Khan Inamullah, Khan Zahoor Ahmad, Khan Muhammad Imran, Ali Mujahid, Khan Nasir, Paulraj Manidurai, Avudaiappan Siva
Transportation Engineering Department, National Institute of Transportation, National University of Sciences and Technology, Islamabad, 44000, Pakistan.
Department of Transportation & Geotechnical Engineering, National Institute of Transportation, MCE, National University of Sciences and Technology, Risalpur, Islamabad, 44000, Pakistan.
Sci Rep. 2024 Oct 18;14(1):24419. doi: 10.1038/s41598-024-75679-5.
Bitumen shows visco-elastic behavior, exhibiting both elastic and viscous properties as predicted by dynamic response and phase angle. Modern asphalt bituminous pavements face issues such as early-stage fatigue cracks, rutting, and permanent deformations due to low-temperature cracking, high-temperature deformation, moisture susceptibility, and overloading. These pavement distresses result in the formation of potholes, alligator cracks, and various deformations, which accelerate the need for rehabilitation and maintenance. To address these concerns, this study focused on utilizing Nitrile Butadiene Rubber derived from surgical gloves as an additive in conventional asphalt pavements to assess its effect on stiffness. Nitrile Butadiene Rubber was added in intervals of 2%, 4%, 6%, and 8% to conventional bituminous pavement. The rheological properties, marshall properties, dynamic modulus, and phase angle were evaluated for varying percentages of Nitrile Butadiene Rubber at different temperature, and frequency. The dynamic response was determined using a simple performance tester at four different temperatures (4.4 °C, 21.1 °C, 37.8 °C, and 54.4 °C) and six different frequencies (0.1, 0.5, 1, 5, 10, and 25 Hz). Response surface methodology was employed to establish a relationship between input and output variables and to optimize the amount of Nitrile Butadiene Rubber in the mix based on dynamic modulus and phase angle. The study concluded that adding up to 6% of Nitrile Butadiene Rubber improved Marshall stability, while higher percentages led to reduced stability. A similar trend was observed in the dynamic modulus, which peaked with the addition of 6% Nitrile Butadiene Rubber, regardless of frequency and temperature. The response surface methodology model indicated that coupling the percentage of Nitrile Butadiene Rubber with frequency increased the dynamic modulus at a constant temperature, with the highest value occurring at 4.4 °C. However, the dynamic modulus decreased as the temperature rose for the same combinations of Nitrile Butadiene Rubber percentages and frequencies. Numerical optimization suggested that a maximum of 5.9% Nitrile Butadiene Rubber should be added to achieve the highest dynamic modulus and lowest phase angle.
沥青呈现出粘弹性行为，如动态响应和相角所预测的那样，兼具弹性和粘性特性。现代沥青路面面临着诸如早期疲劳裂缝、车辙以及由于低温开裂、高温变形、水分敏感性和超载导致的永久变形等问题。这些路面病害会导致坑洼、龟裂和各种变形的形成，从而加速了修复和维护的需求。为了解决这些问题，本研究着重于利用源自手术手套的丁腈橡胶作为传统沥青路面的添加剂，以评估其对刚度的影响。丁腈橡胶以2%、4%、6%和8%的间隔添加到传统沥青路面中。针对不同温度和频率下不同百分比的丁腈橡胶，对其流变性能、马歇尔性能、动态模量和相角进行了评估。使用简单性能测试仪在四个不同温度（4.4℃、21.1℃、37.8℃和54.4℃）和六个不同频率（0.1、0.5、1、5、10和25Hz）下测定动态响应。采用响应面方法建立输入和输出变量之间的关系，并基于动态模量和相角优化混合料中丁腈橡胶的用量。研究得出结论，添加高达6%的丁腈橡胶可提高马歇尔稳定性，而更高的百分比会导致稳定性降低。在动态模量方面也观察到类似趋势，无论频率和温度如何，添加6%丁腈橡胶时动态模量达到峰值。响应面方法模型表明，在恒定温度下，将丁腈橡胶百分比与频率相结合可提高动态模量，最高值出现在4.4℃。然而，对于相同的丁腈橡胶百分比和频率组合，随着温度升高动态模量会降低。数值优化表明，应添加最多5.9%的丁腈橡胶以实现最高的动态模量和最低的相角。
