Research On Fatigue Performance Of Roller Compacted Concrete Roadbase Material

At present,the economy of our country is in a rapid development stage,roads,bridges,tunnels,airports and the other constructions are in full swing,and the construction of infrastructure provides strong safeguard for the development of the national economy.However,heavy load and overload have gradually become serious and widespread problem as the traffic volume increasing.Therefore,it's extremely crucial and urgent to extend the road life.As a new kind of base material,especially in the application of composite base,RCC(roller compacted concrete),provides a strong support for pavement,contributing to greatly increase the bearing capacity of the pavement,slow aging and improve the service life of road.So the research on fatigue property of RCC which is one kind of super-stiff concrete,particularly on the rules of the fatigue life,has become an important task of modern road engineering.Firstly,the use of orthogonal design experiment to determine the RCC mix proportion,and then forming beam specimens were a number of different stress than the four-point bending fatigue test under the use of mathematical statistics using two parameter Weibull distribution model the relationship between fatigue life and stress levels were analyzed.The establishment of a double logarithmic fatigue equation under different failure rate;based on the principle injury,analyzes the development of fatigue damage RCC specimens under different stress level S;based on the principle of equivalence of fatigue,study presents RCC axle load conversion formula.This topic research content is to analyze the fatigue of RCC,and the results can be summarized as follows:(1)The forming methods of RCC have been made a comparative study,the appropriate forming methods is chose,and then the best mix proportion of RCC is determined through orthogonal test;(2)The fatigue life of RCC under different stress levels S has been measured and the relevant curve of strain-fatigue life is created;(3)The fatigue life of RCC is in accordance with the two-parameter Weibull distribution and related fatigue life equation is obtained.Double logarithm fatigue equation is establishedunder different failure rates;(4)Under different stress levels S,fatigue damage evolution and crack propagation process of RCC can be divided into three stages,by analyzing fatigue damage situation of each stage,bending fatigue damage of RCC can be explained reasonably;(5)Based on the principle of equivalent fatigue and the equation of RCC for axle load conversion,the corresponding formula is deduced.