Smart rutting and cracking resistant asphalt pavement incorporating shape memory polymers

Patent metadata

Field	Value
Publication number	US-10954390-B2
Application number	US-201916299223-A
Country	US
Kind code	B2
Filing date	Mar 12, 2019
Priority date	Mar 13, 2018
Publication date	Mar 23, 2021
Grant date	Mar 23, 2021

Abstract

The low temperature cracking and high temperature rutting of polymer-modified asphalt concrete pavement can be reduced. The composite includes asphalt and at least one polymer that expands at low temperature, triggered by cooling-induced tensile stress, to reduce thermal cracking. The composite includes at least one polymer that expands at high temperature, so that the composite recovers after compression induced by traffic loading at higher temperatures, thereby reducing rutting. The system reduces thermal stress, and reduces or even eliminates thermal cracking and rutting. Shape memory polymers (SMPs) are used to improve asphalt compositions so that they better resist both thermal cracking and rutting. The SMP(s) can be incorporated into the asphalt, or a portion of fine aggregates can be replaced with SMP particles or SMP fibers, or aggregate replacement and asphalt modification can be combined.

First claim

What is claimed:

1. An asphalt concrete resistant both to permanent deformation and to cracking; said asphalt concrete comprising a composite of asphalt, aggregate, and one or more shape memory polymers; wherein:
(a) at least one of said one or more shape memory polymers exhibits a one-way shape memory effect over at least a portion of the temperature range +20° C. to +70° C., wherein the one-way shape-memory effect is repeatable over multiple cycles of heating and cooling, and over multiple cycles of weight-bearing loading;
(b) at least one of said one or more shape memory polymers is selected from the group consisting of cross-linked polybutadiene, cross-linked polybutadiene with 98% or higher cis content, cross-linked polycyclooctene, cross-linked poly(ethylene-co-vinyl acetate), an ionomer, and combinations thereof; and exhibits a two-way shape memory effect over at least a portion of the temperature range −50° C. to 0° C., wherein the two-way shape memory effect is repeatable over multiple cycles of heating and cooling, and over multiple cycles of weight-bearing loading;
(c) the one-way shape memory effect reduces permanent deformation of the asphalt concrete, over at least a portion of the temperature range +20° C. to +70° C., as compared to an otherwise-identical composite lacking said one or more shape memory polymers; and
(d) the two-way shape memory effect reduces cracking of the asphalt concrete, over at least a portion of the temperature range −50° C. to 0° C., as compared to an otherwise-identical composite lacking said one or more shape memory polymers.

2. The asphalt concrete of claim 1 , wherein at least one of said one or more shape memory polymers: (a) is integrally mixed into said asphalt; or (b) is integrally mixed into said aggregate, as particles having overlapping size and shape with the size and shape of the particles of the aggregate; or (c) comprises a geogrid that reinforces the asphalt concrete; or (d) comprises a stress-absorbing membrane or tack coat layer; or (e) a combination of two or more of the above.

3. The asphalt concrete of claim 1 , wherein at least one of said shape memory polymers is a thermoset, one-way shape memory polymer selected from the group consisting of (a) an epoxy resin selected from the group consisting of diglycidyl ether of bisphenol A, 1,3-bis (aminomethyl)cyclohexane and bisphenol A glycerolate dimethacrylate, cross-linked with a cross-linker selected from the group consisting of a diamine, a polycarboxylic acid, phthalic anhydride, tricarballylic acid, and a rigid isophorone diamine; (b) a polyurethane, the reaction product of a di- or polyisocyanate with a polyol, a polyimide, poly-phenylmaleimide, and poly-tris(4-aminophenyl)amine; and (c) polystyrene, the reaction product of polystyrene with butyl acrylate, vinyl neodecanoate, and soybean oil; and (d) combinations thereof.

4. The asphalt concrete of claim 1 , wherein at least one of said shape memory polymers is a thermoplastic, one-way shape memory polymer selected from the group consisting of poly(ethylene-co-methacrylic acid), ethylene-methacrylic acid copolymer, polyether ether ketone, polypropylene, a polystyrene, a polyurethane, polynorbonene, a polyester, a polyether, polyethylene terephthalate, polyethyleneoxide, poly(1,4-butadiene), poly(vinyl acetate), polyamide-6 (nylon-6), poly(tetrahydrofuran), poly(2-methyl-2-oxazoline), poly(ethylene adipate), 1,1′-methylene-bis(4-isocyanatobenzene)/1,4-butanediol, poly(ε-caprolactone), polyvinyl chloride, polyethylene/polyamide blend, and combinations thereof.

5. The asphalt concrete of claim 1 , wherein at least one of said one or more shape memory polymers has a decomposition temperature 200° C. or higher.

6. The asphalt concrete of claim 1 , wherein at least one of said one or more shape memory polymers with a two-way shape memory effect expands 5% or more when the temperature drops from 0° C. to −60° C.

7. The asphalt concrete of claim 1 , wherein at least one of said one or more shape memory polymers with a one-way shape memory effect expands 2% or more when the temperature rises from 0° C. to 60° C.

8. The asphalt concrete of claim 1 , wherein said asphalt concrete is uncured, and wherein said one or more shape memory polymers comprise particles or fibers that are coated with a 1-10 μm layer of mineral filler to inhibit aggregation of said particles or fibers to one another or to other components of said asphalt concrete, prior to curing.

9. The asphalt concrete of claim 1 , wherein said one or more shape memory polymers consist essentially of particles or fibers having a maximum dimension 10 mm or less.

10. The asphalt concrete of claim 1 , wherein said one or more shape memory polymers comprise between 1% and 20% of said asphalt concrete by mass.

11. The asphalt concrete of claim 1 , wherein said asphalt concrete is the product of dispersing one or more cured shape memory polymers into an asphalt matrix.

12. The asphalt concrete of claim 1 , wherein said asphalt concrete is the product of mixing asphalt with one or more uncured shape memory polymers and a crosslinker, using a compounder or using an extrusion machine, followed by curing.

Assignees

• Li Guoqiang
• Univ Louisiana State

Inventors

• Li Guoqiang

Classifications

• C08L2555/86

  Polymers containing aliphatic hydrocarbons only, e.g. polyethylene, polypropylene or ethylene-propylene-diene copolymers · CPC title

• E01C7/265

  with rubber or synthetic resin, e.g. with rubber aggregate, with synthetic resin binder (for thin overlays or surface dressings E01C7/35) · CPC title

• C08L95/00 Primary

  Compositions of bituminous materials, e.g. asphalt, tar, pitch · CPC title

• C08L2555/84

  Polymers comprising styrene, e.g. , polystyrene, styrene-diene copolymers or styrene-butadiene-styrene copolymers · CPC title

• E01C7/262

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