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US-12617731-B2 - Asphalt containing recycled waste plastic

US12617731B2US 12617731 B2US12617731 B2US 12617731B2US-12617731-B2

Abstract

A superhydrophobic asphalt and a method of its preparation. The superhydrophobic asphalt contains an asphalt layer containing a polymer modified asphalt, preferably a radial SBS modified asphalt, and a polypropylene layer. The polypropylene layer comprises granules of polypropylene thermally fused to the asphalt layer. The superhydrophobic asphalt has a water contact angle of 145 to 170°, above the classification threshold for superhydrophobicity. The method of preparing the superhydrophobic asphalt involves distributing polypropylene granules over the surface of a polymer modified asphalt and curing below the melting temperature of the polypropylene. The asphalt may find use in waterproofing applications such as roofing.

Inventors

  • Muhammad Abubakar DALHAT

Assignees

  • IMAM ABDULRAHMAN BIN FAISAL UNIVERSITY

Dates

Publication Date
20260505
Application Date
20241015

Claims (13)

  1. 1 . A superhydrophobic asphalt containing recycled waste plastic, comprising: an asphalt layer comprising a polymer modified asphalt, wherein the polymer modified asphalt has a softening point of 80 to 95° C., a viscosity at 135° C. of 1575 to 1650 cP, a ductility at 25° C. of 11.5 to 17.5 cm, a flash point of 300 to 360° C., and a performance grade of 76-10; and a polypropylene layer comprising polypropylene granules that are substantially free of fluoropolymers and polyethylene, having a maximum particle size of 177 μm, a minimum particle size of 100 μm, that are thermally fused onto the asphalt layer, wherein: the polypropylene layer is present in an amount of 50 to 125 g per m 2 of polymer modified asphalt layer, has a R a surface roughness of 10 to 50 μm, and the polypropylene particles are mostly attached to the asphalt surface perpendicularly, as opposed to sideways, the polypropylene granules are at least partially embedded in the asphalt layer, and wherein the superhydrophobic asphalt has a water contact angle of 145 to 170°, and a work of adhesion of 1 to 15 mN/m.
  2. 2 . The superhydrophobic asphalt of claim 1 , wherein the polymer modified asphalt has a softening point of 84 to 88° C., a viscosity at 135° C. of 1605 to 1620 cP, a ductility at 25° C. of 13.75 to 15.25 cm, a flash point of 320 to 340° C., and a performance grade of 76-10.
  3. 3 . The superhydrophobic asphalt of claim 1 , wherein the polymer modified asphalt is an elastomer-type polymer modified asphalt.
  4. 4 . The superhydrophobic asphalt of claim 3 , wherein the elastomer-type modified asphalt is styrene-butadiene-styrene (SBS)-modified asphalt.
  5. 5 . The superhydrophobic asphalt of claim 4 , wherein the styrene-butadiene-styrene is a radial styrene-butadiene-styrene and is present in an amount of 0.5 to 10 wt % based on a total weight of the styrene-butadiene-styrene (SBS)-modified asphalt.
  6. 6 . The superhydrophobic asphalt of claim 1 , wherein the polypropylene layer is present in an amount of 80 to 90 g per m 2 of polymer modified asphalt layer.
  7. 7 . The superhydrophobic asphalt of claim 1 , having a work of adhesion of 6.50-9.60 mN/m.
  8. 8 . The superhydrophobic asphalt of claim 1 , wherein at least a portion of a surface of the asphalt layer is an outermost layer of the superhydrophobic asphalt and said portion is smoother than a surface of the same asphalt layer in the absence of the polypropylene granules.
  9. 9 . The superhydrophobic asphalt of claim 1 , wherein the polypropylene layer comprises 230±15 g/m 2 of the polymer modified asphalt.
  10. 10 . The superhydrophobic asphalt of claim 1 , wherein the polypropylene granules have a protrusion portion of 13.5 to 25% of the total size of the polypropylene granules.
  11. 11 . The superhydrophobic asphalt of claim 1 , wherein the polypropylene granules have a minimum particle size of 149 μm.
  12. 12 . The superhydrophobic asphalt of claim 1 , wherein the polypropylene layer has a R a surface roughness of 20 to 40 μm.
  13. 13 . The superhydrophobic asphalt of claim 1 , wherein the superhydrophobic asphalt has a water contact angle of 152 to 156°.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a Continuation of U.S. application Ser. No. 18/520,657, now allowed, having a filing date of Nov. 28, 2023, which is a Division of U.S. application Ser. No. 17/398,522, now allowed. STATEMENT OF PRIOR DISCLOSURE BY THE INVENTORS Aspects of this technology are described in the article “Water resistance and characteristics of asphalt surfaces treated with micronized-recycled-polypropylene waste: Super-hydrophobicity” published in Construction and Building Materials, 2021, Vol. 285, Page 122870, available on Mar. 11, 2021, which is incorporated herein by reference in its entirety. BACKGROUND OF THE INVENTION Field of the Invention The present disclosure relates to a method of preparing a superhydrophic asphalt, a superhydrophic asphalt surface, and a superhydrophobic asphalt produced by the method. Discussion of the Background The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present invention. Asphalt binder is one of the oldest known civil engineering materials employed for roofing, damp proofing, and waterproofing applications. This is mainly because asphalt binder is water-resistant, a property that makes it suitable for such applications. However, studies have shown that conventional and modified asphalt binders are only hydrophobic, not superhydrophobic (SH) [M. A. Dalhat, and A. Y. Adesina, Constr. Build. Mater. 240 (2020), incorporated by reference herein in its entirety]. Hydrophobic surfaces are characterized by Water Contact Angle (WCA) value that is greater than 90° and less than 145°, while Superhydrophobic surfaces exhibit WCA greater than 145° [K. Y. Law, J. Phys. Chem. Lett. 5 (4) (2014) 686-688]. Superhydrophobic surfaces possess exceptional water resistance properties, such that they are non-wetting due to their high WCA [J. Jeevahan, et. al., J. Coatings Technol. Res. 15 (2) (2018) 231-250]. Superhydrophobic surfaces hold several advantages over hydrophobic surfaces for engineering applications such as anti-icing, dust/mud self-cleaning, and corrosion resistance [X. Yan, et. al., in: 2012 Int. Conf. High Volt. Eng. Appl., 2012, pp. 282-285; C. Peng, et. al., Constr. Build. Mater. 264 (2020) 120702; C. Yu, et. al., Chem. Eng. Res. Des. 155 (2020) 48-65; M. Cui, et. al., Surf. Coatings Technol. 347 (2018) 38-45]. Snow build-up on roof tops is still an issue that results in accidents during manual cleaning [P. O. Bylund, et. al., Int. J. Inj. Contr. Saf. Promot. 23 (1) (2016) 105-109]. Snow build-up can lead to roof collapse due to overload and high energy requirements for indoor heating [A. C. Altunişik, et. al., Eng. Fail. Anal. 72 (2017) 67-78; O. Michael and W. Jennifer, Snow-Related Roof Collapse during the Winter of 2010-2011: implications for Building Codes, 2014; and M. Zhao, et. al., Build. Environ. 87 (2015) 82-91]. Accumulation of dust on asphalt roofs leads to soiling which in turn leads to fungal growth and degradation in high rainfall areas [P. Berdahl, et. al., Constr. Build. Mater. 22 (4) (2008) 423-433]. All of these aforementioned problems can be minimized or eliminated if roof surfaces can be made superhydrophobic. Recycling is still considered among the key strategies of managing the plastic waste crisis of this era [R. C. Thompson, et. al., Philos. Trans. R. Soc. B Biol. Sci. 364 (1526) (2009) 2153-2166]. Studies have shown that unless a high plastic waste recycling rate and similar stringent waste management targets are achieved, the current environmental issues associated with plastic waste will worsen past the middle of the 21th century [L. Lebreton and A. Andrady, Palgrave Commun. 5 (2019) 6]. One facet of improving plastic recycling is to identify and create more products and uses for recycled plastic materials. The use of recycled polypropylene for preparing superhydrophobic materials may provide an important environmental benefit. A wide variety of different asphalt formulations and asphalt additives have been investigated to determine and improve hydrophobicity. Study of the moisture susceptibility of asphalt mixtures reveals that the WCA of 60-70 penetration grade binder and its modified version containing wax and nano-materials lies in the range of 102°-105° [M. Arabani, et. al., J. Mater. Civ. Eng. 24 (7) (2012) 889-897]. In a study of asphalt binder surface free energy, a WCA of 60-100 penetration grade asphalt binders from six different sources was evaluated [A. Bahramian, Evaluating surface energy components of asphalt binders using Wilhelmy plate and sessile drop techniques, Royal Institute of Technology (KTH) (2012)]. The estimated WCA of the various asphal