高密度辉绿岩对沥青混合料综合性能影响研究

Study on the Influence of High-Density Diabase Aggregate on the Comprehensive Performance of Asphalt Mixture

摘要: 针对高密度辉绿岩应用争议，依托炉慈、桑龙高速公路，开展了高表观密度3.26 g/cm³辉绿岩集料与普通表观密度2.95 g/cm³辉绿岩集料AC-13C沥青混合料路用性能、经济性以及作桥面铺装时对桥梁恒重的影响研究，分析比较了两种密度辉绿岩岩性。研究表明：两种密度辉绿岩水煮时间为3 min、6 min、10 min、15 min、30 min时，AH-70#和SBS改性沥青对集料的黏附性差别小，属于同一个等级；普通密度辉绿岩沥青混合料浸水残留稳定度比高密度辉绿岩提高了7.5%；70℃温度高密度辉绿岩沥青混合料动稳定度比普通密度辉绿岩高17.44%；4 cm厚AC-13C上面层使用高密度辉绿岩碎石沥青混合料每平米增加成本1.75元、增大桥梁恒载8 kg。结合岩性分析，工程中宜优先选择中等密度(2.7~2.9 g/cm³)的辉绿岩。

Abstract: Regarding the application disputes of high-density diabase, relying on the Lunci and Sanglong Expressways, a study was carried out. The study was conducted on the road performance, economic efficiency, and the impact on bridge dead load when used as bridge deck pavement of AC-13C asphalt mixtures with high apparent density (3.2 g/cm³) diabase aggregate and normal apparent density (2.95 g/cm³) diabase aggregate. The lithological properties of the two density types of diabase were also analyzed and compared. The research shows that when the boiling time of the two types of diabase aggregates is 3 min, 6 min, 10 min, 15 min, and 30 min, the adhesion of AH-70# and SBS-modified asphalt to the aggregates shows little difference and falls within the same grade. The immersion residual stability of the normal-density diabase asphalt mixture is 7.5% higher than that of the high-density diabase mixture. At 70˚C, the dynamic stability of the high-density diabase asphalt mixture is 17.44% higher than that of the normal-density diabase mixture. Using a 4 cm thick AC-13C surface layer with high-density diabase aggregate increases the cost by 1.75 yuan per square meter and adds 8 kg to the bridge dead load. Combined with lithological analysis, diabase with medium density (2.7~2.9 g/cm³) should be preferentially selected in engineering.