Vignali Valeria, Mazzotta Francesco, Sangiorgi Cesare, Simone Andrea, Lantieri Claudio, Dondi Giulio
DICAM Department, University of Bologna, Viale Risorgimento 2, Bologna 40136, Italy.
Materials (Basel). 2016 Oct 18;9(10):842. doi: 10.3390/ma9100842.
In recent years, the use of crumb rubber as modifier or additive within asphalt concretes has allowed obtaining mixtures able to bind high performances to recovery and reuse of discarded tires. To date, the common technologies that permit the reuse of rubber powder are the wet and dry ones. In this paper, a dry-hybrid technology for the production of Stone Mastic Asphalt mixtures is proposed. It allows the use of the rubber powder as filler, replacing part of the limestone one. Fillers are added and mixed with a high workability bitumen, modified with SBS (styrene-butadiene-styrene) polymer and paraffinic wax. The role of rubber powder and limestone filler within the bituminous mastic has been investigated through two different approaches. The first one is a rheological approach, which comprises a macro-scale laboratory analysis and a micro-scale DEM simulation. The second, instead, is a performance approach at high temperatures, which includes Multiple Stress Creep Recovery tests. The obtained results show that the rubber works as filler and it improves rheological characteristics of the polymer modified bitumen. In particular, it increases stiffness and elasticity at high temperatures and it reduces complex modulus at low temperatures.
近年来，在沥青混凝土中使用橡胶粉作为改性剂或添加剂，使得所获得的混合料能够兼具高性能以及废弃轮胎回收再利用的特性。迄今为止，允许橡胶粉再利用的常见技术有湿法和干法。本文提出了一种用于生产沥青玛蹄脂碎石混合料的干混技术。该技术允许将橡胶粉用作填料，替代部分石灰石填料。填料与高工作性的沥青添加并混合，该沥青用苯乙烯-丁二烯-苯乙烯（SBS）聚合物和石蜡改性。通过两种不同的方法研究了橡胶粉和石灰石填料在沥青玛蹄脂中的作用。第一种是流变学方法，包括宏观尺度的实验室分析和微观尺度的离散单元法（DEM）模拟。第二种则是高温性能方法，包括多重应力蠕变恢复试验。所得结果表明，橡胶起到了填料的作用，并且改善了聚合物改性沥青的流变特性。特别是，它提高了高温下的刚度和弹性，并降低了低温下的复数模量。
