二次改性沥青的制备及其混合料特性研究

Research on Preparation of Secondary Modified Asphalt and Characteristics of Its Mixture

以聚乙烯(PE)材料为研究对象,在已制备完成的SBS改性沥青中掺入一定量的PE改性剂,对SBS改性沥青进行二次改性,以制备具有更优技术指标的改性沥青,并对二次改性沥青混合料的特性进行了研究。结果表明:随着PE掺加量的增加,改性沥青的软化点逐渐增大,针入度和延度逐渐减小,建议PE的掺量为沥青质量的4%。与SBS改性沥青混合料相比,二次改性沥青混合料的动稳定度明显提高,约为其2倍左右;低温抗裂性能有所降低,但低温破坏应变仍然大于2500με;混合料劈裂强度及冻融劈裂强度皆有所增大,但经过冻融循环后的残留强度比减小。实验结果具有工程实际意义。

Taking the polyethylene （PE） material as the research object, secondary modification is performed on SBS modified asphalt by adding a certain amount of PE modifier in prepared SBS modified asphalt to prepare the modified asphalt with better technical index, and the research is made on the characteristics of secondary modified asphalt mixture. The results show that： with the increase of PE adding amount, the softening point of modified asphalt increases gradually, the needle penetration and ductility decrease gradually, the recommended PE adding amount is 4% of asphalt quality. Comparing with SBS modified asphalt mixture, the dynamic stability of secondary modified asphalt mixture improves obviously, about 2 times; the low - temperature anti - cracking ability decreases, but the low -temperature failure strain is still larger than 2500με; the splitting strength and freeze - thawed splitting strength of mixture increase, but the retained strength ratio after freezing and thawing cycle decreases. The experimental result is with engineering practice meaning.