Electrically-conductive asphalt concrete containing carbon fibers

Patent metadata

Field	Value
Publication number	US-2021024418-A1
Application number	US-202016931179-A
Country	US
Kind code	A1
Filing date	Jul 16, 2020
Priority date	Jul 26, 2019
Publication date	Jan 28, 2021
Grant date	—

Abstract

The present application relates to an electrically conductive asphalt mastic (ECAM) composition that includes an asphalt binder, a mineral filler, and a plurality of conductive carbon microfibers, between 3 and 12 mm in length, which are the sole source of electrical conductivity in the ECAM composition where the conductive carbon microfibers and the mineral filler are dispersed in the asphalt binder, and wherein said conductive carbon microfibers are present in the ECAM composition in an amount of less than 2.00% of total volume of the ECAM composition. The application further relates to an electrically conductive asphalt concrete (ECAC) composition that includes an asphalt binder, a mineral filler, an aggregate, and a plurality of conductive carbon microfibers, where the conductive carbon microfibers are the sole source of electrical conductivity in the electrically conductive asphalt concrete composition.

First claim

What is claimed:

1 . An electrically conductive asphalt mastic (ECAM) composition comprising:
an asphalt binder, a mineral filler, and a plurality of conductive carbon microfibers, between 3 and 12 mm in length, said conductive carbon microfibers being the sole source of electrical conductivity in the ECAM composition, wherein the mineral filler and the conductive carbon microfibers are dispersed in said asphalt binder, and wherein said conductive carbon microfibers are present in the ECAM composition in an amount of less than 2.00% of total volume of the ECAM composition.

2 . The ECAM composition of claim 1 , wherein the mineral filler comprises particles with a diameter of less than 75 microns.

3 . The ECAM composition of claim 1 , wherein the conductive carbon microfibers are selected from the group consisting of polyacrylonitrile (PAN)-based carbon microfibers, pitch-based virgin carbon microfibers, recycled carbon microfibers, and combinations thereof.

4 . The ECAM composition of claim 1 , wherein the asphalt binder is selected from the group consisting of unaged asphalt binder, aged asphalt binder from recycled asphalt pavement, vacuum tower distillation bottom binder, aged asphalt binder from recycled asphalt shingles, de-asphalting bottoms, residuum oil supercritical extraction unit bottoms, and mixtures thereof.

5 . The ECAM composition of claim 1 , wherein the ECAM has a volume resistivity of between 1 Ω.cm and 50 Ω.cm.

6 . An electrically conductive asphalt concrete composition (ECAC) comprising:
an asphalt binder; a mineral filler; an aggregate; and a plurality of conductive carbon microfibers, wherein said conductive carbon microfibers are the sole source of electrical conductivity in the electrically conductive asphalt concrete composition.

7 . The ECAC composition of claim 6 , wherein said conductive carbon microfibers are present in the electrically conductive asphalt concrete composition in an amount of less than 2.00% of total volume of the electrically conductive asphalt concrete composition.

8 . The ECAC composition of claim 6 , wherein the aggregate comprises a coarse aggregate and a fine aggregate.

9 . The ECAC composition of claim 6 , wherein the mineral filler is less than 75 microns in diameter.

10 . The ECAC composition of claim 8 , wherein when the mineral aggregate comprises a fine aggregate having particles with a diameter of between 75 and 4,750 microns.

11 . The ECAC composition of claim 8 , wherein when the mineral aggregate comprises a coarse aggregate having particles with a diameter of between 4,750 and 37,500 microns.

12 . The ECAC composition of claim 8 , wherein the fine aggregate is selected from the group consisting of crushed rocks, sand, and combinations thereof.

13 . The ECAC composition of claim 8 , wherein the coarse aggregate is selected from the group consisting of coarse gravel, limestone, quartzite, granite, recycled geomaterials, and combinations thereof.

14 . The ECAC composition of claim 6 , wherein the conductive carbon microfibers are selected from the group consisting of polyacrylonitrile (PAN)-based carbon microfibers, pitch-based virgin carbon microfibers, recycled carbon microfibers, and combinations thereof.

15 . The ECAC composition of claim 6 , wherein the conductive carbon microfibers are between 3 and 12 mm in length.

16 . The ECAC composition of claim 6 , wherein the asphalt binder is selected from the group consisting of unaged asphalt binder, aged asphalt binder from recycled asphalt pavement, vacuum tower distillation bottom binder, aged asphalt binder from recycled asphalt shingles, de-asphalting bottoms, residuum oil supercritical extraction unit bottoms, and mixtures thereof.

17 . The ECAC composition of claim 6 , wherein the electrically conductive asphalt composition has a void in mineral aggregate value of between 15.0% and 20.0%.

18 . The ECAC composition of claim 6 , wherein the electrically conductive asphalt composition has a void filled with asphalt value of between 60.0% and 80.0%.

19 . The ECAC composition of claim 6 , wherein the electrically conductive asphalt concrete composition comprises less than 10.0 wt % of the asphalt binder.

20 . The ECAC composition of claim 19 , wherein the electrically conductive asphalt concrete composition comprises between 4.0 wt % and 8.0 wt % of the asphalt binder.

21 . The ECAC composition of claim 6 , wherein the electrically conductive asphalt concrete composition has a volume resistivity of between about 15 Ω.cm and about 50 Ω.cm.

22 . The ECAC composition of claim 6 , wherein the mineral aggregate is uniformly distributed throughout the electrically conductive asphalt concrete composition.

23 . A method of producing an electrically conductive asphalt concrete composition comprising:
providing the electrically conductive asphalt concrete composition of claim 6 ; applying the electrically conductive asphalt concrete composition onto a surface to be paved; and compacting the applied electrically conductive asphalt concrete composition.

24 . The method of claim 23 , wherein said providing the electrically conductive asphalt concrete composition comprises:
mixing the mineral filler, the aggregate, and the plurality of conductive carbon microfibers to form a carbon fiber-aggregate-filler blend; drying the carbon fiber-aggregate-filler blend; preheating the dried carbon fiber-aggregate-filler blend and the asphalt binder; and mixing the pre-heated, dried carbon fiber-aggregate-filler blend and the pre-heated asphalt binder to form the electrically conductive asphalt concrete composition.

25 . The method of claim 24 , wherein the conductive carbon microfibers are between 3 and 12 mm in length.

26 . An electrically conductive compacted asphalt concrete pavement produced according to the method of claim 24 .

27 . A method of forming an electrically conductive asphalt concrete composition comprising:
mixing a mineral filler, an aggregate, and a plurality of conductive carbon microfibers to form a carbon fiber-aggregate-filler blend; drying the carbon fiber-aggregate-filler blend; preheating the dried carbon fiber-aggregate-filler blend and an asphalt binder; and mixing the mineral filler, aggregate, and plurality of conductive carbon fibers to form a carbon fiber-aggregate-filler blend.

28 . The electrically conductive asphalt concrete produced according to the method of claim 27 .

29 . An electrically conductive asphalt concrete pavement comprising:
a compacted asphalt concrete matrix and a plurality of conductive carbon microfibers dispersed in said compacted asphalt concrete matrix, wherein said conductive carbon microfibers are the sole source of electrical conductivity in the asphalt, and wherein said conductive carbon microfibers are positioned to effect resistance heating of the compacted asphalt concrete pavement upon application of an electrical current.

30 . The electrically conductive asphalt concrete pavement of claim 29 , wherein said conductive carbon microfibers are present in the compacted asphalt concrete matrix in an amount of less than 2.00% of total volume of the electrically conductive asphalt concrete pavement.

31 . A system for heating pavement comprising:
the electrically conductive

Assignees

• Univ Iowa State Res Found Inc

Inventors

• Ceylan Halil
• Arabzadeh Ali
• Kim Sunghwan
• Sassani Alireza
• Gopalakrishnan Kasthurirangan
• Notani Mohammad Ali

Classifications

• E01C7/262 Primary

  with fibrous material, e.g. asbestos; with animal or vegetal admixtures, e.g. leather, cork (E01C7/265 takes precedence) · CPC title

• C08K3/013

  Fillers, pigments or reinforcing additives · CPC title

• C08L2555/50

  Inorganic non-macromolecular ingredients · CPC title

• C08K2201/004

  Additives being defined by their length · CPC title

• C08L2555/52

  Aggregate, e.g. crushed stone, sand, gravel or cement · CPC title