The study of the relationship between IRI and 3m-straightedge acceptance specification

Due to the expectation of high pavement riding quality by road users, road agencies must enhance their ability to evaluate and manage pavement roughness. As technology has developed, manual and random sampling methods for pavement roughness evaluation have gradually been replaced by fully automated computer systems. Subsequently, the international roughness index (IRI) that is time-stable, transportable, relevant, and valid, was developed and has been generally accepted worldwide. However, some Asian countries still use a 3m-straightedge to evaluate pavement roughness under a fixed sampling interval and determine construction acceptance levels by calculating the standard deviation. To examine the correlation between IRI and standard deviation of the 3 m straightedge, this paper first utilizes power spectral density (PSD) and pavement profile simulation to analyze the measured longitudinal profiles in the long-term pavement performance (LTPP) database. The results demonstrate that the IRI values are positi...