Quality Assessment of Road Shoulders using Light Weight Deflectometer and Geogauge

Abstract

Shoulders are an important element of the highways that provide space for vehicles to stop during an emergency. A well-compacted shoulder provides structural firmness to a pavement by transferring overlying traffic loads to the underlying soil stratum. They provide lateral support to the pavement. In recent years, the use of non-destructive testing devices like Geogauge and Light Weight Deflectometer (LWD) has emerged in our country. The main reason behind this is the inbuilt ability of Geogauge and LWD in the fast estimation of the elastic modulus of a shoulder on top of their ease to port, being cost-effective, the capability to give more amounts of data, etc. Thus, there is a need to assess these devices. The main objective of this paper is to develop correlations between the parameter obtained from these non-destructive devices and destructive test parameterslike dry density and CBR. The tests were conducted on thirty-two locations of road shoulders at the city of Patna, India. Geogauge, LWD and sand replacement or sand cone testing were performed at different locations and soil samples were collected for determination of CBR and water content in the laboratory. The result of regression analysis shows that a significant correlation exists between moduli obtained from the devices under investigation and standard test results i.e. dry density and CBR. These developed correlations may be used by the road engineers for assessment of the quality of the shoulders.

Quality Impairments in Flexible Road Pavements

“…Confirmation of such parametric evaluations follows the regressive test between LWD and other density/stiffness methods with better coefficient of determinations (R 2 ). For instance, as outlined in the work of aforementioned researchers investigation of Sandy soil regression-correlation on California bearing ratio (CBR) and E LWD by Dwivedi and Suman [4] gave R 2 values of 0.807 for unsoaked sand (US), 0.805 for soaked (S) sand and dry density 0.77 with the following relationship:…”

“…and may be regarded as are remote and immediate factors leading to failures [3]. Quality Control as a process in road construction ensures conformity of the finished road pavement with required standards [4]. Quality defects are obtainable from the difference in the coefficient of variation of required elasticity modulus (C req v ) from the standard elasticity modulus (C std v ) which is based on deflection patterns of geomaterials composition and dynamic load intensity on pavements.…”

Compaction Quality Inspection and Uniformity Analysis of Soil-Rock Mixed Subgrade

“…The results show that GeoGauge can be used to evaluate the stiffness characteristics of different pavement layers and roadbeds, and the device can also determine the thickness of the measured soil layer and detect the weak points of the compacted soil. Dwivedi [10] analyzed the correlation between GeoGauge detection modulus value, dry density and CBR value. The research shows that there is a good nonlinear relationship between the rebound modulus obtained by the nondestructive testing equipment and the destructive test results, and the model is verified by statistical analysis, which proves that there is a significant correlation between the observed values and the predicted values of various parameters.…”