Integrated geotechnical and mineralogical evaluation of the subgrade of some failed pavements along Enugu-Onitsha expressway Southeastern Nigeria
Abstract This research is focused on the constant pavement failure in parts of the Enugu-Onitsha expressway. The failed portions are constructed on the natural subgrade known to be the Shale of Enugu and Mamu formations southeastern Nigeria. Five samples each were obtained from the formations and we...
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2023-08-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-023-41289-w |
| _version_ | 1797576772199383040 |
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| author | Kelechi Paulinus Ukor Ogbonnaya Igwe Obialo Solomon Onwuka Stella Kosi Nzereogu Kelechi Nnaji Eze Pearl Elochukwu Echezona |
| author_facet | Kelechi Paulinus Ukor Ogbonnaya Igwe Obialo Solomon Onwuka Stella Kosi Nzereogu Kelechi Nnaji Eze Pearl Elochukwu Echezona |
| author_sort | Kelechi Paulinus Ukor |
| collection | DOAJ |
| description | Abstract This research is focused on the constant pavement failure in parts of the Enugu-Onitsha expressway. The failed portions are constructed on the natural subgrade known to be the Shale of Enugu and Mamu formations southeastern Nigeria. Five samples each were obtained from the formations and were subjected to geotechnical test, mineralogical analysis, scanning electron microscopy (SEM) and, statistical analysis. The outcome of the geotechnical test revealed that the liquid limits (LL) are of high plasticity with values ranging from 57.69 to 62.61% and 53.57 to 56.24%, plasticity index (PI) values ranging from 20.32 to 24.37% and 13.37 to 15.32%, Slake durability index (SDI) values ranging from 0.55 to 31.8% and 63.4 to 71.6%, for Enugu and Mamu Shales respectively. From the Unconfined compressive strength (UCS) test, the cohesion (C) values ranged from 37.36 to 43.89 kPa and 24.22 to 27.07 kPa, soaked California bearing ratio (CBR) values ranged from 1.03 to 1.22% and 0.90 to 1.60% for Enugu and Mamu Shales, respectively. The test results are not in the range of specification of the Nigerian Federal Ministry of Works and Housing (FMWH) Nigeria standard for pavement construction. X-ray diffraction (XRD) analysis revealed major minerals to be quartz and kaolinite. Moreover, kaolinite disperses and migrates when moist hence geotechnical failure. Images from Scanning electron microscopy revealed the presence of micropores and fractures which can be used as an inference to the geotechnical test results. Statistical analysis of key geotechnical parameters such as SDI, PI, C, and CBR revealed a strong correlation either positively or negatively with each other. The evaluated results pointed out that the underlined natural subgrade is poor for pavement construction, and thus requires improvement. |
| first_indexed | 2024-03-10T21:59:22Z |
| format | Article |
| id | doaj.art-6f7eb15123e84e9e8c264a3a2a362df5 |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-03-10T21:59:22Z |
| publishDate | 2023-08-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-6f7eb15123e84e9e8c264a3a2a362df52023-11-19T13:01:11ZengNature PortfolioScientific Reports2045-23222023-08-0113111610.1038/s41598-023-41289-wIntegrated geotechnical and mineralogical evaluation of the subgrade of some failed pavements along Enugu-Onitsha expressway Southeastern NigeriaKelechi Paulinus Ukor0Ogbonnaya Igwe1Obialo Solomon Onwuka2Stella Kosi Nzereogu3Kelechi Nnaji Eze4Pearl Elochukwu Echezona5Department of Geology, University of NigeriaDepartment of Geology, University of NigeriaDepartment of Geology, University of NigeriaDepartment of Geology, University of NigeriaDepartment of Geology, University of NigeriaDepartment of Geology, University of NigeriaAbstract This research is focused on the constant pavement failure in parts of the Enugu-Onitsha expressway. The failed portions are constructed on the natural subgrade known to be the Shale of Enugu and Mamu formations southeastern Nigeria. Five samples each were obtained from the formations and were subjected to geotechnical test, mineralogical analysis, scanning electron microscopy (SEM) and, statistical analysis. The outcome of the geotechnical test revealed that the liquid limits (LL) are of high plasticity with values ranging from 57.69 to 62.61% and 53.57 to 56.24%, plasticity index (PI) values ranging from 20.32 to 24.37% and 13.37 to 15.32%, Slake durability index (SDI) values ranging from 0.55 to 31.8% and 63.4 to 71.6%, for Enugu and Mamu Shales respectively. From the Unconfined compressive strength (UCS) test, the cohesion (C) values ranged from 37.36 to 43.89 kPa and 24.22 to 27.07 kPa, soaked California bearing ratio (CBR) values ranged from 1.03 to 1.22% and 0.90 to 1.60% for Enugu and Mamu Shales, respectively. The test results are not in the range of specification of the Nigerian Federal Ministry of Works and Housing (FMWH) Nigeria standard for pavement construction. X-ray diffraction (XRD) analysis revealed major minerals to be quartz and kaolinite. Moreover, kaolinite disperses and migrates when moist hence geotechnical failure. Images from Scanning electron microscopy revealed the presence of micropores and fractures which can be used as an inference to the geotechnical test results. Statistical analysis of key geotechnical parameters such as SDI, PI, C, and CBR revealed a strong correlation either positively or negatively with each other. The evaluated results pointed out that the underlined natural subgrade is poor for pavement construction, and thus requires improvement.https://doi.org/10.1038/s41598-023-41289-w |
| spellingShingle | Kelechi Paulinus Ukor Ogbonnaya Igwe Obialo Solomon Onwuka Stella Kosi Nzereogu Kelechi Nnaji Eze Pearl Elochukwu Echezona Integrated geotechnical and mineralogical evaluation of the subgrade of some failed pavements along Enugu-Onitsha expressway Southeastern Nigeria Scientific Reports |
| title | Integrated geotechnical and mineralogical evaluation of the subgrade of some failed pavements along Enugu-Onitsha expressway Southeastern Nigeria |
| title_full | Integrated geotechnical and mineralogical evaluation of the subgrade of some failed pavements along Enugu-Onitsha expressway Southeastern Nigeria |
| title_fullStr | Integrated geotechnical and mineralogical evaluation of the subgrade of some failed pavements along Enugu-Onitsha expressway Southeastern Nigeria |
| title_full_unstemmed | Integrated geotechnical and mineralogical evaluation of the subgrade of some failed pavements along Enugu-Onitsha expressway Southeastern Nigeria |
| title_short | Integrated geotechnical and mineralogical evaluation of the subgrade of some failed pavements along Enugu-Onitsha expressway Southeastern Nigeria |
| title_sort | integrated geotechnical and mineralogical evaluation of the subgrade of some failed pavements along enugu onitsha expressway southeastern nigeria |
| url | https://doi.org/10.1038/s41598-023-41289-w |
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