Determination of insitu flexible moduli of modified pavement materials

Abstract

The aim of this project is to determine the flexible moduli for cement, lime and bituminous modified pavement materials for use in future mechanistic pavement design in North Queensland by back analysis using 'CIRCLY' which is a mechanistic pavement design computer software program. Three trial pavement areas throughout the Far North Queensland area have been monitored over the past years and will be analysed on their performance over this time. The three trial sections chosen are all in extremely wet areas of Far North Queensland's wet tropics, near the small town of Innisfail, which is approximately 100 km's south of Cairns. The rainfall in the Innisfail area has been known to exceed 7 metres for a year. A secondary aim is to attempt to determine a correlation between the actual rutting of three trial road sections by using existing traffic volumes and a 'cumulative damage factor' computed by 'CIRCLY'. This inturn allows a theoretical rut calculation to be compared with the actual rut in the field. The goal is to verify whether the input parameters that are being used in the 'CIRCLY' program are representative of what is actually happening in the field. Presently in Far North Queensland, mechanistic pavement designers are using what are considered to be conservative moduli for the purpose of designing insitumodified pavements. By collecting data and performing back analysis using 'CIRCLY', a more accurate moduli can be determined with the intent to aid in designing a more economical road network. Thus, the overriding aim of this project is to identify different moduli for the different binder-material combinations encounted in Far North Queensland so as to develop a more economical pavement with predictable performance when rehabilitating roads in the region.