The physical properties determining the strength parameters of bituminous mixtures are strongly influenced by the processes of placement and compaction. This research focused on the assessment of compactibility of mixtures designed for reflective crack relief interlayers (RCRI) which, in most cases, are applied in thin layers. The materials analysed for compactibility in this research included AC – asphalt concrete, AC AF – asphalt concrete “anti-fatigue”,SMA - stone mastic asphalt and SMA-MA - stone mastic asphalt rich in bitumen mastic . The gyratory compactor method was used to determine the compaction slope K, the locking point LP and the compaction densification index CDI. The values of CDI show a substantially greater input of energy required for compaction of high-polymer modified mixtures, as compared to mixtures of the same design, yet containing the 50/70 bitumen. Locking point analysis showed that SMA and SMA-MA mixtures attain 98% relative compaction before reaching the locking point at which the aggregate skeleton starts to resist further compaction. This is quite the opposite as with the AC and AC AF mixtures. Among the tested mixtures the best compaction behaviour was observed in the case of SMA-MA 8 50/70, and this over a wide range of working temperature (100-160°C) and pressures (150kPa, 600kPa). The design of the mixture SMA-MA as an anti-fatigue layer assumes an increase in the content of filler and binder, as compared to conventional SMA. This composition provide a better compaction behaviour as compared to a conventional SMA mixture.
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