The effect of early opening to traffic on fatigue life of concrete pavement
Concrete pavements are subjected to many traffic-load repetitions prior to achievement of their full design strength. The effect of early opening to traffic on the life of Portland cement concrete pavement systems was evaluated using experiments and mathematical model. To quantify the loss of life due to early opening of a rigid pavement system, an appropriate fatigue equation is fundamentally required. A series of laboratory fatigue tests was performed on simply supported beams to develop appropriate fatigue relationships for typical, normal strength Texas paving concrete mixture designs. After completion of the laboratory testing, accelerated fatigue tests on full-scale concrete slabs were performed under constant cyclic loading. The concept of equivalent fatigue life was applied to correct the effect of the different stress ratios between field and laboratory testing. The laboratory beams and full-scale field slabs showed an almost identical fatigue relationship after the correction for the variance of stress ratio. On the basis of Miner’s hypothesis of linear accumulated damage, an analytical model for the numerical simulation for the prediction of the loss of life of a Portland cement concrete pavement due to early opening was developed. The numerical simulations were performed for the various assumptions and considerations for field conditions. The current opening criteria used by the Texas Department of Transportation appear to be reasonable based on the sensitivity analysis results.