Abstract
Current research studies relationship between Falling Weight Deflectometer (FWD) deflection basin parameters and road pavement structural condition indicators, such as fatigue cracking and permanent deformations induced by low bearing capacity of pavement, and pavement equivalent E modulus (Eeq). The primary aim of the research was to develop limit values for deflection basin parameters: surface curvature index (SCI), base damage index (BDI) and base curvature index (BCI). Analyses of data derived from the Estonian Road Databank disproved the hypothesis of relationship between deflection basin parameters and pavement defects or rutting. Deflection basin parameters and back-calculated Eeq were found to be in good correlation. Strong relationships were found between upper layers indicators (SCI and BDI) and Eeq. Relationship between subgrade indicator BCI and Eeq, found in the research, was not very strong. Based on the aforementioned relationships, and the required min equivalent modulus of particular pavement, the equations to determine the limit values of deflection basin parameters for different types of pavements were developed. As the statistical analyses of such extensive database have been done for the first time in Estonia, the determined limit values have to be evaluated in practice and, if needed, corrected.
Highlights
Arraigada et al (2009) have been studied the use of accelerometers to measure pavement deflections due to traffic loads
As the statistical analyses of such extensive database have been done for the first time in Estonia, the determined limit values have to be evaluated in practice and, if needed, corrected
Stronger relationships were found between upper layers indicators (SCI and base damage index (BDI)) and Eeq (Eeq2001-52), as relationship between subgrade indicator base curvature index (BCI) and Eeq2001-52, found in the research, was not very strong
Summary
Arraigada et al (2009) have been studied the use of accelerometers to measure pavement deflections due to traffic loads. While the deflection basin currently used in static methods gives some details of the pavement response under transient loading, the simulations of FWD tests using the dynamic model suggest that the time histories should be included as well for the interpretation of FWD deflection measurements. Grenier and Konrad (2009) presented a robust backcalculation methodology that uses the LevenbergMarquardt iterative minimization technique to identify the value of unknown layer parameters from FWD tests using a dynamic approach based on the spectral element. − Base Curvature Index (BCI) – difference of deflections measured with load cells in the distance 1200 mm (d1200) and 1500 mm (d1500): (d1200 – d1500), which is characterizing condition of the subgrade
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