THE INFLUENCE OF FLY-ASH ON THE PROPERTIES OF ASPHALT CONCRETE --BITUMEN, FLEXIBLE AND DURABLE. 3RD EUROBITUME SYMPOSIUM 1985, THE HAGUE, NETHERLANDS, SEPTEMBER 11-13, 1985

This paper deals with the influence of fly-ash on the properties of hot asphalt mixtures. Specimens have been prepared according to Marshall test to check stability, voids of compacted mixture and deformation (flow value). The specimens were produced from two types of bitumen (80/100 and 40/50). The fly-ash which was used is taken from lignite of ptolemais (Greece). All specimens have been prepared according to the Greek specification a265 for medium traffic. This specification is similar to the astm-d1559. Two types of specimens were prepared either with or without fly-ash which replaces the filler. The results lead to the following remarks: (a) stability -(1) specimens with fly-ash give better values in comparison with those without it. (2) the use of bitumen 40/50 gives also better values. (3) the optimum of bitumen content is 5.5%. (b) voids of compacted mixture -(1) the use of fly-ash gives much higher voids percentage. (2) the use of asphalt 40/50 and 80/100 has no significant influence. (3) the use of fly-ash gives results irrelevant to the Greek specifications. (c) flow value (deformation) -(1) the use of fly-ash gives much higher values of deformation, when compared with the use of filler. (2) the use of bitumen 80/100 gives lower values in comparison with the use of bitumen 40/50. (3) the results are irrelevant to Greek specification (when flying ash is used). In conclusion it must be considered that: (1) there exists a great influence of the fly-ash on the properties of hot asphalt mixtures. (2) the use of fly-ash improves only stability. (3) it is obvious that the use of fly-ash instead of filler results in failure. It is important that further research together with a partial use of fly-ash instead of the complete substitution for filler be performed.(a) for the covering abstract of the symposium see IRRD 815173.