LOADMAN AND BENKELMAN BEAM DEFLECTION STUDIES ON IDENTIFIED ROAD SECTIONS

Abstract

Various types of failures in the pavements range from minor and localized to major distresses. The causes of failures may be due to error in handling (i.e. human) and material as well as inadequate thickness. The maintenance operation and design activities in respect of all types of roads and highways involve the assessment of road condition, diagnosis of the problem and adopting the most appropriate strategy. It is essential that the pavements have adequate stability to withstand the designed traffic loads under prevailing climatic and environmental conditions. Pavement evaluation is to be undertaken for this purpose from time to time which would assess the extent up-to which the pavement fulfils the intended requirement and facilitate the preventive or maintenance actions. The assessment of pavement systems may be classified in to two groups namely functional evaluation and structural evaluation. The various equipments for the pavement evaluation ranges from conventional equipments like Straight Edge,. Benkelman Beam to modem equipments like Dipstick (Auto Read Road Profiler) and Loadman (Portable Falling Weight Deflectometer). All the equipments have some peculiar characteristics and found suitable for particular conditions. This dissertation deliberates the use of Loadman and Benkelman Beam for the measurement of structural condition (Deflection) and develop a relationship between them with a view to facilitate quick deflection measurement with much lesser manpower, without causing inconvenience to traffic movements especially on the urban road sections and on all other road sections carrying heavy to very heavy traffic volume. The linear relationship between Loadman and Benkelman Beam deflection is recommended based on the analysis of results by which the Benkelman Beam deflection value can be obtained after using the measured values of Loadman deflection at each test point. Using the values of Benkelman Beam deflection and the procedure given in IRC: 81-1997, the overlay thickness can be worked out for strengthening of flexible pavements.