Parameters Modeling and Probing of Highway Structural Deterioration: Case study of F-209 Segment of Ondo - Ore Pavement, Southwestern Nigeria

The construction of highway route is influenced by geology, geotechnical, topography, and geomorphology the terrain. However, for pavement that failed structurally, a critical investigation required to ascertain cause(s) its failure, so such study can assist during rehabilitation/re-construction phase. Based on this, incessant Ondo – Ore was studied using integrated methods. Electrical resistivity involving four vertical electrical sounding, ten dynamic cone penetration test, three coring trial pits at 1.0 3.0 m offset from edge different chain-age, laboratory geotechnical-geochemical analysis adopting standard procedures. VES characterized geological sequence within alignment be topsoil, subsoil, weathered layer, basement rock. topsoil/subsoil layer which founded sandy clay with less than 200 ohm-m. depths ranged 33.5 45.1 m. recordings are consistent results VES, geochemical analysis, distinctly distinguishing upper 1 into clayey soil (sandy clay, hardpan) laterite, silt-clay-sand mixture. engineering competence road poor, although inactive SC-SM, A-7-5/A-7-6 lateritic type (silica-sesquioxide ratio 1.67). mineralogy illite montmorillonite group. SNG, SN, SNP contributions as subgrade, subbase, base material very low (<1.0). regression models all parameters correlated positively, weak RD DCPI, in-situ CBR MR, CBR; while strong soaked CBR, ER MR. Consequently, based GI values, expected average thickness should range between 191 mm (good segment) 445 (for (avg. 312 mm) far thicker 274 measured along reconnaissance survey. Therefore, it concluded failure result CBR/in-situ values strength coefficient; design across highway. In addition, lack drainage shoulders also causative factor. Hence, need effective roads (to specification) maintenance strategy therefore advocated.