Inverted pavement system is an alternate form of pavement when compared to flexible pavement. This pavement system consists of a stabilized layer below an aggregate base with asphalt surfacing. In this study, the stabilized layer has been divided into a cemented base layer and a cemented sub-base layer. This research is aimed at evaluating the potential of a cement stabilized brick-fly ash mixture for the base, and only cement stabilized fly ash (no aggregate) for the sub-base layer of the pavement. Three different cement contents (3%, 6%, and 9%) were selected to find the optimal cement content for the base and sub-base layers of the pavement structure. Once the optimal moisture content for different compositions was ascertained, the strength (compressive and tensile), modulus, and durability parameters were evaluated at the laboratory scale. The optimal quantity of cement for the materials used in both layers for stabilization was determined based on the required strength and durability criteria. The optimal cement content for cement-brick-fly ash mixture used for the base layer of pavement was found to be 6%. Similarly, the optimal cement content for cement-fly ash mixture used for the sub-base layer of pavement was found to be 7%. Finally, the inverted pavement consisting of fly ash-based cemented layers is designed based on design on experiment using a centre composite design of response surface methodology. Eight factors were considered for determining the optimized solution under the constraints of minimum critical strains and the thickness of cement-treated pavement layers.

Contributors: Khan S, Ashish P K, Kannelli V, Hossain K, Tiwari D, Nagabhushana M N, Havanagi V G.