Measuring Pavement Condition Data for a Long-term Pavement Performance Study on New Zealand Roads

Abstract

New Zealand like most countries has "site specific" factors which influence pavement performance, some of which are not well investigated or covered in current pavement deterioration models. Apart from the wide variation in climatic conditions, New Zealand has an extensive roading network which is primarily constructed using an unbound aggregate base with a thin surface treatment layer or chip seal wearing-coarse. This data collection project, now in its thirteenth year, was initiated to obtain condition data specific to the New Zealand network. The project brief specified the measurement of pavement roughness, rutting, and texture, using reference or class1 type measuring instruments, coupled with a detailed visual inspection of each calibration site. The aim being to: Accurately measure pavement condition over a period of years and define performance on the range of conditions found in New Zealand. Provide an accurate data base for subsequent research. The end goal being better roading solutions, more accurate research, improved deterioration models, and cost effective improvements to the New Zealand road network. This paper describes the equipment used and why it was selected. It details the equipment calibration procedures and ways to determine the accuracy of the measuring equipment. It also explains the methodology adopted to collect the pavement condition data, and discusses the difficulties encountered. It clarifies achievable levels of measurement repeatability, something that is not currently well defined, and highlights some unexpected results obtained on the different pavement surfaces encountered. For those countries and road controlling authorities considering Long Term Pavement Performance (LTPP) studies or calibration experiments for pavement deterioration modeling, it is believed that this paper will provide useful information on the equipment needs, calibration, validation, and data collection methodology.