STUDY ON THE EFFECT OF ENVIRONMENTAL FACTORS ON THE DESIGN OF FLEXIBLE PAVEMENTS

By using rational flexible pavement design techniques, the effect of environmental factors on fatigue crack failure in layers of bituminous mixes in different types of structural cross-sections is studied and in accordance with the failure criteria developed by these techniques, the variation in the number of load applications that a given structure is able to withstand when subjected to different weather conditions is determined. This failure criterion assumes a linear elastic behaviour of the materials forming the roadbed and establishes a linear relationship between the logarithm of the horizontal strain caused in the base of the bituminous mix layer by a load being moved over it and the logarithm of the number of times such load is applied until the roadbed shows fatigue failure. The temperature effects are studied and those of its daily seasonal fluctuation on the structural behaviour of various cross-sections determining, for a 5% significance level, the variation in thickness necessary to withstand a 10 exp 4 application of loads by 13 ton axles with the yearly average temperature such section is subject to, the seasonal temperature fluctuation and the bearing strength of the formation. /TRRL/