Utilization of heavy oil fly ash to produce controlled low strength material for backfilling applications

Patent metadata

Field	Value
Publication number	US-11434168-B2
Application number	US-202016815805-A
Country	US
Kind code	B2
Filing date	Mar 11, 2020
Priority date	Mar 11, 2019
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

A controlled low strength material has constituents that include a cement, an aggregate, a heavy oil fly ash, and a water. The controlled low strength material has a compressive strength in a range of 300 kPa to 2.1 MPa. In certain embodiments, the heavy oil fly ash can be part of a heavy oil fly ash slurry.

First claim

What is claimed is:

1. A controlled low strength material, constituents of the controlled low strength material including:
a cement in an amount of 2 wt % to 5 wt % of the constituents of the controlled low strength material;
an aggregate in an amount of 75 wt % to 95 wt % of the constituents of the controlled low strength material;
a heavy oil fly ash in an amount of 10 wt % to 50 wt % of the cement; and
a water in an amount of 10 wt % to 15 wt % of the constituents of the controlled low strength material, each based on a weight of the controlled low strength material; where

the controlled low strength material has a compressive strength that does not exceed 2.1 MPa, measured at 28 days.

2. The controlled low strength material of claim 1 , where the heavy oil fly ash includes carbon in an amount of 90 wt % to 95 wt % based on a weight of heavy oil fly ash.

3. The controlled low strength material of claim 1 , where at least 80% of the heavy oil fly ash has a particle size smaller than 45 micrometers.

4. The controlled low strength material of claim 1 , where an amount of aggregate with a particle size greater than 9.5 mm is 10% or less of the amount of aggregate.

5. The controlled low strength material of claim 1 , where the aggregate consists essentially of a natural fine aggregate that has a particle size of less than 4.75 mm and a coarse aggregate.

6. A method for forming a controlled low strength material, the method including:
mixing together constituents that include:
a cement in an amount of 2 wt % to 5 wt % of the constituents of the controlled low strength material;
an aggregate in an amount of 75 wt % to 95 wt % of the constituents of the controlled low strength material;
a heavy oil fly ash in an amount of 10 wt % to 50 wt % of the cement; and
a water in an amount of 10 wt % to 15 wt % of the constituents of the controlled low strength material; where

after mixing, the controlled low strength material has a compressive strength that does not exceed 2.1 MPa, measured at 28 days.

7. The method of claim 6 , where the heavy oil fly ash includes carbon in an amount of 90 wt % to 95 wt % based on a weight of heavy oil fly ash.

8. The method of claim 6 , where at least 80% of the heavy oil fly ash has a particle size smaller than 45 micrometers.

9. The method of claim 6 , where an amount of aggregate with a particle size grater than 9.5 mm is 10% or less of the amount of aggregate.

10. The method of claim 6 , where the aggregate consists essentially of a fine aggregate that has a particle size of less than 4.75 mm, and a coarse aggregate.

11. A method for forming a controlled low strength material, the method including mixing together constituents that include:
a cement;
an aggregate;
a heavy oil fly ash slurry; and
a mixing water; where

the heavy oil fly ash slurry includes a slurry water and a heavy oil fly ash, and where the slurry water and the mixing water together are in an amount of 10 wt % to 20 wt % of the constituents of the controlled low strength material; and
after mixing, the controlled low strength material has a compressive strength that does not exceed 2.1 MPa, measured at 28 days.

12. The method of claim 11 , further including adding the heavy oil fly ash slurry directly to the cement and the aggregate to produce the controlled low strength material.

13. The method of claim 11 , where the heavy oil fly ash includes carbon in an amount of 90 wt % to 95 wt % based on a weight of heavy oil fly ash.

14. The method of claim 11 , where at least 80% of the heavy oil fly ash has a particle size smaller than 45 micrometers.

15. The method of claim 11 , where the amount of aggregate with a particle size greater than 9.5 mm is 10% or less of the amount of aggregate.

16. The method of claim 11 , where the aggregate consists essentially of a fine aggregate that has a particle size of less than 4.75 mm, and a coarse aggregate.

Assignees

• Saudi Arabian Oil Co
• Univ King Fahd Pet & Minerals

Inventors

• Al-Helal Zakariya Saleh
• Acero Carlos Ernesto
• Al-Dulaijan Salah
• Rahman Muhammad Kalimur
• Ibrahim Mohammed

Classifications

• C04B2111/00103

  Self-compacting mixtures · CPC title

• C04B18/087 Primary

  from liquid fuels, e.g. oil · CPC title

• C04B28/04 Primary

  Portland cements · CPC title

• C04B28/02

  containing hydraulic cements other than calcium sulfates · CPC title

• C04B2201/50

  for the mechanical strength · CPC title