Mix design considerations and performance characteristics of foamed bitumen mixtures (FBMs)

The present study focuses on Foamed Bitumen treated Mixes (FBMs). Most of the agencies which use FBMs have their own mix design procedures which are the result of numerous efforts over decades. In spite of all these efforts, Foamed Bitumen application in cold recycling in the United Kingdom suffers from the lack of a standardised mix design procedure. To overcome this, the present research objective was to develop a mix design procedure by identifying critical mix design parameters. The mix design parameters that were optimised were Foamed Bitumen content, mixing water content (MWC), and compaction effort. Special attention was given to the simplest yet crucial mix design consideration of FBMs; curing. The thesis also attempted to simulate what should be expected in terms of the performance of flexible pavements containing FBMs as road base. The present work was also intended to better understand the curing mechanism of FBMs and to lessen the gap between laboratory curing and field evolution of these mixtures. This was achieved by evaluating different curing regimes that are being followed by different agencies and researchers, as well as identifying important parameters that affect curing. In achieving this, a link was established between laboratory mix design and field performance by evaluating applicability of the maturity method. The study also evaluated the applicability of the maturity method as a tool to assess the in-situ characteristic of FBM layers in the pavement. It was found that replacing the time term with an equivalent age term in the maturity function aided in estimating stiffness rather than relative stiffness.


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  • Accession Number: 01596284
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ATRI
  • Created Date: Apr 20 2016 1:55PM