# US 10,481,143 B2 · Chemo-thermo-piezoresistive highly sensing smart cement with integrated real-time monitoring system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,481,143 B2 - Document ID: US10481143B2 - Status: Granted - Kind: B2 - Application number: 15/745,558 - Filed: 2016-07-12 - Published: 2018-07-26 - Granted: 2019-11-19 - Earliest claimed: 2015-07-13 - Assignees: University of Houston System - Applicants: University of Houston System - Inventors: Cumaraswamy Vipulanandan - Web page: https://patentgrep.com/patent/US10481143B2 ## CPC - G01N 33/383: {Concrete or cement} - E21B 33/14: for cementing casings into boreholes - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract The chemo-thermo-piezoresistive behavior of so-called “smart cement,” or cement modified with conductive fillers, is useful as a bulk sensor for monitoring the changes in the cement due to stresses, cracks, contamination, fluid loss, and temperature change that affect its performance. The smart cement utilizes a special conductive or semi-conductive filler and is useful as a bulk sensor that allows real-time monitoring of its properties. ## Claims ### Claim 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 Z2 is total electrical impedance for the equivalent circuit, Rb is resistance of the bulk material, Rc is resistance of the contacts, Cc is capacitance of the contacts, and ω is a selected frequency, and wherein the equivalent circuit assumes a negligible capacitance for the bulk material. ### Claim 2 (depends on 1) 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. ### Claim 3 (depends on 1) 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. ### Claim 4 (depends on 1) The system of claim 1, wherein the cement structure is part of an oil or gas well. ### Claim 5 (depends on 1) 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. ### Claim 6 (depends on 1) The system of claim 1, wherein the chemo-thermo-piezoresistive smart cement is part of grout, concrete, a coating, or a repair material. ### Claim 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 Z2 is total electrical impedance for the equivalent circuit, Rb is resistance of the bulk material, Rc is resistance of the contacts, Cc 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. ### Claim 8 (depends on 7) 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. ### Claim 9 (depends on 7) 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. ### Claim 10 (depends on 7) The method of claim 7, wherein the cement structure is part of an oil or gas well. ### Claim 11 (depends on 7) 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. ### Claim 12 (depends on 7) The method of claim 7, wherein the chemo-thermo-piezoresistive smart cement is part of grout, concrete, a coating, or a repair material.