Research On The Gradation And Pavement Performance Of Lime Fly-ash Stabilized Gravels Base Course

With the quick development of highway in our country, lime fly-ash stabilizedgravels mixtures have being widely used for base or sub base course at all levelhighway. But in the using of lime fly-ash stabilized gravels base course, there aresome questions as nonstandard construction control, undesirable gradation design,biggish contractility, etc. These questions can finally lead pavement to cracking.First, this paper designed the key sieve passing ratio using the relation graph ofthe relationship between every grain size and their voids in coarse aggregate for theframework type gradation. Dense situation gradation can be confirmed by vibratingtest, and also it’s key sieve passing ratio can be confirmed by the key sieve passingratio of framework type gradation. The dense framework gradation was determinedand adjusted with considering the primary dense situation gradation and constructionworkability. Then, the paper get the grain size groups which need major controlling bysuing grey relational grade theory to analyse the relationship between every grain sizegroup and their volumetric parameters.This paper stated the strength formation mechanism of lime fly-ash stabilizedgravels base course, and figured out another three gradations for mixture design withdesigned gradation. The unconfined compression strength, cleavage strength, dryshrinkage and water stability of these four different gradation mixtures were testedindoor. The test results were analysed with considering the types of these mixturesand the reaction rules of lime fly-ash binder. The results showed that the denseframework structure of designed gradation was well, and the pavement performancewas good enough to satisfy the using requirement.In addition, the use of lime fly-ash stabilized gravels base course can reduce theConsumption of broken stone. This situation can remove the possible environmentaldisruption caused by mining broken stone. Using fly-ash can reduce dust pollutionand farmland occupancy. Not only lime fly-ash stabilized gravels base course hasgood social benefits, it also has good economic benefits. For the low cost and goodroad performance, lime fly-ash stabilized gravels base course being used in ruralhighway which is in a big mileage and capital shortage situation can save large cost.