Compacted material density measurement and compaction tracking system

• US 6,122,601 A
• Filed: 02/20/1998
• Issued: 09/19/2000
• Est. Priority Date: 03/29/1996
• Status: Expired due to Term

• Current Assignee: Penn State Research Foundation (Pennsylvania State University)
• Original Assignee: Penn State Research Foundation (Pennsylvania State University)
• Inventors: Thomas, H. Randolph, Oloufa, Amr A., Swanson, David C.
• Primary Examiner(s): Hoff, Marc S.
• Assistant Examiner(s): MILLER, CRAIG S
• Application Number:
  US09/027,233
• Time in Patent Office: 942 Days
• Field of Search: 701/50, 701/200, 701/208, 701/213, 701/300, 172/2, 172/7, 37/348, 340/988, 340/990, 340/995, 364/151, 702/33-56, 702/85, 702/94, 702/95, 702/137-141, 702/150, 702/179-181, 702/191
• US Class Current: 702/137
• CPC Class Codes: A01B 79/005 Precision agriculture
• CPC Class Codes: E01C 19/288 adapted for monitoring characteristics of the material being compacted, e.g. indicating resonant frequency, measuring degree of compaction, by measuring values, detectable on the roller; using detected values to control operation of the roller, e.g. automatic adjustment of vibration responsive to such measurements
• CPC Class Codes: E02D 3/026 by rolling with rollers usable only for or specially adapted for soil compaction, e.g. sheepsfoot rollers rollers for soil working in agriculture A01B29/00; rollers for road paving, such rollers usable also for compacting soil E01C19/23

Abstract

The present invention provides a two component system to obtain uniform density of compacted materials and track the compaction of the materials. The first component provides an automated, real-time compaction density meter and method of use to measure the density of the compacted material. The second component provides a Geographic Information System (GIS) for tracking compaction of a surface at specific locations. The two components of the present invention combined provide a system to measure the density of the compacted material and record the location of each density measurement. The components of the present invention can be utilized for many compaction operations, such as the roller compaction of concrete, pavement, soil, landfills, and asphalt pavements.

Claims

1. A compaction density meter comprising:

an input device which inputs at least one parameter signal representing a characteristic of a surface to be compacted;

a measuring device which generates at least one vibration signal representing a vibratory response produced by vibration during compaction; and

a computer system which determines density of the compacted surface in response to the at least one parameter signal and the at least one vibration.

2. The compaction density meter of claim 1, wherein the characteristic for the parameter signal comprises pavement type, mix type, base types or site condition.

3. The compaction density meter of claim 1, further comprising a geographic information system for tracking a geographical position of the compaction density meter during compaction of the surface.

4. The compaction density meter of claim 3, wherein the surface is selected from the group consisting of pavement, asphalt, roller compacted concrete, earth, earthen embankments, landfills and other compacted surfaces.

5. The compaction density meter of claim 3, wherein the compaction of the surface is tracked on the basis of position and number of coverages.

6. The compaction density meter of claim 3, wherein the geographic information system records the geographical position during compaction.

7. A method of measuring density of a compacted material during compaction, comprising the steps of inputting characteristic parameters of compaction equipment and material to be compacted;

obtaining vibratory response data of the compaction equipment and density measurements of the material to be compacted which are measured during compaction test strips of the material by the compaction equipment; and

determining the density of the compacted material in response to the input characteristic parameters, the vibratory response data, and the density measurements.

8. The method of claim 7, wherein the characteristic parameters include pavement type, mix type, base type, site conditions and various mix design parameters.

9. The method of claim 7, wherein the vibratory response is measured by an accelerometer.

10. The method of claim 7, wherein the density of the material is measured by a nuclear density gauge.

11. The method of claim 7, wherein vibratory response and density measurements are taken several times during compaction of the test strips to provide a useful database.

12. The method of claim 7, further including the step of using a filtering scheme to eliminate possible stray signals from measurement equipment that measures the vibratory response of the compaction equipment.

13. The method of claim 7, further comprising the step of reporting the density of the compacted material and continuing to measure in real time the density of material as the compactor continues compacting.

14. The method of claim 7, further comprising the step of recording each density value calculated and a position of the compacted material where the density value was taken.

15. The method of claim 14, further including the steps of:

a) identifying an initial position of the compactor with respect to the surface;

b) monitoring movement of the compactor over the surface;

c) digitally recording the movement of the compactor over the surface; and

d) calculating the compaction of the surface based upon the initial position of the compactor and its geometric properties and the digitally recorded movement of the compactor over the surface.

16. The method of claim 14, further including the steps of:

a) identifying an initial position of the compactor with respect to the surface;

b) monitoring each movement of the compactor over the surface;

c) creating a polygonal representation corresponding to each said movement of the compactor over the surface;

d) developing a topological overlay which combines each said polygonal representation;

e) identifying each intersection and each union of said polygonal representations within said topical overlay; and

f) calculating the compaction of said various portions of the surface based upon each said intersection and each said union in topological overlay.

17. The method of claim 7, wherein the developed equations are derived using a software package for linear multiple regression modeling.

18. The method of claim 7, wherein the developed equations are entered into a computer which is onboard the compactor and wherein the computer is connected to a device to measure the vibratory response of the compactor during compaction.

19. The method of claim 7, further comprising the step of developing a relationship of a likelihood function to select a final density value from values determined from the developed equations.

20. The method of claim 19, wherein the likelihood function is a technique known as Bayesian statistics.

21. A compactor comprising:

a compaction apparatus for compacting a surface;

an input device which inputs at least one parameter signal representing a characteristic of a surface to be compacted;

a measuring device which generates at least one vibration signal representing a vibratory response produced by vibration during compaction by the compaction apparatus; and

a computer system which determines density of the compacted surface in response to the at least one parameter signal and the at least one vibration signal.

22. The compactor as set forth in claim 21, wherein the characteristic comprises pavement type, mix type, base type, or site condition.

23. The compactor as set forth in claim 21 further comprising a geographic information system for tracking a geographical position of the compaction density meter during compaction of the surface.