Ridge-to-Valley Depth Measured with Road Profiler to Control Micromilled Pavement Textures for Super-Thin Resurfacing on I-95

Abstract

Funding shortages create pavement preservation challenges for state departments of transportation (DOTs). The Georgia DOT developed an innovative micromilling resurfacing method as a cost-effective way to preserve its pavements. The new method can save more than $5 million on an I-95 project of 84 lane miles. To ensure that the micromilled surface texture has a good bond and good runoff capability, the Georgia DOT established a stringent ridge-to-valley-depth (RVD) specification. Preliminary tests were conducted on an I-75 project with a circular track meter and an ultralight inertia profiler, but the RVD was first measured with a laser road profiler for the entire 84 lane miles of the I-95 project. The rough and smooth micromilled pavement surfaces have been studied and compared through an exploration of their statistical characteristics and patterns. Results from four 0.5-mi segments showed that both smooth and rough surface textures revealed normal distributions, although a smooth surface had a slight lognormal distribution. The smooth surface had a mean of about 2.5 mm and a standard deviation of 0.9 mm. The rough surface had a mean of about 4.6 mm and a standard deviation of about 1.1 mm. The cumulative percentage curves for both rough and smooth surface textures showed that the mean RVD value of 3.2 mm could effectively differentiate rough and smooth surfaces. The effects of different base lengths on the RVD were studied, and results showed that a 100-mm base length was adequate to differentiate between smooth and rough surfaces.