Chemo-thermo-piezoresistive highly sensing smart cement with integrated real-time monitoring system

1. A system for monitoring performance-related properties of cement, comprising:

a cement structure comprised of chemo-thermo-piezoresistive smart cement, wherein the chemo-thermo-piezoresistive smart cement comprises from about 0.03% to about 0.1% modified conductive or semi-conductive filler by weight of the chemo-thermo-piezoresistive smart cement, and wherein the modified conductive or semi-conductive filler comprises dispersed carbon fibers, dispersed basaltic fibers, or mixtures thereof; and

an integrated real-time monitoring system for monitoring changes in electrical resistivity of the chemo-thermo-piezoresistive smart cement, wherein the changes in the electrical resistivity of the chemo-thermo-piezoresistive smart cement correlate with performance-related properties of the chemo-thermo-piezoresistive smart cement, wherein the integrated real-time monitoring system collects AC resistance measurements at selected frequencies, wherein the integrated real-time monitoring system uses the AC resistance measurements to calculate the changes in the electrical resistivity and changes in electrical impedance of the chemo-thermo-piezoresistive smart cement using an equivalent circuit to represent electrical properties of the chemo-thermo-piezoresistive smart cement, wherein the chemo-thermo-piezoresistive smart cement is represented in the equivalent circuit as a bulk material with contacts as follows:

Z

2

⁡

(

σ

)

=

R

b

⁡

(

σ

)

+

2

⁢

⁢

R

c

⁡

(

σ

)

1

+

ω

2

⁢

R

c

2

⁢

C

c

2

-

j

⁢

⁢

2

⁢

⁢

ω

⁢

⁢

R

c

2

⁢

C

c

⁡

(

σ

)

1

+

ω

2

⁢

R

c

2

⁢

C

c

2

,

wherein Z 2 is total electrical impedance for the equivalent circuit, R b is resistance of the bulk material, R c is resistance of the contacts, C c is capacitance of the contacts, and ω is a selected frequency, and wherein the equivalent circuit assumes a negligible capacitance for the bulk material.

2. The system of claim 1 , wherein the performance-related properties of the smart cement comprise curing, compressive strength, induced stresses, water-to-cement ratio, temperature changes, fluid loss, and contamination of the chemo-thermo-piezoresistive smart cement.

3. The system of claim 1 , wherein the changes in the electrical resistivity of the chemo-thermo-piezoresistive smart cement correlate with performance-related properties of the cement with and without contamination.

4. The system of claim 1 , wherein the cement structure is part of an oil or gas well.

5. The system of claim 1 , wherein the cement structure is part of civil infrastructures selected from the group consisting of footings, piles, pipelines, buildings, tunnels, bridges, and highways.

6. The system of claim 1 , wherein the chemo-thermo-piezoresistive smart cement is part of grout, concrete, a coating, or a repair material.

7. A method for real-time monitoring of performance-related properties of cement, comprising:

constructing a cement structure, wherein the cement structure comprises chemo-thermo-piezoresistive smart cement and an integrated real-time monitoring system for monitoring changes in electrical resistivity of the chemo-thermo-piezoresistive smart cement, wherein the chemo-thermo-piezoresistive smart cement comprises from about 0.03% to about 0.1% modified conductive or semi-conductive filler by weight of the chemo-thermo-piezoresistive smart cement, and wherein the modified conductive or semi-conductive filler comprises dispersed carbon fibers, dispersed basaltic fibers, or mixtures thereof;

collecting AC resistance measurements of the chemo-thermo-piezoresistive smart cement at selected frequencies using the integrated real-time monitoring system;

using the AC resistance measurements to calculate changes in the electrical resistivity of the chemo-thermo-piezoresistive smart cement and changes in electrical impedance of the chemo-thermo-piezoresistive smart cement using an equivalent circuit to represent electrical properties of the chemo-thermo-piezoresistive smart cement, wherein the chemo-thermo-piezoresistive smart cement is represented in the equivalent circuit as a bulk material with contacts as follows:

Z

2

⁡

(

σ

)

=

R

b

⁡

(

σ

)

+

2

⁢

⁢

R

c

⁡

(

σ

)

1

+

ω

2

⁢

R

c

2

⁢

C

c

2

-

j

⁢

⁢

2

⁢

⁢

ω

⁢

⁢

R

c

2

⁢

C

c

⁡

(

σ

)

1

+

ω

2

⁢

R

c

2

⁢

C

c

2

,

wherein Z 2 is total electrical impedance for the equivalent circuit, R b is resistance of the bulk material, R c is resistance of the contacts, C c is capacitance of the contacts, and ω is a selected frequency, and wherein the equivalent circuit assumes a negligible capacitance for the bulk material; and

monitoring the changes in the electrical resistivity and the electrical impedance of the chemo-thermo-piezoresistive smart cement using the integrated real-time monitoring system, wherein the changes in the electrical resistivity of the chemo-thermo-piezoresistive smart cement correlate with performance-related properties of the chemo-thermo-piezoresistive smart cement.

8. The method of claim 7 , wherein the changes in the electrical resistivity of the chemo-thermo-piezoresistive smart cement correlate with performance-related properties of the cement with and without contamination.

9. The method of claim 7 , wherein the performance-related properties of the cement comprise curing, compressive strength, induced stresses, water-to-cement ratio, temperature changes, fluid loss, and contamination of the chemo-thermo-piezoresistive smart cement.

10. The method of claim 7 , wherein the cement structure is part of an oil or gas well.

11. The method of claim 7 , wherein the cement structure is part of civil infrastructures selected from the group consisting of footings, piles, pipelines, buildings, tunnels, bridges, and highways.

12. The method of claim 7 , wherein the chemo-thermo-piezoresistive smart cement is part of grout, concrete, a coating, or a repair material.