Study On The Road Performance Of Fiber Reinforced Lime-fly Ash Stabilized Crushed Stones Roadbase Material

With the continuous development of our country's national economy, the function and status of the highway transportation in national economy is more and more important. Close till the end of 2005, our country has already built up 4, 0000 kilometers expressway, and the national standard highway mileage is 1,515,800 kilometers. There has already been abundant theory knowledge and practice experience about the semi-rigid roadbase, which has an extensive application in our country's highway construction currently and has made a significant contribution to our country's highway construction.Lime-fly ash stabilized crushed stones is a mixture made of lime and fly ash in a certain proportion, and joined with a certain amount of crushed stones, It is called Two-Ash crushed Stones for short, and is one of the semi-rigid roadbase materials, this kind of material not only has a high strength , a good water stability ,and can attain even exceed the effect of other stability materials used in pavement ,but also makes a reasonable use of the industry discards and residues, lowers cost of construction projects, changes discards to treasures, reduces pollution to the environment, so it has a significant economic meaning and social performance. Lime-fly ash stabilized crushed stones as a kind of semi-rigid materials used for a high grade road pavement, has an almost equivalent important position with the cement stability materials and has been applied more and more widely.The roadbase of expressways built in the province of Jilin are all adopted the structure of lime-fly ash stabilized crushed stones. It hasa delightful applied effect in the process of use, and shows a good performance while used in the road, but also has many problems in the meantime, such as:(1) The tensile strength of this material is lower compared with compressive strength. According to the statistics of experiment data, generally the split-tensile strength of two-ash crushed stones mixture is 1/8-1/10 of the compressive strength, so in the structure design, we usually adopt thicker roadbase to satisfy the request of flexural-tensile strength.(2) The performance of frost-resistant is bad .The former experiments indicate that the remaining strength of two-ash crushed stones with 28 days ages and 10 freeze-thaw cycles is 15%-25% to compare with no frost.(3) The performance of shrinkage crack resistance is bad. This is a common fault of the semi-rigid material .As one of the semi-rigid materials, Two-ash Crushed Stones has a big coefficient of dry shrinkage and temperature shrinkage, which often produces typical dry shrinkage cracks and temperature shrinkage cracks in the engineering.(4) The fatigue durability is bad. The experience of domestic shows that, when the flexural-tensile stress is in the level of 0.6MPa, the number of repeated loading, Ne, is between 104to 105.It is the shortage that mentioned above results in the asphalt pavement with two-ash crushed stones roadbase appear to split, frost thawing breakage, sink and other breakage. Those diseases harm and seriously influenced the usage quality of pavement. How to work out these problems and raise the functional performance of two-ash crushedstones is a topic what road workers have been studying on.The domestic scholars have done a lot of research works on the performance of two-ash crushed stones semi-rigid roadbase material used in road, and have got some foundation on the issue of frost-resistant of this material, but not system, and still need a further research on making sure the design index and assessing method and so on. For two-ash crushed stones semi-rigid roadbase material that used in seasonal frozen region, the character of raw and processed materials, the capability of shrinkage crack resistance, the capability of fatigue resistance and the capability of frost-resistant still need to be carried on a further research .This text carries on a research on performance of the two-ash crushed stones semi-rigid roadbase material used in road in the seasonal frozen region, and the main research contents are as follows:(1) Research on the request of quality of the two-ash crushed stones semi-rigid material in the seasonal frozen region , carrying on a research separately on the request of quality of the lime, fly ash , crushed stones and the gravel;(2) Carrying on an analysis on the performance of the two-ash crushed stones semi-rigid material used in roadbase in the seasonal frozen region, mainly from several aspects of this material ,such as the compressive strength, dry shrinkage performance, fatigue strength ,flexural-tensile strength and flexural-tensile modulus etc;(3) Carrying on an experimental research on the performance of the two-ash crushed stones semi-rigid material mixed with fiber used in roadbase in the seasonal frozen region, mainly from several aspects ofthis material after mixed with fiber, such as the compressive strength, mechanical property of frost thawing, flexural-tensile property , fatigue property and performance of temperature shrinkage etc.