分档再生法与闪长岩新集料在再生GAC-16混合料制备中的应用研究

Study on the Application of Staged Recycling Method and Diorite Aggregate in the Preparation of GAC-16 Mixture

文中选用辉绿岩和闪长岩两种集料,采用分档再生法制备不同旧料掺量的热再生GAC-16沥青混合料,测试对比其高低温性能、水稳定性、抗疲劳性能,以及动态模量,明确新集料类型与旧料掺量对再生GAC-16混合料性能的影响,并比较分档再生与传统再生混合料的微观形貌与各项性能差异.结果表明:随着旧料掺量增加,再生GAC-16混合料的高温抗车辙性能和动态模量提升,低温抗裂性、水稳定性和抗疲劳性能降低,质量分数为40%旧料掺量的热再生GAC-16混合料的各项路用性能均满足规范需求.闪长岩再生混合料的各项性能略低于辉绿岩再生混合料,但仍满足路用需求,证实了闪长岩集料应用于再生混合料中的可行性.分档再生中旧料中的沥青与新沥青之间的混溶更为充分,混溶沥青与集料之间的粘附状态更好.无论选用辉绿岩或闪长岩新集料,虽然分档再生法对所制备GAC-16混合料动态力学性能的提升作用不明显,但可有效提升所制备GAC-16混合料的高低温性能和水稳定性,验证了分档再生法的可行性与适用性.

Two kinds of aggregates,diabase and diorite,were selected to prepare hot recycled GAC-16 asphalt mixture with different content of old materials by step recycling method,and their high and low temperature performance,water stability,fatigue resistance and dynamic modulus were tested and compared.The influence of new aggregate type and old material content on the properties of recycled GAC-16 mixture was clarified,and the differences of micro-morphology and properties between graded recycled mixture and traditional recycled mixture were compared.The results show that with the increase of the content of old materials,the high-temperature rutting resistance and dynamic modulus of recycled GAC-16 mixture increase,while the low-temperature crack resistance,water stability and fatigue resistance decrease.The road performance of hot recycled GAC-16 mixture with 40%old materials content meets the requirements of the specification.The performance of diorite recycled mixture is slightly lower than that of diabase recycled mixture,but it still meets the road demand,which proves the feasibility of diorite aggregate used in recycled mixture.In graded recycling,the asphalt in the old material is more fully miscible with the new asphalt,and the adhesion between the mixed asphalt and the aggregate is better.No matter whether diabase or diorite is selected as new aggregate,the graded recycling method can effectively improve the high and low temperature performance and water stability of GAC-16 mixture,although it has no obvious effect on improving the dynamic mechanical properties of GAC-16 mixture,which verifies the feasibility and applicability of graded recycling method.