Slump Flow Monitoring

• US 20120016523A1
• Filed: 08/07/2009
• Published: 01/19/2012
• Est. Priority Date: 03/27/2009
• Status: Active Grant

• Current Assignee: Verifi, LLC (Compagnie De Saint-Gobain)
• Original Assignee: Verifi, LLC (Compagnie De Saint-Gobain)
• Inventors: Verdino, Steve, Koehler, Eric, Klauke, James, Culley, Robert, Sostaric, Joseph
• Granted Patent: US 8,818,561 B2
• Time in Patent Office: Days
• US Class Current: 700/265
• CPC Class Codes: B28C 7/026 by measuring data of the driving system, e.g. rotational speed, torque, consumed power
• CPC Class Codes: G01N 11/00 Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties
• CPC Class Codes: G01N 2011/0046 In situ measurement during mixing process
• CPC Class Codes: G01N 2011/0053 using ergometry; measuring power consumption
• CPC Class Codes: G01N 33/383 Concrete, cement

Abstract

Method and system for monitoring slump flow of hydratable cementitious material such as wet concrete in a rotating mixing drum. Whereas prior art methods use a single value of the hydraulic pressure for turning the drum (such as the average value) and correlating with slump values using the vertical drop measurements of the standard slump test (e.g. ASTM C 143-05), the present invention involves analysis of values corresponding to slump flow of concrete samples, preferably having slump flow values of 16-36 inches when measured using standard slump flow tests (e.g., ASTM C1611-05).

Claims

1. A method for monitoring a cementitious material, comprising:

(A) rotating a mixing drum containing a hydratable cementitious material therein;

(B) providing a sequence of values corresponding to hydraulic pressure required to rotate said mixing drum at a particular speed V¹ and calculating an average value based on said sequence of values;

(C) comparing said calculated average value to a set of average values at speed V¹ previously stored in computer memory storage location, said previously stored set containing values obtained from hydratable cementitious materials having predetermined slump flows at various slump flows within the range of 16 inches to 36 inches determined by measuring horizontal spread of cementitious material released from a slump cone; and

(D) providing an indication of slump flow corresponding to said calculated average value provided in (B);

adjusting the slump flow of said hydratable cementitious material in said mixing drum based on comparing said calculated average value to a set of average values previously stored in computer memory storage location;

or performing a combination thereof.

2. The method of claim 1 wherein, in providing an indication of slump flow corresponding to said calculated average value, said indication is provided by computer monitor display, printed paper output, or entry of data into computer memory storage location.

3. The method of claim 1 further comprising adjusting the slump flow of said hydratable cementitious material in said mixing drum based on comparing said calculated average value to a set of average values previously stored in computer memory storage location, by introducing a liquid into said hydratable cementitious material.

4. The method of claim 1 wherein said liquid comprises water, a chemical admixture, or a combination thereof.

5. The method of claim 1 further comprising providing values corresponding to the tilt or inclination of the mixing drum, the concrete load size, the temperature of the concrete, or some combination thereof.

6. The method of claim 5 further comprising adjusting the amount of said liquid based on said value corresponding to the tilt or inclination of the mixing drum, the concrete load size, the temperature of the concrete, or some combination thereof.

7. The method of claim 1 wherein, in rotating a mixing drum containing a hydratable cementitious material therein, the water content of said hydratable cementitious material is adjusted to achieve a predetermined slump within the range of 0 to 10 inches, and subsequently chemical cement dispersant is introduced to adjust the slump flow of said hydratable cementitious material to a pre-determined slump flow within the range of 16 to 36 inches.

8. The method of claim 1 wherein, in rotating a mixing drum containing a hydratable cementitious material therein, water is introduced to adjust the slump flow of said hydratable cementitious material to a pre-determined slump flow within the range of 16 to 36 inches, and subsequent maintenance of the slump flow with time is achieved by adjusting cement dispersant quantity.

10. The method of claim 1 wherein the hydraulic pressure used to determine slump flow is calculated as a function of the hydraulic pressures measured on both the charge and discharge ports of the hydraulic system.

11. The method of claim 1 wherein, in comparing said calculated average value to a set of average values at speed V¹ previously stored in computer memory storage location, different calibration curves are used for different mixture designs.

12. The method of claim 1 wherein, the average value of hydraulic pressure required to rotate said mixing drum at a particular speed V¹ is calculated after the average hydraulic pressure is constant over time, indicating the concrete and any added water or cement dispersant are fully mixed.

13. The method of claim 7 wherein the initial predetermined slump is adjusted based on the concrete temperature.

14. The method of claim 7 wherein a second predetermined slump is used instead of a predetermined slump flow, with the second predetermined slump being greater than the first predetermined slump.

15. The method of claim 1 wherein said mixing drum has an inner surface upon which at least one mixing blade is attached to said inner surface such that said at least one mixing blade rotates with said mixing drum.

9. A system for monitoring slump flow, comprising:

a rotatable mixing drum for mixing a hydratable cementitious material, a sensor for measuring hydraulic pressure required for rotating said mixing drum, a sensor for measuring rotational speed of said mixing drum, a computer processing unit for receiving values from said sensor for measuring hydraulic pressure required for rotating said mixing drum and for receiving values from said sensor for measuring rotational speed of said mixing drum, and computer memory storage location having stored therein a set of values obtained from hydratable cementitious materials having predetermined slump flows at various slump flows within the range of 16 inches to 36 inches determined by employing manual measurement of horizontal spread of cementitious materials released from an inverted and removed slump cone (e.g., in accordance with a standard cone test such as ASTM C1611-05).

16. A method for monitoring a cementitious material, comprising:

(A) operating a central mixing apparatus located in a stationary concrete mixing plant and containing a hydratable cementitious material therein;

(B) providing a sequence of values corresponding to amperage required to operate the mixing apparatus or mixing blades/fins within the mixing apparatus at a particular speed V¹ and calculating an average value based on said sequence of values;

(C) comparing said calculated average value to a set of average values at speed V¹ previously stored in computer memory storage location, said previously stored set containing values obtained from hydratable cementitious materials having predetermined slump flows at various slump flows within the range of 16 inches to 36 inches determined by measuring horizontal spread of cementitious material released from a slump cone; and

(D) providing an indication of slump flow corresponding to said calculated average value provided in (B);

adjusting the slump flow of said hydratable cementitious material in said mixing apparatus based on comparing said calculated average value to a set of average values previously stored in computer memory storage location;

or performing a combination thereof.

17. The method of claim 16 wherein, in providing an indication of slump flow corresponding to said calculated average value, said indication is provided by computer monitor display, printed paper output, or entry of data into computer memory storage location.

18. The method of claim 16 further comprising adjusting the slump flow of said hydratable cementitious material in said mixing apparatus based on comparing said calculated average value to a set of average values previously stored in computer memory storage location, by introducing a liquid into said hydratable cementitious material.

19. The method of claim 16 wherein said liquid comprises water, a chemical admixture, or a combination thereof.

20. The method of claim 16 further comprising providing values corresponding to the tilt or inclination of the mixing apparatus, the concrete load size, the temperature of the concrete, or combination thereof.

21. The method of claim 16 further comprising adjusting the amount of said liquid based on said value corresponding to the tilt or inclination of the mixing apparatus, the concrete load size, the temperature of the concrete, or some combination thereof.

22. The method of claim 16 wherein, in said mixing apparatus containing a hydratable cementitious material therein, the water content of said hydratable cementitious material is adjusted to achieve a predetermined slump within the range of 0 to 10 inches, and subsequently chemical cement dispersant is introduced to adjust the slump flow of said hydratable cementitious material to a pre-determined slump flow within the range of 16 to 36 inches.

23. The method of claim 16 wherein, in said mixing apparatus containing a hydratable cementitious material therein, water is introduced to adjust the slump flow of said hydratable cementitious material to a pre-determined slump flow within the range of 16 to 36 inches, and subsequent maintenance of the slump flow with time is achieved by adjusting cement dispersant quantity.

25. The method of claim 16 wherein, in comparing said calculated average value to a set of average values at speed V¹ previously stored in computer memory storage location, different calibration curves are used for different mixture designs.

26. The method of claim 16 wherein, the average value of amperage required to operate said mixing apparatus at a particular speed V¹ is calculated after the average amperage is constant over time, indicating the concrete and any added water or cement dispersant are fully mixed.

27. The method of claim 21 wherein the initial predetermined slump is adjusted based on the concrete temperature.

28. The method of claim 21 wherein a second predetermined slump is used instead of a predetermined slump flow, with the second predetermined slump being greater than the first predetermined slump.

24. A system for monitoring slump flow, comprising:

a stationary plant with a central mixing apparatus for mixing a hydratable cementitious material, a sensor for measuring amperage required for rotating the mixing apparatus ors mixing blades/fins within the mixing apparatus, a sensor for measuring rotational speed of said mixing apparatus, a computer processing unit for receiving values from said sensor for measuring amperage required to operate said mixing apparatus and for receiving values from said sensor for measuring rotational speed of said mixing apparatus, and computer memory storage location having stored therein a set of values obtained from hydratable cementitious materials having predetermined slump flows at various slump flows within the range of 16 inches to 36 inches determined by employing manual measurement of horizontal spread of cementitious materials released from an inverted and removed slump cone (e.g., in accordance with a standard cone test such as ASTM C1611-05).