Highly visco-elastic warm-mix modifier composition and their manufacturing method thereof; and compositions of virgin and recycled modified warm-mix asphalt concrete mixtures and their manufacturing method thereof

Abstract

The first priority of this invention is to provide the composition and the manufacturing method of a novel highly visco-elastic warm-mix modifier that can be added to asphalt binders for the purpose of reducing environmental pollution, saving natural resources by recycling RAP aggregates, reducing construction cost, and minimizing maintenance cost by extending pavement life-cycle. The highly visco-elastic warm-mix modifier may be manufactured by adding highly viscous and general purpose polymers to elastic polymers in the warm mix modifier. Warm mix additives, including waxes, oils and elastic materials, may also be introduced to the highly visco-elastic warm-mix modifier. In more details, the invention is characterized to manufacture the novel modified recycled (or regular) warm-mix asphalt concrete mixture by heating and mixing 0.5-20 weight parts of the highly visco-elastic warm-mix modifier.

Claims

1. A highly viscoelastic, warm-mix modifier for asphalt pavements, including recycled asphalt pavements, the highly viscoelastic, warm-mix modifier comprising: a highly viscoelastic modifier comprising: at least 10% and not more than 90% by weight of a viscous polymer component comprising: a highly viscous polymer selected from the group consisting of polyethylene-terephthalate (PET) and nylon; and a medium viscous polymer; and at least 10% and not more than 90% by weight of a highly elastic polymer component; and not more than 100% of a warm-mix additive component comprising at least one warm mix additive; and a reaction agent component, wherein the reaction agent is selected from the group consisting of maleic anhydride, benzoyl peroxide, acetaldehyde, and platinum catalyst, and wherein the highly viscoelastic, warm-mix modifier is a powder at an ambient temperature.

2. The highly viscoelastic, warm-mix modifier of claim 1, the medium viscous polymer being selected from the group consisting of: low density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high density polyethylene (HDPE), polyvinyl-acetate (PVA), ethylene-vinyl-acetate (EVA) copolymer, and polybutene.

3. The highly viscoelastic, warm-mix modifier of claim 1, the highly elastic polymer component being selected from the group consisting of: styrene-butadiene-styrene (SBS), styrene-butadiene rubber (SBR), SBR latex, styrene-isobutylene-styrene (SIS), styrene-ethylene-butadiene-styrene (SEBS), crumb rubber, waste rubber powder, natural rubber powder, and liquid natural rubber.

4. The highly viscoelastic, warm-mix modifier of claim 1, the warm-mix additive component being selected from the group consisting of: 12-hydroxy stearic acid, hydrogenated castor oil, petroleum resin, pine wax, ethylene-vinyl-acetate (EVA) copolymer wax, polyethylene (PE) wax, polyamide wax, maleic PE wax, ethylene-vinyl-acetate (EVA) emulsion, acryl emulsion, styrene-butadiene-rubber (SBR) emulsion, aromatic process oil, aliphatic process oil, mixed processing oil of aromatic and aliphatic oils, cutback asphalt, heavy oils, A, B & C bunker oil, asphalt emulsion, industrial oils, plant oils, and animal oils.

5. A warm-mix modified asphalt concrete mixture including a modified recycled asphalt concrete mixture comprising 0.5-20 parts by weight (pbw) of the highly viscoelastic warm-mix modifier of claim 1 per 1000-1020 pbw of a warm mix modified asphalt concrete mixture.

6. A warm-mix modified asphalt concrete mixture including a modified recycled asphalt concrete mixture comprising 0.5-20 parts by weight (pbw) of the highly viscoelastic warm-mix modifier of claim 2 per 1000-1020 pbw of a warm mix modified asphalt concrete mixture.

7. A warm-mix modified asphalt concrete mixture including a modified recycled asphalt concrete mixture comprising 0.5-20 parts by weight (pbw) of the highly viscoelastic, warm-mix modifier of claim 3 per 1000-1020 pbw of a warm mix modified asphalt concrete mixture.

8. A warm-mix modified asphalt concrete mixture including a modified recycled asphalt concrete mixture comprising 0.5-20 parts by weight (pbw) of the highly viscoelastic, warm-mix modifier of claim 4 per 1000-1020 pbw of a warm mix modified asphalt concrete mixture.

9. The highly viscoelastic, warm-mix modifier of claim 1, wherein all components of the highly viscoelastic, warm-mix modifier are heated, melted and well mixed to make a uniform melt which is sent through an extruder and cooled and cut to make solid pellets which are further made into fine particles or powders.

10. A warm-mix modified asphalt concrete mixture including a modified recycled asphalt concrete mixture comprising 0.5-20 pbw the highly viscoelastic, warm-mix modifier of claim 9 per 1000-1020 pbw of a warm-mix modified asphalt concrete mixture.

11. A warm-mix modified asphalt concrete mixture as in claim 10 further containing 2-50 pbw of fillers per 1000-1020 pbw of a warm-mix modified asphalt concrete mixture.

12. A warm-mix modified asphalt concrete mixture as in claim 11 wherein the at least one filler being selected from the group consisting of aggregate powder, limestone powder, furnace slag powder, cellulose fiber, glass fiber, polymer fiber, carbon black, fly ash, glass fiber, clay powder, calcium carbonate powder, cement, and steel-making powder.

Description

BRIEF EXPLANATION OF FIGURES

(1) FIG. 1: I-Temperature reductions of single & combined warm-mix additives.

(2) FIG. 2: II-Temperature reductions of single & combined warm-mix additives.

(3) FIG. 3: Elastic effect of the Sasobit-wax containing an elastic material (R).

(4) FIG. 4: Elastic effect of a single warm-mix additive (CM) containing an elastic material (R).

(5) FIG. 5: Elastic effect of a combined warm-mix additive (CM+HCO) containing an elastic material (R).

EXAMPLES FOR BEST PRACTICES OF INVENTION

(6) Compositions of highly visco-elastic warm-mix modifiers for the practice (1, 2, 3) and the comparison (1, 2, 3) are listed in Table 1. Each modifier shown in Table 1 is well mixed with a given amount of an asphalt binder at 180 C. for 2 hours to produce a homogeneous modified asphalt binder. Penetration tests are performed at 25 C. for these modified asphalt binders and the measured results are displayed in Table 1. For physical property measurement of the highly visco-elastic warm-mix modified asphalt concrete mixtures, 955 kg of 19 mm dense-graded aggregates (30 wt % RAP+70 wt % virgin aggregate), 35 kg of an asphalt binder (AC-20), 4 kg of a filler (limestone powder), and 6 kg of each modifier in the practice and those in the comparison are uniformly mixed at 140 C. in the Marshall mixer. Each modified mixture-specimen is made by inserting each concrete mixture into the Marshall mold and compacting both sides in the mold applying 75 Marshall strokes. After each specimen is cured for one day at the room temperature, it is released from the mold. Marshall stability tests are performed for each specimen by following the testing specification and the results are included in Table 1.

(7) Table 1 shows that the penetration value of visco-elastic warm-mix modified asphalt binders and the Marshall Stability of its asphalt concrete mixture in the practice (of this invention) are turned out to be further better, compared to those values of a general asphalt binder or other modified asphalt concrete mixtures in the comparison.

(8) TABLE-US-00001 TABLE 1 Penetra- Marshall Flow tion (100 Stabil- Value g, 5 s, ity (kg, (0.1 mm, Test Compositions 25 C.) 60 C.) 60 C.) Prac- 1 Polyester-LDPE 45 2100 42 tice film composite + crumb rubber + LDPE + aromatic processing oil 2 Nylon + rubber 43 2300 44 powder + carbon black + aromatic processing oil 3 PET-LDPE film 48 1850 43 composite + SBR latex + LDPE Compar- 1 A general asphalt 78 1050 36 ison binder 2 SBS modified 62 1450 42 asphalt binder 3 Gilsonite + crumb 54 1650 32 rubber + HDPE