TEST RIG FOR MEASURING DEFORMATION AND STRESS IN FLEXIBLE ROAD PAVEMENTS

VERSUCHSSTAND ZUR MESSUNG VON VERFORMUNGEN UND SPANNUNGEN IN FLEXIBLEN STRASSENKONSTRUKTIONEN

A STUDY IS BEING MADE OF THE BEHAVIOUR OF FLEXIBLE ROAD STRUCTURES UNDER DYNAMIC STRESS, AND THE RESULTS COMPARED WITH VALUES OBTAINED BY MULTI-LAYER THEORY. A TEST ROAD STRUCTURE IS PASSED OVER BY A WHEEL, AND THE HORIZONTAL DEFORMATIONS IN THE BITUMEN-BOUND LAYERS ARE BEING MEASURED BY STRAIN GAUGES AND THE VERTICAL STRESSES IN THE UNBOUND GRAVEL AND SAND LAYERS MEASURED BY RIGID PRESSURE CAPSULES. THE DEPENDENCE OF THE DEFORMATIONS AND STRESSES ON THE TEMPERATURE OF THE ASPHALT AND THE SPEED, LOAD AND TYRE PRESSURE OF THE ROLLING WHEEL IS BEING DETERMINED. MAXIMUM WHEEL LOAD IS 2 TONS AND MAXIMUM SPEED 50 KM/H. INITIAL STUDIES CONCENTRATED ON SPECIFIC STRUCTURES IN WHICH THE SENSORS WERE TESTED AND GENERAL TRENDS IN DEFORMATION AND STRESS WERE ESTABLISHED. THESE SHOWED THE MARKED INFLUENCE OF THE STIFFNESS OF THE BITUMEN-BOUND LAYERS. A FIRST COMPARISON OF THE EXPERIMENTAL VALUES WITH THE VALUES OF THE SHELL COMPUTER PROGRAM IS BASED ON THE FOX AND ACUM ELASTICITY THEORY AND SHOWS EXTENSIVE AGREEMENT, TAKING ACCOUNT OF SCATTER. FUTURE STUDIES ARE INTENDED TO PROVIDE FURTHER EXPERIMENTAL RESULTS WHICH CAN BE USED FOR THE DEVELOPMENT OF DESIGN METHODS. SETTLEMENT MEASUREMENTS ARE ALSO TO BE CARRIED OUT ON THE SURFACE. SUPERSEDES IRRD RESEARCH PROJECT NO 32435.