A Critical Comparison of Correlations for Rapid Estimation of Subgrade Stiffness in Pavement Design and Construction
According to pavement design principles, the subgrade or soil layer serving as the foundation for pavement depends on the properties and stiffness of the soil material. The resilient modulus (M<sub>R</sub>) is the absolute measure of the bearing capacity of the subgrade for pavement desi...
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| Format: | Article |
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MDPI AG
2023-03-01
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| Series: | Construction Materials |
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| Online Access: | https://www.mdpi.com/2673-7108/3/1/9 |
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| author | Christina Plati Maria Tsakoumaki |
| author_facet | Christina Plati Maria Tsakoumaki |
| author_sort | Christina Plati |
| collection | DOAJ |
| description | According to pavement design principles, the subgrade or soil layer serving as the foundation for pavement depends on the properties and stiffness of the soil material. The resilient modulus (M<sub>R</sub>) is the absolute measure of the bearing capacity of the subgrade for pavement design. However, due to the complexity of M<sub>R</sub> testing, indirect methods are chosen to determine M<sub>R</sub>. In this context, the CBR test is considered a practical tool for determining the strength of the subgrade, but the use of the correlations of M<sub>R</sub>-CBR has caused great controversy in the scientific community. Nevertheless, such correlations are widely used in practice for pavement design, and the question of their influence on design results is always raised. Therefore, the present study investigates the use and applicability of the M<sub>R</sub>-CBR correlations for the subgrade with respect to the design of flexible pavements, with the aim of optimizing the thickness and bearing capacity of the unbound base/sub-base. Based on the previous debate on the use of M<sub>R</sub>-CBR correlations, this study first investigates the main correlations between M<sub>R</sub> and the CBR index based on a thorough review of the literature. Using the properties of certain medium-grained soils used in practice and the corresponding values of M<sub>R</sub>, estimated by the various M<sub>R</sub>-CBR correlations reported in the international literature, a theoretical pavement design is then carried out on the basis of a sensitivity analysis. A major outcome of the sensitivity analysis is the identification of the most optimal correlation for estimating M<sub>R</sub> in pavement design, while the development of a global M<sub>R</sub>-CBR correlation applicable to most types of soil materials used in pavement construction remains an important topic for future research. |
| first_indexed | 2024-03-11T06:43:07Z |
| format | Article |
| id | doaj.art-c01c38c14e444581a6a84dcbe5a19612 |
| institution | Directory Open Access Journal |
| issn | 2673-7108 |
| language | English |
| last_indexed | 2024-03-11T06:43:07Z |
| publishDate | 2023-03-01 |
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| record_format | Article |
| series | Construction Materials |
| spelling | doaj.art-c01c38c14e444581a6a84dcbe5a196122023-11-17T10:27:22ZengMDPI AGConstruction Materials2673-71082023-03-013112714210.3390/constrmater3010009A Critical Comparison of Correlations for Rapid Estimation of Subgrade Stiffness in Pavement Design and ConstructionChristina Plati0Maria Tsakoumaki1Laboratory of Pavement Engineering, School of Civil Engineering, National Technical University of Athens, GR-15773 Athens, GreeceLaboratory of Pavement Engineering, School of Civil Engineering, National Technical University of Athens, GR-15773 Athens, GreeceAccording to pavement design principles, the subgrade or soil layer serving as the foundation for pavement depends on the properties and stiffness of the soil material. The resilient modulus (M<sub>R</sub>) is the absolute measure of the bearing capacity of the subgrade for pavement design. However, due to the complexity of M<sub>R</sub> testing, indirect methods are chosen to determine M<sub>R</sub>. In this context, the CBR test is considered a practical tool for determining the strength of the subgrade, but the use of the correlations of M<sub>R</sub>-CBR has caused great controversy in the scientific community. Nevertheless, such correlations are widely used in practice for pavement design, and the question of their influence on design results is always raised. Therefore, the present study investigates the use and applicability of the M<sub>R</sub>-CBR correlations for the subgrade with respect to the design of flexible pavements, with the aim of optimizing the thickness and bearing capacity of the unbound base/sub-base. Based on the previous debate on the use of M<sub>R</sub>-CBR correlations, this study first investigates the main correlations between M<sub>R</sub> and the CBR index based on a thorough review of the literature. Using the properties of certain medium-grained soils used in practice and the corresponding values of M<sub>R</sub>, estimated by the various M<sub>R</sub>-CBR correlations reported in the international literature, a theoretical pavement design is then carried out on the basis of a sensitivity analysis. A major outcome of the sensitivity analysis is the identification of the most optimal correlation for estimating M<sub>R</sub> in pavement design, while the development of a global M<sub>R</sub>-CBR correlation applicable to most types of soil materials used in pavement construction remains an important topic for future research.https://www.mdpi.com/2673-7108/3/1/9soil materialssubgrade layerbearing capacityCBRresilient modulusflexible pavement design |
| spellingShingle | Christina Plati Maria Tsakoumaki A Critical Comparison of Correlations for Rapid Estimation of Subgrade Stiffness in Pavement Design and Construction Construction Materials soil materials subgrade layer bearing capacity CBR resilient modulus flexible pavement design |
| title | A Critical Comparison of Correlations for Rapid Estimation of Subgrade Stiffness in Pavement Design and Construction |
| title_full | A Critical Comparison of Correlations for Rapid Estimation of Subgrade Stiffness in Pavement Design and Construction |
| title_fullStr | A Critical Comparison of Correlations for Rapid Estimation of Subgrade Stiffness in Pavement Design and Construction |
| title_full_unstemmed | A Critical Comparison of Correlations for Rapid Estimation of Subgrade Stiffness in Pavement Design and Construction |
| title_short | A Critical Comparison of Correlations for Rapid Estimation of Subgrade Stiffness in Pavement Design and Construction |
| title_sort | critical comparison of correlations for rapid estimation of subgrade stiffness in pavement design and construction |
| topic | soil materials subgrade layer bearing capacity CBR resilient modulus flexible pavement design |
| url | https://www.mdpi.com/2673-7108/3/1/9 |
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