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<p>The rheological characteristics of asphalt binders are pivotal for the structural integrity and longevity of pavements. Given the rising traffic volumes and environmental challenges, enhancing asphalt binder properties to withstand diverse temperature conditions and mechanical stresses is essential. The advent of nanotechnology has opened new avenues for improving pavement materials. Despite the known benefits of graphene nanoplatelets (GNPs) in other applications, there is a lack of comprehensive research that systematically evaluates the effect of GNPs on the rheological characteristics of asphalt binders, especially considering both low and high-temperature performance. The present research focused on the evaluation of GNPs-modified asphalt binders. In this regard, modified samples were constructed by adding GNPs in the amount of 0.5 and 1% of asphalt binder weight. Experiments, such as the rotational viscosity (RV), multiple stress creep and recovery (MSCR), and bending beam rheometer (BBR) tests, were conducted. The results of RV test showed that the addition of GNPs did not make any significant change in the increase of asphalt binder viscosity (up to 3% change in viscosity at 135&#xa0;°C). This can be considered a great advantage for keeping the mix temperature constant when producing asphalt mixtures containing this additive. Moreover, MSCR test results at 58, 64, and 70&#xa0;°C under 0.1 and 3.2&#xa0;kPa loads indicated that GNP significantly reduced non-recoverable creep compliance (J<sub>nr</sub>) and stress sensitivity, and increased the traffic level by one grade and percent recovery in modified samples. For example, at 70&#xa0;°C, adding 1% GNP lowered J<sub>nr 0.1</sub> from 9.71&#xa0;kPa⁻¹ to 7.44&#xa0;kPa⁻¹ (≈ 24.2% reduction) and J<sub>nr 3.2</sub> from 14.30&#xa0;kPa⁻¹ to 10.84&#xa0;kPa⁻¹ (23.4% reduction) and raised percent recovery (R) from 1.20 to 2.48% (106.6% increase) under 0.1&#xa0;kPa and from 0.65 to 1.23% (89.2% increase) under 3.2&#xa0;kPa, demonstrating a clear improvement in rut resistance. On the other hand, the two parameters extracted from the Burgers model in this test, namely the creep stiffness’s viscous component and viscous flow-to-elasticity ratio, showed that asphalt binder modification increased the mixture’s resistance against rutting. BBR test results showed creep stiffness increases of 13.7 and 11.7% for 0.5% GNP and m-value declines of 12.9 and 13.4% for 1% GNP at -12&#xa0;°C and − 18&#xa0;°C, respectively, both within PG low-temperature limits and leaving the low-temperature grade unchanged. This study offers valuable insights for policymakers by demonstrating the potential of GNPs to significantly enhance the rheological characteristics of asphalt binders, thereby improving pavement performance.</p>

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Experimental investigation of rheological characteristics of graphene nanoplatelets-modified asphalt binders at low and high temperatures

  • 期刊论文

  • 发表日期：

    2025年9月20日

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  • Mohsen Najafi,
  • Gholamali Shafabakhsh,
  • Saeid Moghimi,
  • Behzad Rahmani

摘要

The rheological characteristics of asphalt binders are pivotal for the structural integrity and longevity of pavements. Given the rising traffic volumes and environmental challenges, enhancing asphalt binder properties to withstand diverse temperature conditions and mechanical stresses is essential. The advent of nanotechnology has opened new avenues for improving pavement materials. Despite the known benefits of graphene nanoplatelets (GNPs) in other applications, there is a lack of comprehensive research that systematically evaluates the effect of GNPs on the rheological characteristics of asphalt binders, especially considering both low and high-temperature performance. The present research focused on the evaluation of GNPs-modified asphalt binders. In this regard, modified samples were constructed by adding GNPs in the amount of 0.5 and 1% of asphalt binder weight. Experiments, such as the rotational viscosity (RV), multiple stress creep and recovery (MSCR), and bending beam rheometer (BBR) tests, were conducted. The results of RV test showed that the addition of GNPs did not make any significant change in the increase of asphalt binder viscosity (up to 3% change in viscosity at 135 °C). This can be considered a great advantage for keeping the mix temperature constant when producing asphalt mixtures containing this additive. Moreover, MSCR test results at 58, 64, and 70 °C under 0.1 and 3.2 kPa loads indicated that GNP significantly reduced non-recoverable creep compliance (Jnr) and stress sensitivity, and increased the traffic level by one grade and percent recovery in modified samples. For example, at 70 °C, adding 1% GNP lowered Jnr 0.1 from 9.71 kPa⁻¹ to 7.44 kPa⁻¹ (≈ 24.2% reduction) and Jnr 3.2 from 14.30 kPa⁻¹ to 10.84 kPa⁻¹ (23.4% reduction) and raised percent recovery (R) from 1.20 to 2.48% (106.6% increase) under 0.1 kPa and from 0.65 to 1.23% (89.2% increase) under 3.2 kPa, demonstrating a clear improvement in rut resistance. On the other hand, the two parameters extracted from the Burgers model in this test, namely the creep stiffness’s viscous component and viscous flow-to-elasticity ratio, showed that asphalt binder modification increased the mixture’s resistance against rutting. BBR test results showed creep stiffness increases of 13.7 and 11.7% for 0.5% GNP and m-value declines of 12.9 and 13.4% for 1% GNP at -12 °C and − 18 °C, respectively, both within PG low-temperature limits and leaving the low-temperature grade unchanged. This study offers valuable insights for policymakers by demonstrating the potential of GNPs to significantly enhance the rheological characteristics of asphalt binders, thereby improving pavement performance.