ANALYSIS OF DATA REQUIRED FOR THE CORRECTION OF SEASONAL VARIATIONS, DEPENDING UPON THE CHANGE IN THE CLIMATIC SEASON OF THE YEAR

As per guidelines under IRC:81-1981 while going through the strengthening of flexible road pavements using Benkelman Beam deflection technique, correction for the seasonal variations, it is always desirable to take deflection measurements during the season and since the pavement deflection is dependent upon change in the climate season of the year, when the pavement is in its weakest condition. In India this period occurs soon after monsoon, deflection measurements should be confined to this period as for as possible. When deflections are measured  during the dry months, they will require a correction factor which is defined as the ratio of the maximum deflection immediately after monsoon to that of minimum deflection in the dry months. The correction factor will depend upon type of surfacing, sub grade soil composition and other factors. Due to large variation in sub grade soil and climatic conditions prevailing in India, it is difficult to give a single value for this factor, It is however recommended, that the clayey sub grade soils the correction factor may be taken as 2 , where as the sandy upgrade it may be taken as 1.2 to 1.3 . For intermediate soil types the value may be interpolated accordingly. From the above it is necessary to record these analysis of data in the proforma suggested by the code for evaluation.