Effect of Spatial Variability of Cement-Treated Soil on the Roughness of Airport Pavement

The impacts of spatial variability characteristics of runway subgrade cement-treated soil on the roughness of airport pavements were investigated. The proposed approach aims to calculate potential settlement variations through finite element analyses of an airport section, in a bid to quantify the roughness quality by calculating the Boeing Bump Index (BBI). The deterministic and random finite element analysis results have shown that BBI was strongly influenced by subgrade cement-treated soil variability and the thickness of sand cushion. The existence of random spatial variability of cement- treated soil increases the settlement and as the input coefficient of variation (COV) increases, the settlement increases. Increasing the strength of cement-treated soil is more effective than increasing the thickness of sand cushion on making the value of BBI fall in the acceptable zone.