OLIGOTERPENES AS REJUVENATING AGENT IN ASPHALT

Abstract

An asphalt mixture comprising an oligoterpene composition and reclaimed asphalt and/or virgin asphalt, a method of preparing said asphalt mixture, a bituminous binder-oligoterpene blend and a method for rejuvenating reclaimed asphalt or treating virgin asphalt are disclosed, wherein the oligoterpene composition comprises at least one oligoterpene with at least two isoprene moieties selected from a diterpene, a triterpene, a tetraterpene, a pentaterpene and a hexaterpene. The method of preparing an asphalt mixture comprises mixing the oligoterpene composition with reclaimed asphalt and/or virgin asphalt. The oligoterpene-bituminous binder blend, comprises 0.5-50 wt. % of the oligoterpene composition based on the total weight of the blend. The method for rejuvenating reclaimed asphalt or treating virgin asphalt comprises mixing the oligoterpene composition with reclaimed asphalt or virgin asphalt to form a modified asphalt.

Claims

1. An asphalt mixture comprising an oligoterpene composition and reclaimed asphalt and/or virgin asphalt comprising bituminous binder, wherein the oligoterpene composition comprises at least one oligoterpene with at least two isoprene moieties selected from a diterpene, a triterpene, a tetraterpene, a pentaterpene and a hexaterpene.

2. The asphalt mixture of claim 1 comprising reclaimed asphalt and, optionally, further comprising at least one of additional bituminous binder and an aggregate.

3. The asphalt mixture of claim 1 comprising virgin asphalt, wherein the virgin asphalt optionally comprises polymer modified bitumen.

4. The asphalt mixture of claim 1 further comprising at least one supplementary component selected from an elastomer, plastomer, a non-bituminous binder, an adhesion promoter, a softening agent and a rejuvenating agent other than an oligoterpene.

5. The asphalt mixture of claim 1 wherein the oligoterpene composition comprises a mixture of a diterpene, a triterpene, a tetraterpene, a pentaterpene and a hexaterpene.

6. The asphalt mixture of claim 1 wherein the asphalt mixture comprises 0.01-20 wt. % of the oligoterpene, wherein the % by weight is based on the total weight of the asphalt mixture.

7. The asphalt mixture of claim 1 wherein the asphalt mixture comprises at least 15 wt. % of the reclaimed asphalt, wherein the % by weight is based on the total weight of the asphalt mixture.

8. The asphalt mixture of claim 1 wherein the oligoterpene composition comprises at most 0.5 wt. % of monoterpene, wherein the % by weight is based on the total weight of the oligoterpene composition.

9. The asphalt mixture of claim 8 wherein the oligoterpene composition is free from monoterpene.

10. The asphalt mixture of claim 1 wherein the oligoterpene composition comprises an oligoterpene with at least one unit of the structure

11. A method of preparing the asphalt mixture of claim 1 comprising mixing an oligoterpene composition with reclaimed asphalt and/or virgin asphalt, wherein the oligoterpene composition comprises at least one oligoterpene with at least two isoprene moieties selected from a diterpene, a triterpene, a tetraterpene, a pentaterpene and a hexaterpene.

12. The method according to claim 11 comprising a) first mixing a bituminous binder with the oligoterpene composition to provide a bituminous binder-oligoterpene blend, and then b) mixing the blend with the reclaimed asphalt and, optionally, with at least one of additional bituminous binder, aggregate, an elastomer, a plastomer, a non-bituminous binder, an adhesion promoter, a softening agent and an additional rejuvenating agent other than an oligoterpene, to form an asphalt mixture comprising reclaimed asphalt.

13. The method according to claim 11 comprising a) first mixing a bituminous binder comprising virgin bitumen with the oligoterpene composition to provide a bituminous binder-oligoterpene blend; and then b) mixing the blend with virgin aggregate, and, optionally, with at least one of additional bituminous binder, additional aggregate, an elastomer, a plastomer, a non-bituminous binder, an adhesion promoter, a softening agent and an additional rejuvenating agent other than an oligoterpene, to form an asphalt mixture comprising virgin asphalt.

14. A blend of bituminous binder and an oligoterpene composition comprising 0.5-50 wt. % of the oligoterpene composition wherein the oligoterpene composition comprises at least one oligoterpene with at least two isoprene moieties selected from a diterpene, a triterpene, a tetraterpene, a pentaterpene and a hexaterpene and wherein the % by weight is based on the total weight of the blend.

15. A method for rejuvenating reclaimed asphalt or treating virgin asphalt, comprising mixing an oligoterpene composition with reclaimed asphalt and/or virgin asphalt to obtain a modified asphalt, wherein the oligoterpene composition comprises at least one oligoterpene with at least two isoprene moieties selected from a diterpene, a triterpene, a tetraterpene, a pentaterpene and a hexaterpene.

Description

EXAMPLES

Preparation of Oligoterpene A

[0068] In a 1 L four necked reaction flask, equipped with thermometer, overhead stirrer, nitrogen purge, addition line and a sampling port a slurry of 7.0 g of aluminum chloride (with a purity higher than 98.5% from Acros, Belgium) and 160 g of xylene (with a purity higher than 98% from VWR, The Netherlands) are charged under nitrogen atmosphere. The reactor is heated to a temperature from 45 to 47° C. When this temperature is reached, α-pinene (with purity higher than 94% from Arizona Chemical, Finland) is added at a rate of 2-3.5 grams per minute, to a total of 200 g of α-pinene. After all α-pinene is added the reactor is left at 45-47° C. for 60 minutes. After this time the aluminum chloride is neutralized with 100 g of water. The neutralization is carried out by stirring continuously at 75-80° C. for 15 minutes. Thereafter the stirrer is switched off and the mixture is left to stand for 30 minutes to allow the separation of the organic phase and the aqueous phase. The aqueous phase is then decanted and the organic phase is washed with water. The organic phase is then heated to 120° C. and the evaporated residual water and xylene are condensed and collected. When no more vapor is visibly condensing, the reactor is heated to 180° C. and any volatile material is collected. When no vapor was visibly condensing, the reactor is then heated to 240° C. and a nitrogen sparge was started to strip-off further volatiles until a viscosity specification from 4000 to 4500 mPa.Math.s at 50° C. is reached. The residue obtained is the oligoterpene composition referred to as oligoterpene A.

[0069] The viscosity of the product is measured according to the ASTM D2196 method which uses Brookfield equipment and provides a rotational viscosity measurement.

[0070] The composition of oligoterpene A was determined by GPC according to the ASTM D5296-05 method for determining molecular weight averages and molecular weight distribution of polystyrene by high performance size-exclusion chromatography. 30 μL of a sample of the polymerization product (about 50 mg) dissolved in 2000 μL of THF (99+% from Aldrich, Belgium) was injected to a HPCL machine (HPLC system equipped with a Waters 515 HPLC pump; Waters 717 plus Autosampler; Waters 2414 Refractive Index Detector and Waters Column Heater Module) fitted with a two mixed E columns (from Polymer laboratories): one 50 Angstrom column and a 3 micron guard column. Each sample was run with an isocratic THF solvent system over 35 minutes.

[0071] In order to establish the correlation between the retention time and the Mw, a calibration was performed using a commercially available polystyrene standard with molecular weights from 580 g-mol-l to 380000 g-mol-l (PS 2 EasiCal from Polymer Laboratories, USA)

[0072] The measured Mw of each of the components of the oligoterpene A was obtained based on their retention time and by using the polystyrene calibration as reference values.

[0073] The measured Mw of the monoterpene α-pinene (with a theoretical Mw of 136) was determined under the same conditions and was found to be of 116. This measurement was used to correlate the measured Mw values (based on the polystyrene calibration) with the theoretical Mw, for each of the components identified in the GPC chromatogram of the oligoterpene A composition. The results are given in Table 1.

TABLE-US-00001 TABLE 1 Type of Oligoterpene Peak Area Measured MW values (theoretical MW values) α-Pinene  100% 116 Monoterpene (136) Oligoterpene A 38.0% 208 Diterpene (272) 22.5% 334 Triterpene (408) 16.2% 467 Tetraterpene (544)  6.7% 593 Pentaterpene (680) 14.7% 689 Hexaterpene (816)

Preparation of Test Samples

[0074] Samples of bituminous binder were obtained from several suppliers. Non-modified bitumen was obtained from Q8, The Netherlands. Polymer modified bitumen was obtained from Shell, The Netherlands. Aged bitumen was obtained according to ASTM D6521 using the pressure aging vessel, whereby a PEN 35/50 graded bitumen was aged using a temperature of 100° C. for 40 hours.

[0075] The samples for dosing the additives were prepared by heating the bituminous binders to 135° C. for 90-120 minutes to obtain a homogenous bitumen sample. From the heated container a predetermined weight was added into a 50 ml beaker. Additives were dosed at a dosage level of 5 wt. % to the bituminous binders. The samples were stirred and placed back into the oven for 10 minutes. After 10 minutes samples were taken out of the oven and stirred again. The samples are ready to be used for further evaluation.

TABLE-US-00002 TABLE 2 Sample Virgin Aged (additive) bitumen bitumen Additive Comp. Ex. 1 (virgin, no additive)***  100 g Comp. Ex. 2 (virgin, no additive)**  100 g Comp. Ex. 3 (aged, no additive)* 100 g Comp. Ex. 4 (mix, no additive)   30 g  70 g Comp Ex. 5 (flux oil) 26.5 g  70 g 3.5 g Ex. 1 (oligoterpene A) 26.5 g  70 g 3.5 g Ex. 2 (oligoterpene B) 26.5 g  70 g 3.5 g Comp Ex.6 (flux oil)* 95 5 Ex. 3 (oligoterpene A)* 95 5 Ex. 4 (oligoterpene B)* 95 5 Comp Ex 7 (flux oil)** 95 5 Ex. 5 (oligoterpene A)**    95 g*   5 g Ex. 6 (oligoterpene B)**    95 g*   5 g Comp Ex 8*** 95 5 Ex. 7 (oligoterpene A)***   95 g   5 g Ex. 8 (oligoterpene B)***   95 g   5 g *Laboratory aged binder with PAV for 40 hours at 90° C. **polymer modified bitumen Styrelf ex-Shell ***PEN 35/50 ex-Q8 petroleum

Measurements and Results

[0076] A sample of each bitumen composition was taken for measuring the Ring & Ball softening point, the glass transition temperature and the rheological profile (Tables 2, 3 and 4).

[0077] The Ring & Ball softening point was measured in water according to the Ring and Ball method ASTM E28-99. A sample of the bitumen compositions prepared above was poured into a metal ring, when still warm and subsequently cooled. The ring was cleaned in such a way that the material fitted the ring, a steel ball was placed resting on top of the material. The ring and ball were lowered into a beaker containing water, and the water was heated at 5° C. per minute while being stirred. When the ball dropped completely through the ring, the temperature of the water was recorded. The temperature value is reported in as the Ring & Ball softening point.

[0078] The Ring & Ball softening point of bitumen is an indicator of the stiffness of asphalt wherein the bitumen is used.

[0079] The glass transition temperature (Tg) was measured with a Methler DSC apparatus with the following parameters: [0080] Gas: Nitrogen 65 ml/min [0081] Cup: Standard Aluminum 40 μl cup with small hole on the lid [0082] Temperature: [0083] From 25.0° C. to −60.0° C. at a rate of 10° C. per minute [0084] From −60.0° C. to 25.0° C. at a rate of 10° C. per minute

[0085] The glass transition temperature of bitumen is an indicator of the brittleness of asphalt wherein the bitumen is used.

[0086] More in depth analysis was made using a Dynamic Shear Rheometer (DSR). For this study the test used a 10 mm plate, with a 2.5 mm gap and was run at one frequency (10 rad/s) in a range of −30° C. to +100° C. These measurements are used to assess the performance of the bituminous binder at high, intermediate and low temperatures.

[0087] Viscoelastic behavior of the bitumen at temperatures below 15° C. is an indicator of the tendency to crack at low temperatures of asphalt wherein the bitumen is used. The viscoelastic behavior may be expressed in terms of the Storage Modulus and the Loss Modulus. The lower the Storage Modulus and the Loss Modulus the lower is the tendency to crack.

TABLE-US-00003 TABLE 3 Ring 1-Glass 2-Glass and Ball Pene- transition transition Sample Softening tration temperature temperature (additive) point (° C.) (dmm) −Tg (° C.) −Tg (° C. Comp. Ex. 1 54.2 30 −19.9 16.7 (virgin, no additive)*** Comp. Ex. 2 70.3 49 −28.5 6.9 (virgin, no additive)** Comp. Ex. 3 66.8 13 −22.4 14.7 (aged no additive)* Comp. Ex. 4 61.3 20 −19.5 17.7 (mix, no additive) Comp Ex. 5 (flux oil) 56.2 36 −23.1 13.7 Ex. 1 (oligoterpene A) 57.7 30 −20.8 15.5 Ex. 2 (oligoterpene B) 60.9 18 −18.1 19.0 Comp Ex. 6 (flux oil)* 62.0 21 −17.5 20.7 Ex. 3 (oligoterpene A)* 62.9 18 −20.3 15.9 Ex. 4 (oligoterpene B)* 67.6 12 −20.4 14.9 Comp. Ex. 7 (flux oil)** 69.3 64 −29.0 6.3 Ex. 5 (oligoterpene A)** 69.0 59 −27.2 8.1 Ex. 6 (oligoterpene B)** 70.6 41 −26.2 12.2 Comp. Ex. 8(flux oil))*** 43.5 93 −22.9 12.0 Ex. 7 (oligoterpene A)*** 54.9 26 −21.1 14.9 Ex. 8 (oligoterpene B)*** 51 46 −18.4 19.3 *Laboratory aged binder with PAV for 40 hours at 90° C.; **polymer modified bitumen Styrelf ex-Shell; ***PEN 35/50 ex-Q8 petroleum

TABLE-US-00004 TABLE 4 Temperature [° C.] −20 −15 −10 −5 0 5 10 15 20 25 Sample (additive) Storage Modulus [MPa] Comp. Ex. 1 (virgin, no additive)*** 593 488 316 218 141 84.8 35.8 12.5 5.4 2.1 Comp. Ex. 2 (virgin, no additive)** 380 241 171 93.4 57.6 24.3 12.1 5.7 1.7 0.7 Comp. Ex. 3 (aged no additive)* 499 400 306 191 108 69.5 41.6 16.5 8 Comp. Ex. 4 (mix, no additive) 483 339 208 145 95.8 44.9 24.1 11.8 3.55 Comp Ex. 5 (flux oil) 565 399 296 174 115 71.5 30.4 10.1 4.4 1.9 Ex.1 (oligoterpene A) 606 428 272 190 127 63 35.8 12.9 6 2.6 Ex. 2 (oligoterpene B) 433 345 211 143 92.7 44.3 24.7 12.6 3.8 Comp Ex.6 (flux oil)* 338 207 137 89.4 44.9 27 10.1 4.6 Ex.3 (oligoterpene A)* 327 243 135 86.4 41.1 23.3 12.3 4 Comp. Ex. 7 (flux oil)** 326 200 139 71.6 43.6 17.3 8.2 3.6 0.9 0.4 Ex. 5 (oligoterpene A)* * 320 197 132 85.3 39.3 21.4 7 3 1.2 0.3 Ex. 6 (oligoterpene B)** 426 317 205 137 85.6 41 14.8 6.4 2.5 0.7 Comp. Ex. 8(flux oil))*** 314 253 190 112 74.5 36 18.9 5.9 2.5 0.5 Ex. 7 (oligoterpene A)*** 532 425 262 171 103 43.3 22.5 7 2.9 0.6 Ex. 8 (oligoterpene B)*** 672 574 406 291 193 90.8 50.9 18.3 8.2 2 Sample (additive) Loss Modulus [MPa] Comp. Ex. 1 (virgin, no additive)*** 81.6 90.1 92.9 83.3 68.3 51.5 29.7 14.3 7.8 3.9 Comp. Ex. 2 (virgin, no additive)** 86.1 77.3 67.3 47.6 34.8 18.8 11.2 6.2 2.4 1.2 Comp. Ex. 3 (aged no additive)* 87 81.6 69.2 51 39 27.7 14.4 8.4 Comp. Ex. 4 (mix, no additive) 89.5 88.1 75.7 63.1 49 30.5 19.7 11.7 4.7 Comp Ex. 5 (flux oil) 80 92.1 88.7 72.5 58.4 43.7 24.6 11 5.9 3 Ex.1 (oligoterpene A) 84.1 97.4 89.3 76.2 62.1 40.2 27.4 13 7.3 3.8 Ex. 2 (oligoterpene B) 77.2 79.7 72.1 61.1 48.6 30.6 20.6 12.7 5.3 Comp Ex.6 (flux oil)* 88.4 75 60.8 47.2 30.1 21.2 10.3 5.7 Ex.3 (oligoterpene A)* 88.4 80.3 60.1 46.3 28.3 18.9 11.9 5.2 Ex. 4 (oligoterpene B)* 80.2 78.7 68.1 56.4 43.8 26.8 18.1 Comp. Ex. 7 (flux oil) ** 88 85.3 75 61.7 47 28.9 13.8 7.3 3.5 1.3 Ex. 5 (oligoterpene A)* * 81.8 71.3 58.7 45.3 26.8 17.2 7.4 3.8 1.9 0.6 Ex. 6 (oligoterpene B)** 88 85.3 75 61.7 47 28.9 13.8 7.3 3.5 1.3 Comp. Ex. 8(flux oil))*** 48.2 54.7 56.6 50.5 43.1 29 18.9 8.3 4.4 2.1 Ex. 7 (oligoterpene A)*** 74.3 87.9 86.1 74.3 58.1 34.3 22.1 9.6 4.9 1.6 Ex. 8 (oligoterpene B)*** 68.4 83.6 96.6 94 81.8 56.5 39.9 20.2 11.4 4 *Laboratory aged binder with PAV for 40 hours at 90° C.; **polymer modified bitumen Styrelf ex-Shell; ***PEN 35/50 ex-Q8 petroleum

TABLE-US-00005 TABLE 5 Comparison in virgin PEN 35/50 PEN graded bitumen Sample Ring & Ball Storage Loss (additive) softening point Tg Modulus Modulus Comp Ex. 5 (flux oil) + + + + Ex. 1 (oligoterpene A) + + + + Ex. 2 (oligoterpene B) − − − −

TABLE-US-00006 TABLE 6 Comparison in virgin polymer modified bitumen Sample Ring & Ball Storage Loss (additive) softening point Tg Modulus Modulus Comp Ex. 5 (flux oil) − + + + Ex. 1 (oligoterpene A) − + + + Ex. 2 (oligoterpene B) − + − −

TABLE-US-00007 TABLE 7 Comparison in laboratory aged bitumen Sample Ring & Ball Storage Loss (additive) softening point Tg Modulus Modulus Comp Ex. 5 (flux oil) + + + + Ex. 1 (oligoterpene A) + + + + Ex. 2 (oligoterpene B) − − − −

TABLE-US-00008 TABLE 8 Comparison in a mix of 70% aged and 30% virgin bitumen Sample Ring & Ball Storage Loss (additive) softening point Tg Modulus Modulus Comp Ex. 5 (flux oil) + + + + Ex. 1 (oligoterpene A) + + + + Ex. 2 (oligoterpene B) − − − −

[0088] Tables 5-8 present an overview of the performance of each of the additives used with respect to virgin bitumen (Comp. Ex. 4), i.e. the sample with the target performance. A negative sign (−) indicates no improvement or no significant improvement with respect to comparative example 4 and a positive sign (+) indicates an improvement. The higher the number of positive signs the higher the improvement.

[0089] As it can be seen from the results presented in Tables 2, 3, 4 and 5, oligoterpenes act as modifiers for bituminous products altering at least some of the properties. In particular, oligoterpene A (Ex.1) improves the softening point and the glass transition temperature of bitumen mixtures. It improves the low temperature properties of each bituminious product used in the examples. Oligoterpene A also provides an improvement on the storage modulus at temperatures from 0 to 25° C. and on the loss modulus at temperatures from 15 to 25° C. (see tables 2 and 4).