ANALYSIS OF A CRACKED PAVEMENT BASE LAYER

A study is reported whose objectives were to investigate the effect of the presence of a crack in a treated pavement layer on the stresses and strains induced in the layer by traffic loading and to formulate a procedure for including the effect of the crack during structural pavement design. Prismatic-solid finite-element analysis was used to calculate the stress next to a wide crack, and the ratio of this stress to the stress calculated in an uncracked pavement was taken to quantify the effect of the crack on the stress developed. An increase in stress usually resulted. The study shows that the maximum tensile stress in the treated layer occurs adjacent to the crack at the bottom of the layer and that it acts parallel to the crack. The magnitude of the increase in stress depends on the thickness of the treated layer and the width of the crack, and the maximum increase appears to be 1.4 times. The increase in vertical compressive strain in the subgrade in the vicinity of the crack may be considerable--as much as 14 times--although it is likely to be much less some distance away from the crack. (Author)