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Summary of Pavement Coring Services CR 512 from Rosland Road to U.S. Highway 1 ■ Sebastian, Florida September 16, 2014 • Dunkelberger Project No. HB145025 Table II. Northeast -bound Direction Core Identification No. Core Thickness (in) Base Thickness (in) Subgrade Thickness (in) C-16 4 1 8 9 17.0 C-17 4.4 9.6 12.4 C-18 7.2 11 8 5.0 C-19 5.4 11.6 7 0 C-20 31 149 60 AVERAGE: 4.8 11.4 9.5+ Page 3 The asphalt thickness in the southwest -bound direction averaged 2.8 inches. These cores appear to consist of two lifts, with the surface course approximately 0.75 -inch in thickness and the lower lift about 2 -inches in thickness, on average. As indicated by the core data in Table I above, the asphalt layer in the southwest -bound travel lanes is underlain by an average of about 10.6 inches of coquina base followed by a minimum 10 inches of stabilized subgrade consisting of dark brown slightly clayey or slightly silty sand having clayey nodules. Embankment below the stabilized subgrade was encountered in several borings and consisted of light gray fine sand classified as A-3 per AASHTO designation. The asphalt thickness in the northeast -bound direction averaged 4.8 inches. Though individual lifts are difficult to visually discern, cores identified as C-16 to C-19 appear to have at least four lifts of varying thickness and C-18 may consist of six. Core C-20 has a 1 -inch surface course and a lower course of 2 -inches. Of note, Core C-16 exhibits a fair amount of air voids in a 2 - inch lift below a 0.5 -inch surface course. The core data in the northeast -bound direction (Table II) shows an average base thickness of 11.4 inches. The base component is sandy coquina with the exception sandy limerock in Core C-16. The subgrade consists of at least five inches of light gray fine (non -stabilized) sand to the maximum 2 -foot depth of the hand auger boring. The subgrade is designated as A-3 by the AASHTO method. Photos of the recovered cores are included as an Attachment. Data Analysis In our opinion, the thicknesses of pavement components are comparable to the typical design for this type of roadway. However, the aged and distressed condition of the existing asphalt pavement has compromised its structural capacity to meet the current traffic loading conditions. Based on its current fair to poor condition and in reference to Florida Department of Transportation's, Flexible Pavement Design Manual (2008), the following tables provide an estimated Structural Number (SN) of the existing pavement section for each direction of travel. DUNKBLBBRGBR