Research On Axle Load Conversion And Performance Of Materials Of Subbase Applied To Low-Volume Highway

Based on the traffic volume, traffic axial loads and pavement structures, namely those peculiarities of low volume highway, it is necessary to make an investigation on methods for the axle load conversion which meet the requirements of pavement design of low volume highway in order to study the influence of light duty traffic on feeble asphalt pavement. In addition, emphasis is laid on reducing cost under the precondition that adequate performance can be met. It is feasible to use structural flotsams――brickbat to substitute for gravel to serve as aggregate of the mixtures of subbase. Brickbat has several peculiarities such as high ability of water-absorbing and low rockiness. As a result, it is required to use appropriate methods to be stabilized to meet the requirement of strength and resisting on shrinkage deformation. Based on the basic theory of axle load conversion in combination with investigation datas of axial load, this paper analyzes effects of axial loads on the indexes of pavement structures'design, makes some statistics and summarizes, then educes feasible coefficients and formulas for axle load conversion to supervise the designing of pavement structures. In addition, calculations of pavement thickness are used to validate rationality of those formulas. Lime-soil and lime-flyash-soil are used to stabilize brickbat aggregate. Mechanical performance and shrinkable performance are tested to validate the feasibility that brickbats are used for subbase in low-volume highway. Besides, the rules of stabilization are analyzed to offer reference for the amendments and supplements of criterions. This paper includes:Based on the investigation and analysis of axle loads, practical survey about condition of existing roads and the basic theory of axle load conversion, the second chapter analyzes the influences of axle loads on the indexes of pavement structures'design, and then puts forward feasible indexes and formulas of axle load conversion which are compared with those of current criterions.The third chapter studies mechanical performances of mixtures which are stabilized with brickbat. Different adhesives and different dosages are used to make up several combinations of mixtures to investigate factors which affect strengths of mixtures. The effects of brickbat stabilization are compared with those of gravel stabilization. This paper analyzes correlativity of two different kinds of strengths and moduls.The fourth chapter studies the characteristics of deformation of mixtures which are stabilized with brickbat, then brings forward the laws about dry-shrinkage and temperature- shrinkage in order to provide basis for practical projects.The fifth chapter analyzes pavement structures of low-volume highway, brings forward the requirements for subbase and then analyzes the influences of material parameters and its own crack on the whole pavement structures.The sixth chapter summarizes conclusions of this paper and puts forward the necessity for further research.