes: G01N 17/04 Corrosion probes
• CPC Class Codes: G01N 2203/0092 Visco-elasticity, solidification, curing, cross-linking degree, vulcanisation or strength properties of semi-solid materials
• CPC Class Codes: G01N 27/048 for determining moisture content of the material
• CPC Class Codes: G01N 33/383 Concrete, cement

Abstract

Concrete can be one of the most durable building materials where consumption is projected to reach approximately 40 billion tons in 2017 alone. Despite this the testing of concrete at all stages of its life cycle is still in its infancy although testing for corrosion is well established. Further many of the tests today are time consuming, expensive, and provide results only after it has been poured and set. Accordingly, by exploiting self-contained wireless sensor devices, which are deployed with the wet concrete, the in-situ curing and maturity measurement data can be established and employed together with batch specific concrete data to provide rapid initial tests and evolving performance data regarding the concrete cure, performance, corrosion of concrete at different points in its life cycle. Such sensors remove subjectivity, allow for rapid assessment, are integrable to the construction process, and provided full life cycle assessment.

Claims

1. A method comprising:

providing a self-contained sensor device comprising a microprocessor, a battery, a memory in communication with the microprocessor, and a temperature sensor in communication with the microprocessor;

storing calibration data within the memory of the self-contained sensor device relating to properties of a first material within which the self-contained sensor device is to be disposed;

shipping the self-contained sensor device with either a second material for use in forming a mixture of the first material or the mixture of the first material; and

deploying the self-contained sensor device in association with the mixture of the first material;

wherein

the microprocessor of the self-contained sensor device is configured to automatically execute a process comprising;

performing a plurality of measurements upon the mixture of the first material with a subset of the one or more sensors within the self-contained sensor at a plurality of points in time; and

determining based upon at least the plurality of measurements obtained by the self-contained sensor device and a first subset of the calibration data a first characteristic of the mixture of the first material, wherein the plurality of measurements are temperatures of the mixture of the first material and the first characteristic of the mixture of the first material is its compressive strength (S);

wherein determining the characteristic of the mixture of the first material comprises;

determining a maturity index (M) of the mixture of the first material in dependence upon at least the plurality of measurements of temperature of the first material; and

substituting the determined maturity index (M) into S=a+b·

log (M) to derive a prediction of the compressive strength (S) of the mixture of the first material; and

the self-contained sensor device further contains;

a wireless transceiver operating according to a predetermined standard coupled to the microprocessor; and

at least one pressure sensor coupled to the microprocessor allowing the depth at which the self-contained sensor device is deployed within the mixture of the first material to be calculated;

at least one vibratory element coupled to the microprocessor;

wherein

in a first configuration the vibratory element is activated by the microprocessor when the determined depth of the self-contained sensor device differs from a target depth in order to adjust the depth of the self-contained sensor device; and

in a second configuration the vibratory element is activated by the microprocessor when the microprocessor determines that no wireless signal is being received by the wireless transceiver such that the depth of the self-contained sensor device is adjusted until wireless reception is established.

2. The method according to claim 1, wherein

shipping the self-contained sensor device comprises one of:

shipping the self-contained sensor device within a package of the second material used to form the first material, wherein the second material is selected from the group comprising cement, mortar, an admixture for concrete, an aggregate, a slurry or paste employed in forming the first material which is a non-cementitious construction material;

shipping the self-contained sensor device as part of a package of the second material for addition to the first material as it is mixed, wherein the second material is selected from the group comprising cement, mortar, an admixture for concrete, an aggregate, a slurry or paste employed in forming the first material which is a cementitious construction material, and a non-cementitious product employed in infrastructure construction; and

shipping the self-contained sensor device in response to an order for the second material, wherein the second material is selected from the group comprising cement, mortar, an admixture for concrete, an aggregate, a slurry or paste employed in forming a cementitious construction material, and a non-cementitious product employed in infrastructure construction.

3. The method according to claim 1, wherein

shipping the self-contained sensor device comprises one of:

shipping the self-contained sensor as part of a bag filled with the mixture of the first material which is one of a cement, a mortar mix and a concrete mix where the bag is designed to be laid down and absorb water through at least one of a natural process and being watered; and

shipping the self-contained sensor as part of a material formed from the first material wherein the self-contained sensor monitors the manufacture, storage and deployment of the material.

4. The method according to claim 1, further comprising

establishing in dependence upon the measurement data and material data relating to the first mixture construction data relating to at least one of structural stability, a durability property, and a service life estimation of at least one of an element or structure formed from the first material.

5. The method according to claim 1, wherein

the self-contained sensor device further comprises a sensor for performing an electrical impedance measurement;

and

the self-contained sensor device is further configured to;

perform a plurality of measurements upon the mixture of the first material with the sensor within the self-contained sensor at a plurality of points in time; and

determine based upon at least the plurality of measurements obtained by the self-contained sensor device from the sensor and a second subset of the calibration data a second characteristic of the mixture of the first material, wherein

each electrical impedance measurement is adjusted in dependence upon at least one of;

a temperature at the time of the electrical impedance measurement, the adjustment comprising a predetermined activation energy selected from a plurality of activation energies in dependence upon the second characteristic, each activation energy of the plurality of activation energies associated with a different characteristic of the mixture of the first material; and

a correction factor applied for a variation of resistivity of the first material with at least one of saturation and water to concrete ratio.

6. The method according to claim 1, wherein

the self-contained sensor device is activated from a low power mode to perform measurements based upon the self-contained sensor device by either determining that externally applied pressure to the self-contained sensor device has exceeded a predetermined threshold or determining that an impedance measurement indicates the presence of a low conductivity material between a pair of electrical contacts at least one of exterior to or upon the casing of the self-contained sensor device.

7. The method according to claim 1, wherein

shipping the self-contained sensor device for use in association with the mixture of the first material is selected from the group comprising:

mounting the self-contained sensor device to a rebar;

embedding the self-contained sensor device within a formwork panel forming part of a framework within which the mixture of the first material is poured;

mounting the self-contained sensor device upon a formwork panel forming part of a framework onto which or into which the mixture of the first material is poured; and

employing the self-contained sensor device in conjunction with a formwork panel such that the self-contained sensor device is in contact with the mixture of the first material, monitors the temperature of the mixture of the first material at one or more points, monitors the ambient temperature, and provides an indication upon determining that a strength of the mixture of the first material has reached a certain level, wherein the indication is selected from the group comprising a visual indication and a vibration.

8. The method according to claim 1, wherein

the coefficients a and b comprise a predetermined portion of the data stored within self-contained sensor device and are established by a process comprising:

establishing a plurality of measurements of temperature of the first material at a plurality of points in time;

determining a maturity index (M) of the first material in dependence upon at least the plurality of measurement of the temperature of the first material;

establishing the electrical resistivity (ρ

) of the first material at a plurality of specific times;

establishing an initial electrical resistivity (ρ

_s) at an inflection point in a curve of the electrical resistivity (ρ

) versus time;

establishing the electrical resistivity (ρ

_t) of the first material at a specific time (t);

measuring the compressive strength (S_t) of the first material at the specific time (t);

solving

9. The method according to claim 1, wherein

the mixture of the first material is wet concrete;

and

the self-contained sensor device contains at least one of;

one or more pressure sensors allowing the depth at which the self-contained sensor device is deployed within the mixture of the first material to be calculated in dependence upon a hydraulic pressure of the mixture of the first material;

a plurality of temperature sensors disposed at different points allowing a temperature gradient within the mixture of the first material to be established; and

a plurality of humidity sensors disposed at different points allowing a humidity gradient within the mixture of the first material to be established.

10. A construction material system comprising:

a first predetermined portion of the construction material system comprising a first predetermined portion of a first material; and

a second predetermined portion of the construction material system comprising at least one self-contained sensor device of a plurality of self-contained sensor devices and a second material comprising a second predetermined portion of the first material;

wherein

the first predetermined portion of the construction material system and the second predetermined portion of the construction material system are intended to be shipped to a predetermined location for deployment as part of a construction project;

each self-contained sensor device is configured to automatically execute a process comprising performing a plurality of measurements at a plurality of points in time upon the first material and to determine based upon the plurality of measurements and calibration data stored within the self-contained sensor device a characteristic of the first material;

the plurality of measurements are temperatures of the first material and the characteristic of the first material is its compressive strength (S);

the self-contained sensor is configured to determine the characteristic of the first material comprises;

determining a maturity index (M) of the first material in dependence upon at least the plurality of measurements of temperature of the first material; and

substituting the determined maturity index (M) into S=a+b·

log (M) to derive a prediction of the compressive strength (S) of the first material; and

each self-contained sensor device of the plurality of self-contained sensor devices further contains;

a microprocessor;

a wireless transceiver operating according to a predetermined standard coupled to the microprocessor; and

at least one pressure sensor coupled to the microprocessor allowing the depth at which the self-contained sensor device is deployed within the mixture of the first material to be calculated;

at least one vibratory element coupled to the microprocessor;

wherein

in a first configuration the vibratory element is activated by the microprocessor when the determined depth of the self-contained sensor device differs from a target depth in order to adjust the depth of the self-contained sensor device; and

in a second configuration the vibratory element is activated by the microprocessor when the microprocessor determines that no wireless signal is being received by the wireless transceiver such that the depth of the self-contained sensor device is adjusted until wireless reception is established.

11. The construction material system according to claim 10, wherein

the second predetermined portion of the construction material system is shipped as one of:

the self-contained sensor device within a package of the second material for addition to the first predetermined portion of the construction material, wherein the second material is selected from the group comprising cement, mortar, an admixture for concrete, an aggregate, a slurry or paste employed in forming a non-cementitious construction material;

the self-contained sensor device as part of a package of the second material for addition to the first predetermined portion of the construction material, wherein the second material is selected from the group comprising cement, mortar, an admixture for concrete, an aggregate, a slurry or paste employed in forming a non-cementious construction material, and a non-cementitious product employed in infrastructure construction; and

the self-contained sensor device and second material separately in response to an order for the second material, wherein the second material is selected from the group comprising cement, mortar, an admixture for concrete, an aggregate, a slurry or paste employed in forming a non-cementitious construction material, and a non-cementitious product employed in construction.

12. The construction material system according to claim 10, wherein

the second predetermined portion of the construction material system is shipped as one of:

part of a bag filled with the second material designed to be laid down and absorb water through at least one of a natural process and being watered, wherein the second material is a cement or a mortar mix; and

part of a bag filled with the second material and first predetermined portion of the first material designed to be laid down and absorb water through at least one of a natural process and being watered, wherein the first material is a concrete mix.

13. The construction material system according to claim 10, further comprising

an electronic device comprising at least a microprocessor and a wireless transceiver operating according to a predetermined wireless protocol, wherein the electronic device is configured to:

wirelessly communicate with one or more sensors to retrieve measurement data from the one or more sensors when embedded within the first material; and

establish in dependence upon the retrieved measurement data and material data relating to the first mixture construction data relating to at least one of structural stability, a durability property, and a service life estimation of at least one of an element or structure formed from the first material.

14. The construction material system according to claim 10, wherein

the self-contained sensor device further comprises a sensor for performing an electrical impedance measurement;

and

the self-contained sensor device is further configured to;

perform a plurality of electrical impedance measurements upon the mixture of the first material with the sensor within the self-contained sensor at a plurality of points in time; and

determine based upon at least the plurality of electrical impedance measurements obtained by the self-contained sensor device from the sensor and further calibration data stored within the self-contained sensor device a second characteristic of the mixture of the first material, wherein

each electrical impedance measurement is adjusted in dependence upon at least one of;

a temperature at the time of the electrical impedance measurement, the adjustment comprising a predetermined activation energy selected from a plurality of activation energies in dependence upon the second characteristic, each activation energy of the plurality of activation energies associated with a different characteristic of the mixture of the first material; and

a correction factor relating to a variation of resistivity of the first material with at least one of saturation and water to concrete ratio.

15. The construction material system according to claim 10, wherein

the self-contained sensor device is activated to perform measurements based upon the self-contained sensor device either determining that externally applied pressure to the self-contained sensor device has exceeded a predetermined threshold or determining that an impedance measurement indicates the presence of a low conductivity material between a pair of electrical contacts at least one of exterior to or upon the casing of the self-contained sensor device.

16. The construction material system according to claim 10, wherein

the coefficients a and b comprise a predetermined portion of the data stored within the self-contained sensor device and are established by a process comprising:

establishing a plurality of measurements of temperature of the first material at a plurality of points in time;

determining a maturity index (M) of the first material in dependence upon at least the plurality of measurement of the temperature of the first material;

establishing the electrical resistivity (ρ

) of the first material at a plurality of specific times;

establishing an initial electrical resistivity (ρ

_s) at an inflection point in a curve of the electrical resistivity (ρ

) versus time;

establishing the electrical resistivity (ρ

_t) of the first material at a specific time (t);

measuring the compressive strength (S_t) of the first material at the specific time (t);

solving

17. The construction material system according to claim 10, wherein

the mixture of the first material is concrete;

and

the self-contained sensor device contains at least one of;

one or more pressure sensors allowing the depth at which the self-contained sensor device is deployed within the mixture of the first material to be calculated in dependence upon a hydraulic pressure of the mixture of the first material;

a plurality of temperature sensors disposed at different points allowing a temperature gradient within the mixture of the first material to be established; and

a plurality of humidity sensors disposed at different points allowing a humidity gradient within the mixture of the first material to be established.

18. A method of establishing maturity data relating to a material being cured comprising:

providing a plurality of sensor devices, each sensor device comprising;

a microprocessor;

a battery;

a memory in communication with the microprocessor;

a plurality of sensors in communication with the microprocessor of which at least one is a pressure sensor allowing the depth at which the self-contained sensor device is deployed within the mixture of the first material to be calculated;

a wireless transceiver operating according to a predetermined standard coupled to the microprocessor;

at least one vibratory element coupled to the microprocessor;

wherein

in a first configuration the vibratory element is activated by the microprocessor when the determined depth of the self-contained sensor device differs from a target depth in order to adjust the depth of the self-contained sensor device; and

in a second configuration the vibratory element is activated by the microprocessor when the microprocessor determines that no wireless signal is being received by the wireless transceiver such that the depth of the self-contained sensor device is adjusted until wireless reception is established;

wirelessly transmitting to an electronic device a prediction of the mature compressive strength M of the material from each sensor device of the plurality of sensor devices;

wherein

the prediction of the mature compressive strength M of the material is established and wirelessly transmitted whilst the material in contact with the plurality of sensor devices is curing and has a high moisture content; and

the microprocessor within each sensor device of the plurality of sensor devices is configured to establish the prediction of the mature compressive strength M of the material by executing a process comprising the steps of;

establishing the electrical resistivity (ρ

_t) of the material at a plurality of specific times (t);

establishing the in-situ compressive strength (S_t) of the material at the plurality of specific times;

deriving mix dependent coefficients c and d using S_t=c+d·

log(ρ

_t);

substituting c and d into