Shell Multiphalte bitumen (known as Shell Multigrade bitumen prior to the "Multiphalte" trademark being registered) has been developed as a high quality binder with a reduced susceptibility to change in viscosity with variations in temperature; its rut-resistant properties lie between those of a conventional penetration grade bitumen and those of a polymer-modified bitumen. Laboratory and road trials have been carried out by Shell and by various independent laboratories. Shell Multiphalte bitumen was launched in Australia in 1991, it has been commercially available in parts of Europe since 1992 and in Canada since 1993; it has been successfully used on a wide range of sites. This report details the work carried out by TRL, including the 1987 road trials of rolled asphalt on the A38 at Burton, and reviews that by others. The Burton trial allows direct comparison between Shell Multiphalte bitumen and conventional penetration grade bitumen in rolled asphalt. The various research programmes are sufficiently extensive to allow assessment under the UK Department of Transport (DOT) appraisal procedure for new materials and the results indicate that Shell Multiphalte bitumen has properties that may be usefully employed in appropriate circumstances to enhance the deformation resistance of rolled asphalt surfacings. (A)
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