西南地区路用石灰岩粗集料矿物组成和物理力学性质的关联性分析

Study on correlation between mineral composition and physical and mechanical properties of limestone coarse aggregate in southwest China

为探究西南地区石灰岩粗集料用于高等级公路抗滑表层的适用性,通过X射线衍射试验、激光粒度仪等对8种典型集料进行矿物组成、颗粒性质分析等,定性表征集料组成与其物理力学性质的关系,并基于灰关联理论量化二者关联性;通过常规路用性能试验和动态摩擦系数试验对石灰岩沥青混合料的路用性能和抗滑性能进行验证,从集料组成与力学特性角度揭示混合料抗滑性能衰变规律。结果表明,方解石作为石灰岩集料的主要矿物成分与其物理力学指标关联性最强,并影响次要组成矿物对性能的增强作用;方解石、石英、长石和黏土矿物的不同构成比例对集料物理力学指标影响较为复杂,但高性能矿物含量较多的集料一般具有较佳的性能;白云石为主的集料相比方解石为主的集料能够提供混合料更优的水稳定性;石灰岩沥青混合料的各项性能均满足规范要求,当地石灰岩集料具有较大的高等级公路抗滑表层应用潜力。

To explore the applicability of limestone coarse aggregate for use in anti-sliding surface on highways in Southwest China,the mineral composition and particle condition,etc.of 8 typical aggregates were analyzed by X-ray diffraction and laser particle sizer,etc..The relationship between the aggregate composition and physical and mechanical properties was characterized,and quantitative analysis of the correlation was carried out based on the grey correlation theory.The pavement performance and anti-sliding performance of the limestone asphalt mixture were tested through traditional tests and dynamic friction coefficient test.The anti-sliding deterioration was revealed from the perspective of composition and mechanical properties of the aggregate.The results show that calcite,as the major mineral component of limestone,is most correlated with its physical and mechanical indexes,and has effect on the performance reinforcement of other minor mineral.The effects of various ratios of calcite,quartz,feldspar and clay minerals on the physical and mechanical indexes of the aggregate are complicated.The aggregate with more high-quality minerals has better performance in general.The aggregate composed of dolomite provides a better moisture susceptibility of mixture compared to the aggregate with calcite.The properties of the limestone asphalt mixture can meet the requirement of the specification,which indicates that the local limestone aggregate has great application potential in the anti-sliding surface of highway.