CHARACTERISATION OF PAVEMENT COMPONENT MATERIALS FOR INCORPORATING VARIATIONS ON SELECTED NATIONAL HIGHWAYS

Abstract

Pavement design technology 15 max_Lng lliereabuu L.Le of elastic and viscoelastic structural analysis and design procedure. Theoretical analysis requires the fundamental material properties, such as modulus of elasticity(E) and Poisson's ratio(11), as the inputs for the formation of the analytical models. A wide variety of techniques are available for characterizing materials(6). It has been always assumed that soils derived from the same parent material and under the same environmental conditions would have same engineering properties. However, even if a perfectly uniform material were tested, some variability in the results would normally occur. The recent recognition of these stochastic or random properties of materials has brought much attention to the use of statistical concept in pavement design. In this study emphasis is laid to know the variability of soil properties, although some tests were also conducted on Aggregates and Bituminous mixes, because material variability is basically due to variation of subgrade soils and its properties. From the statistical analysis, utilizing analysis of var iance techniques, it was found that soil variability is a function of property being measured and type of material being tested. The variability of the soils, as defined by the parameters derived from the laboratory tests, was large. The consequences of such (iv) variation as it pertains to pavement design were considered. This study presents a method, based on economics, for selecting a design value from an array of test data. This analysis indicated that optimum design strength value is generally less than the mean test value, so lower limit of accuracy is taken as design value and that it is dependent upon amount of traffic, environmental conditions, soil variability, compaction variability and anticipated moisture conditions in the completed subgrade.