Study On The Preparation Of Interlocking Fist-like Stone Road Base Course Material

The interlocking fist-like stone road base course material has been put forward,which simplys construction process of the large stone filled with cement stabilized macadam base and promotes interlocking condition and compactedness of coarse aggregate.This technology equips road base with good resistence to heavy load and shrinkage crack,while reduces dependence on labor.The proportion of filling material has been designed with absolute volume method.The influences of filling material proportion on the workability,rheological indexs,mechanical properties,drying shrinkage and microstructure of filling material have been researched.The influence of filling material properties and fist-like stone gradation on compactedness,mechanical properties and drying shrinkage of base material have been researched.The influence of fist-like stone frame on crack development in road base course has been researched.Conclusions are as fellows:The influences of filling material proportion on filling material properties have been explored.The flowability of filling material decreases with the increase of sand volume fraction;increses with the increase of FA content;increases with the increase of W/B ratio;increases with the increase of powder content while powder content is less than 10%and decreases while powder content is higher than 10%;increases with the increase of sucrose dosage.The compressive strength of filling material increases with the increase of sand volume fraction while sand volume fraction is less than 0.58and decreases while sand volume fraction is higher than 0.58;decreases with the increase of FA content while the long-term strength development is promoted;decreases with the increase of W/B ratio;increases with the increase of powder content while powder content is less than 10%and decreases while powder content is higher than 10%;significantly decreases with the increase of sucrose dosage.Drying shrinkage ratio decreases with the increase of sand volume fraction;decreases with the increase of FA content;decreases with the increase of W/B ratio while W/B ratio is less than 0.95 and increases while W/B ratio is higher than 0.95;decreases with the increase of powder content while powder content is less than 15%and increases while powder content is higher than 15%;decreases with the increase of sucrose dosage.The influences of filling material and stone gradation on base material properties have been revealed.The compactness of road base course material increases with the increase of filling material flowability;significantly decreases with the increase of the amount of 31.5mm⁵3mm fist-like stone.The mechanical properties of road base course material is positively correlated to the mechanical properties of filling material;The compressive strength and static elastic modulus increase with the increase of the amount of 31.5mm⁵3mm stone.The drying shrinkage ratio of road base course material is positively correlated to the drying shrinkage ratio of filling material.The interlocking fist-like frame is the most important influence factor to the drying shrinkage of road base course material,which significantly restricts shrinkage of road base course.The interlocking fist-like stone frame complicates the cracking route of road base course,which prevents cracks from continuously development and through road base course.The separation of fist-like stone and harden filling material makes whole road base course between semi-rigid and flexible,which contributes to overcome the intrinsic defects of both semi-rigid road base course and flexible road base course.The optimum design has been determined:sand volume fraction is 0.58,fly ash?FA?content is 40%,water/binder?W/B?ratio is 0.9,stone powder ratio is 10%,fist-stone is composed of 25%31.5mm⁵3mm stones and 75%53mm⁸0mm stones.The road base material compactedness is 92.7%;The compressive strength at 7d,28d and56d are 7.6MPa,15.6MPa and 17.8MPa;The static modulus at 28d is 19.5GPa;The28d dry shrinkage ratio is 216×10^-6.The crack development route becomes more complicated and prevents continuous and single development route of crack.All of design indicater meet the requirement refer to the large stone filled with cement stabilized macadam base.