Effect Of Heavy Load On Cement Concrete Pavement Performance

Cement concrete pavement often occurs of premature and complex broken slab phenomenon under heavy traffic load.In this article,through field loading test and finite element numerical theory,mainly the dynamic effect of cement concrete pavement under heavy traffic load and the impact of asphalt damping function interlayer on the dynamic performance of cement concrete pavement are studied.Specific research work and results are as follows:Firstly,through the field loading test,to obtain the actual response of pavement slab under vehicle static and dynamic loads.The analysis showed,the response ofslab under static load is symmetrical and static,and the dynamic response of the pavement has the tension and pressure fluctuation alternating response process,which has the characteristics of process,oscillation,speed and frequency.Simulation the mechanical behavior of pavement slab under static and dynamic load by 3-D finite element method,the difference and production mechanism of the static and dynamic response are studied.The anslysis showed,the difference mechanism of static and dynamic is mainly due to the effect of energy propagation,reflection,and superposition in the slab under dynamic load.Comparative the effective effect and fatigue life of pavement under the moving constant load and the random load by numerical analysis.The analysis showed,overestimate the fatigue life of pavement by moving constant load simulation of vehicle load.The random load is closer to the actual vehicle load,the analysis law is closer to the test results.Recommend the use of random load and rain flow counting method of the dynamic effect and fatigue life of the pavement.The sensitivity analysis of parameters is anslyzed based on dynamic finite element.The study found that,the dynamic response occur superposition between the shaft due to multi axis traffic load,and the number of axle,the superposition effect is more obvious.With the increasing number of axles,the difference of the dynamic analysis theory and the static theory is increasing The worst loading postion of pavement slab is closing to the transverse joints edge of the slab.The response of speed on the dynamic response of the slab about the impact of axle load and smoothness.With the increase of speed,the dynamic strain of pavement decreases under constant load.With the increase of speed,the response of pavement first increases and then decreases under the light traffic random load;the fluctuation trend under the heavy traffic random load.Analysts believe there is resonance effect.The dynamic stress peak is linear growth with the increase of axle load pavement.The dynamic characteristics of cement concrete pavement with asphalt function interlayer is analyzed by the finite element method.The research shows,asphalt functional interlayer has significant shock absorption and energy dissipation under dynamic loads,in addition,which can reduces the damage produced by overloading.Put forward the "allowable overload rate" to normaliz comprehensive benefit evaluation indexes,which is used to evaluate the effect of dynamic load and the benefit of asphalt function interlayer.Results showed that,the effect of dynamic load is significant.The impact coefficient cannot express the detailed action characteristic.asphalt function interlayer has a significant benefit to extend the fatigue life of pavement.Based on the above research study,provide the theoretical support for the design of cement concrete pavement under heavy load.