Assessment of non-destructive nuclear and non-nuclear asphalt density testing devices for Australian road construction

Non-nuclear density gauges, also known as Pavement Quality Indicators (PQIs), offer several advantages over widely used destructive test methods and nuclear density gauges (NDGs) for asphalt density measurement. Replacing NDGs with PQIs would simplify regulatory requirements and reduce the cost and complexity of in-situ asphalt density measurement. This is due to the absence of nuclear materials and the ability of PQIs to provide measurements rapidly. However, PQIs have not gained widespread use in Australia due to concerns regarding accuracy. This work assesses the suitability of PQIs for both acceptance and quality control testing by analysing a dataset collected over an extended period and across a wide range of construction sites in Australia. Accuracy was evaluated based on the strength of the relationship between gauge measurements and core density results. Although some evidence supporting the use of PQIs for quality control purposes has been found, their use for acceptance testing remains unwarranted. Recommendations for establishing standard testing methods are provided to encourage wider adoption of PQIs.