HOW TO CLASSIFIED THE PAVEMENT CONDITION SURVEY IN THE INFORMATION COLLECTED AND RECORDED IN THE FIELD , BY WAY OF THE SIMPLE MEASUREMENTS INEXPEDIENT TO MODIFY THE OVERLAY DESIGN.

GENERAL PAVEMENT CONDITION SURVEY :-- This phase of operation ,which should precede the actual deflection measurements,consists primarily of visual observations supplimented by simple measurements for rut depth using a 3 metre straight edge  .Based on these , the road should be classified into sections of the equal performance in accordance with the criteria as good for no cracking, rutting less than 10 mm and fair for no cracking or cracking confined to single crack in the wheel track with rutting between 10 mm and 20 mm however in the case of extensive cracking and/or rutting greater than 20 mm the classification of pavement condition must be reported as the poor. As it is inexpedient to modify the overlay design at frequent intervals, it will be preferable if the length of each section is kept minimum of 500 m. During the condition survey , in formation should also be collected about the drainage characteristics, depth of the water table, whether the road is in cut or fill ,changes in soil profile, topography, climatic conditions and other relevant features. Test pits should be dug approximately every 250 to 500 m depending on the uniformity in performance of pavement structure to determine the thickness and composition of the pavement layers .Where it is intended to compare the results with the CBR design  method CBR and other characteristics of the subgrade soil should also be determined on the recommendation made by the IRC :37-1970 . As such the data collected during the condition survey should be recorded as per the performa prescribed and in case of any special or abnormal conditions such as flooding, submergence , previous failure history if any etc must have appropriate vision and report for required operation under the provision made and created for the improvement of the pavement.