Xue Li

Currently, developing super-tough polyurethanes and their high-performance road sealants that combine high strength, high toughness, and multifunctionality remains a significant challenge. In this work, super-tough polyurethane elastomers (PUAZn-X) were successfully synthesized using polytetrahydrofuran (PTMG) and diphenylmethane diisocyanate (MDI) as raw materials. A hierarchical hydrogen-bonding network was constructed through chain extension with 2,2-bis(hydroxymethyl)propionic acid (DMPA), combined with dynamic zinc-ion coordination crosslinking. The hierarchical hydrogen bonds maintain dynamic equilibrium under external stress, endowing PUAZn-X with high elasticity and fatigue resistance. The coordination bonds between carboxyl groups and Zn2+ enhance intermolecular interactions, resulting in high tensile strength (37.4 MPa) and elongation at break (1557.6%). The metal coordination bonds, associated with both cohesion and adhesion strength, facilitate timely energy dissipation in response to applied external stress, thereby improving adhesion performance. The self-prepared road sealant prepared using PUAZn-X features a low application temperature and exhibits enhanced mechanical properties, adhesion, high-temperature resistance, and water resistance after curing, with a pull-off strength reaching 2.1 MPa. It can mitigate interfacial adhesion failure under external stress. This study thus provides an alternative approach for the design and preparation of advanced road sealants.

This study utilized EVA, SBS, a warm-mix additive and other components as primary materials to prepare a high-performance asphalt anti-rutting additive via a compounding process. Its rutting resistance was evaluated through high-temperature rheological tests, using parameters, such as the rutting factor, as indicators. Fourier Transform Infrared (FTIR) spectroscopy was employed to analyze changes in asphalt functional groups before and after the additive’s addition, exploring the modification mechanism. FM showed how the additive spreads inside the asphalt. The results demonstrate that this anti-rutting additive significantly enhances the asphalt’s resistance to deformation under elevated thermal conditions by forming a dense three-dimensional network structure within the asphalt, while also improving the adhesion to aggregates. This high-elastic composite anti-rutting additive, characterized by its simple preparation process and excellent performance, can effectively enhance the overall rutting resistance of modified asphalt.

A suitable one-component polyurethane resin matrix for the sealant was developed by screening different chain extenders and soft segment types. This polyurethane was then compounded with nano-calcium carbonate filler and dibutyl phthalate to form the final one-component polyurethane sealant. The resulting PUA sealant was systematically evaluated through measurements of its mechanical properties, adhesion performance, curing time, and thermal behavior, providing a comprehensive assessment of its overall performance.

To enhance the comprehensive performance and interfacial adhesion of conventional emulsified asphalt, an epoxy-functionalized waterborne polyurethane modified emulsified asphalt (EFPU-MEA) was developed using an epoxy-functionalized waterborne polyurethane (EFPU) emulsion and an isocyanate curing agent. Experimental evaluations show that the EFPU-MEA achieves a tensile strength of 1.11 ± 0.05 MPa and an elongation at break of 782.5 ± 45%, demonstrating a well-balanced flexibility and deformation resistance. The interfacial bond between EFPU-MEA and aggregates exhibited robust durability under various stressors, including thermal fluctuations, low-temperature cracking, chemical corrosion, and moisture damage. Quantitative “sandwich” pull-out and shear tests determined the optimal modifier content and spraying quantity to be 15–20% and 1.0 kg/m², respectively. Under these conditions, the system maintained high bond strength following severe freeze–thaw cycles and chemical erosion. Mechanistically, fluorescence microscopy (FM) confirmed a uniform dispersion of EFPU within the asphalt matrix, providing effective physical reinforcement. Furthermore, surface free energy (SFE) analysis and Fourier Transform Infrared (FTIR) spectroscopy revealed that internal chemical crosslinking restructures the binder’s surface thermodynamics, significantly increasing the surface polarity and adhesion work. Finally, road performance tests—including marshall stability, wet track abrasion, and rutting resistance—verified the engineering durability of the EFPU-MEA mixture. These findings provide a theoretical and practical basis for the use of EFPU-MEA in extending the service life of high-grade highway pavements.

The application of waterborne polyurethane (WPU) in emulsified asphalt (EA) is often restricted by limited compatibility and insufficient comprehensive performance. Herein, a high‐performance WPU (HWPU) was synthesized via a hybrid soft‐segment strategy using hydroxyl‐terminated polybutadiene (HTPB) and polytetramethylene ether glycol (PTMG). The nonpolar PB segments promoted microphase separation and enhanced interfacial compatibility with asphalt. The resulting HWPU film achieved a tensile strength of 24.4 MPa and 1456% elongation. Consequently, HWPU‐modified EA (HWPU‐MEA) demonstrated superior high‐temperature performance, evidenced by a rutting factor (G*/sin δ ) of 26.1 kPa at 110°C. MSCR tests at 90°C revealed outstanding elastic recovery ( R _0.1 = 99.68%; R _3.2 = 72.41%) and minimal permanent deformation ( J _{nr 0.1} = 0.43 × 10 ⁻³ kPa ⁻¹ ; J _{nr 3.2} = 0.36 × 10 ⁻¹ kPa ⁻¹ ). Additionally, HWPU‐MEA displayed remarkable low‐temperature crack resistance and extended fatigue life. Mechanism analysis attributes these performance enhancements to the formation of a continuous HWPU network structure within the asphalt matrix at an optimal dosage of 15%–20%. This work provides an effective modification strategy for producing high‐performance paving materials suitable for heavy‐duty road engineering.

To broaden clean asphalt modification methods, this study employs a composite polymer of maleic anhydride-grafted styrene-butadiene-styrene (MA-g-SBS) and styrene-butadiene-styrene (SBS) as a modifier. The composite is formulated into polymer latex and used to modify emulsified asphalt. Routine performance tests were conducted on MA-g-SBS/SBS composite latex-modified emulsified asphalt (MSMEA) with varying ratios to determine the optimal composition. The ideal ratio was found to be MA-g-SBS:SBS = 1:4. Subsequently, conventional property tests, rheological analyses, microphase structure observations, and bending beam creep tests were conducted on MSMEA with the optimal ratio to assess the impact of the composite latex on asphalt performance. Findings indicated that increasing the latex content significantly enhanced the softening point and ductility while reducing penetration. These macroscopic improvements were notably superior to those achieved with single SBS latex modification. Fluorescence microscopy revealed that at low dosages, the MA-g-SBS/SBS composite dispersed uniformly as point-like structures within the asphalt. At higher dosages (above 5%), a distinct network structure emerged. The addition of the composite latex raised the complex shear modulus and rutting factor while reducing the phase angle, with pronounced fluctuations observed between 4% and 5% dosages. This suggests a substantial enhancement in the high-temperature performance of the emulsified asphalt, attributed to the formation of the network structure. FT-IR results confirmed that a chemical reaction occurred during the modification process. Additionally, the bending beam creep test demonstrated that the composite latex reduced asphalt brittleness and improved its low-temperature performance.

Ultraviolet (UV) radiation accelerates the aging of asphalt pavements and shortens the service life of the pavement. To effectively mitigate the impact of UV aging on asphalt performance, a novel composite anti-UV aging agent, 2-hydroxy-4-n-octyoxybenzophenone/pigment violet (UV-531/PV), was developed. After UV-accelerated aging, the modified asphalt samples were characterized by conventional performance tests, Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and a dynamic shear rheometer (DSR). The results show that UV-531/PV-composite-modified asphalt maintains excellent conventional properties after UV aging. The FTIR testing showed that the changes in carbonyl index (I_c=o) and sulfoxide index (I_s=o) of the composite-modified asphalt were significantly smaller than those of the matrix asphalt, indicating the less oxidation degree of the composite-modified asphalt. The GPC test results showed that the change in molecular weight of the composite-modified asphalt after UV aging was less than that of the matrix asphalt. DSR results showed that UV-531/PV-modified asphalt exhibited higher viscoelasticity and higher rutting resistance than unmodified asphalt. This study proposes a new method for preparing anti-UV aging asphalt, which can be used for micro-surfacing, fog sealing or ultra-thin overlay on road surfaces.