26.5~53 mm大粒径碎石骨架结构性能试验研究

Experimental Study on the Skeleton Structure Performance of 26.5~53 mm Large Stone

粗集料的粒径和级配对骨架密实型路面基层材料的性能有重要影响。为研究26.5~53 mm大粒径碎石的骨架结构性能,选用回弹模量和破碎率两个指标分别评价大粒径碎石骨架结构的承载能力和稳定性。将26.5~31.5 mm、31.5~37.5 mm和37.5~53 mm三档大粒径碎石集料按单粒径、两粒径和三粒径掺配成不同级配,通过振动击实法成型试件并测试其回弹模量和破碎率。试验结果表明:单粒径级配下,试件的回弹模量随粒径增大而提高;两粒径级配下,两档集料含量接近时,试件的回弹模量较高;三粒径级配下,当材料组分改变时,试件的回弹模量变化较小且略高于单粒径级配试件和两粒径级配试件。破碎率试验中,单粒径级配下,碎石粒径增大会稍稍加剧骨架的破碎程度;两粒径和三粒径级配下,各级配试件的破碎率接近且小于单粒径级配试件,且三粒径级配试件的破碎率变化幅度最小。因此,在制备骨架密实型路面基层材料时,推荐以多粒径级配或较大粒径的碎石集料形成骨架。

Particle size and gradation of coarse aggregates have significant effect on performance of skeleton dense cement stabilized macadam.In order to investigate the performance of skeleton structure of 26.5~53 mm large stone,test method of resilience modulus(RM)and crushing rate were optimized for large stone which used to evaluate bearing capacity and stability respectively.Designed various gradation mixture of single particle size,two particle size and three particle size which were composed of 26.5~31.5 mm,31.5~37.5 mm and 37.5~53 mm large stone,and molded specimen by vibration compaction method.Then RM and crushing rate of skeleton structure were tested.The results show that the increase of particle size of single particle specimen will increase the RM.In the two-particle specimen,the RM is higher when the content of the two components is close.In the three-particle specimen,the RM of various proportions of the mixture is comparable.In the crushing rate test,the increase of large stone size under a single particle will slightly increase the crushing degree of skeleton.The crushing rate of two and three-particle is close,and the crushing rate changes have been small when the material composition changes in three-particle mixture.In the pavement base material of skeleton dense structure,it is recommended to use coarse aggregates composed of multiple particle sizes or lager size stone as the skeleton structure.