Ameri Mahmoud, Sadeghiavaz Mansour
School of Civil Engineering, Iran University of Science and Technology, Narmak, Tehran, Iran.
Sci Rep. 2024 Oct 5;14(1):23154. doi: 10.1038/s41598-024-73290-2.
Through experimental tests, this paper investigated the effectiveness of microwave healing on asphalt mixtures containing iron powder (IP) filler to improve durability and enhance mechanical properties. The moisture sensitivity of the asphalt mixes with varying iron powder filler contents was measured using the modified Lottman test. For evaluating the asphalt mixture healing ability, two complementary methods were used: the fatigue-based method, derived from the ability of microwave healing of asphalt mixture samples damaged up to 50% level of indirect tensile fatigue (ITF), and the fracture-based method, obtained from the strength recovery rate of broken semi-circular samples by applying consecutive breaking-healing cycles. The results showed that the greater the quantity of iron powder filler in the asphalt sample, the greater the sample's indirect tensile strength and TSR ratio, indicating that IP had a positive effect on moisture sensitivity. The findings also indicated that utilizing iron powder as a filler positively strengthens the fatigue life, increases the toughness, and increases the microwave healing indices (both fatigue and failure approaches). Finally, according to the study results, substituting 70% iron powder as the filler is the most suitable option for improving the mechanical and self-healing characteristics of asphalt mixes.
通过实验测试，本文研究了微波愈合对含铁粉（IP）填料的沥青混合料的有效性，以提高耐久性并增强力学性能。使用改进的洛特曼试验测量了不同铁粉填料含量的沥青混合料的水分敏感性。为了评估沥青混合料的愈合能力，采用了两种互补方法：基于疲劳的方法，源于对间接拉伸疲劳（ITF）损伤达50%水平的沥青混合料样本进行微波愈合的能力；基于断裂的方法，通过对破碎的半圆形样本施加连续的破碎-愈合循环，从其强度恢复率得出。结果表明，沥青样本中铁粉填料的含量越高，样本的间接拉伸强度和TSR比值就越大，这表明铁粉对水分敏感性有积极影响。研究结果还表明，使用铁粉作为填料能积极增强疲劳寿命、提高韧性并增加微波愈合指数（包括疲劳和破坏方法）。最后，根据研究结果，用70%的铁粉替代填料是改善沥青混合料力学和自愈特性的最合适选择。
