Flexible Pavement Design over Clay Subgrades

Author(s):

M. Durga Prasad , ANDHRA UNIVERSITY COLLEGE OF ENGINEERING; C. N. V. Satyanarayana Reddy, ANDHRA UNIVERSITY COLLEGE OF ENGINEERING

Keywords:

Gravel, Clay Soils, Black Cotton Soil

Abstract:

Most of the failures in flexible pavement arise from clay subgrades. The causative factors for failure being migrations of capillary water into pavement sections, penetration of subbase material into softened subgrade and volume instability of subgrade. Hence in clay subgrades, it is essential to provide capillary cut off and also the concept of improved subgrade shall be allotted. In expensive clays cushions are to be provided between pavement and subgrade to aboard the Volume changes. In the present study design of flexible pavement are done on Brown clay and Black clay based on CBR method. The designs are also carried out based on the concept of improved subgrade. In Black clay, the designs are also considering sand Blanket course and CNS cushion layers. The cost economics of the different pavement design options are worked out to explain the extra cost of construction involved in all opting CNS cushion/Capillary cut off/improved sub grade in flexible pavement design. The method of improved subgrade involved about 18% and 5% additional cost of construction for flexible pavements in Brown clay and Black clay sub grades respectively.

Other Details:

Manuscript Id	:	IJSTEV5I1035
Published in	:	Volume : 5, Issue : 1
Publication Date	:	01/08/2018
Page(s)	:	89-96

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