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Old Dixie Highway Roadway Coring Project No. PSL -10-3054 (BG 10.5) 2. Fatigue of the existing pavement: heavier vehicles than anticipated Page 3 Increase in loading from higher traffic volumes and in the original design. Under heavy loads, the aged pavement distresses as one or more longitudinal cracks. Ager repeated loading, the longitudinal cracks connect forming many-sided sharp -angled pieces that develop into block cracking. 3. Inappropriate type of asphalt mixture in the structural/wearing course: The asphalt pavement appears to consist of Superpave SP -9.5 or Type S -III asphalt mix, which failed to provide the required volume stability for the roadway when subjected to the heavy loading; especially from seasonal Citrus trucks. This overloading, in our opinion, has contributed to the rutting in the roadway. 4. Lack of timely maintenance: The existing pavement most likely experienced severe cracking before maintenance rehabilitations were performed in the past. Without timely repairs, the pavement is exposed to more severe service conditions due to (1) the stress concentration under traffic; and (2) water damages and accelerated ageing processes. 5. Reflective Cracking: The multi -lifts of the asphalt pavement section indicated that the existing pavement was overlaid after its initial construction. The depth of the cracking is also an indication of incomplete removal of cracking during the previous rehabilitations, which reflected through the overlay within a couple of years. Pavement Section In our opinion, the thicknesses of pavement components are comparable to, or better than, the typical design for this type of roadway. However, the distressed asphalt pavement has compromised its structural capacities to meet the current traffic loading conditions. Based on its current fair to poor condition, the following table provides an estimated Structural Number (SN) of the existing pavement section. The design Structural Number of the same pavement structure would be 4.34. Type S'or SP"Asplrlf i 5%a 0.20 1.05 Base Rocic (100-LBR)*!11'/a 0.18 2.Q3 Compacted S &Wle -- 0 0 Tonal 3.08 Note: * the "black base" was assumed to have the same structural coefficient with the rock base due to its porous condition. REHABILITATION ALTERNATIVES In summary, the existing pavement exhibits severe and extensive distresses; as a result, the existing pavement structural capacity is significantly reduced with an accelerated deterioration rate. With its unique traffic loading pattern, the pavement needs to be repaired to meet the following criteria. (1) All distresses are repaired and the root causes of the distresses are removed; (2) The structural capacity of the pavement is restored to meet the traffic needs currently as well as throughout its service life with normal maintenance; (3) The repair costs should be economically viable in relation to the expected service life; and (4) Meet all project constraints and special DUNKBLBERCCB