Active filler’s effect on in situ performances of bitumen emulsion recycled mixtures

Abstract

This paper address the in situ performance over time of different bitumen emulsion stabilized mixtures blended with different types of fillers (cement, lime and mineral filler), monitored during the first year from construction. Results are part of a more extensive research program aimed to investigate the effects of using lime as active filler in cold recycled mixtures, both with bitumen emulsion and foam bitumen. A specific test track has been designed on a construction road near Florence in order to evaluate the evolution of mixture performance over time. Shortterm bearing capacity has been evaluated by means of LWD (Lightweight tests)after 4 h from compaction while FWD tests have been performed after 24 h,14 days, 28 days and 9 months to monitor the mid-term performances. Up untilmid-2014 tests road was not yet opened to traffic so the mixtures experienced onlyconstruction traffic loads. Results obtained positively support the use of lime as active filler in the bitumen emulsion stabilized material and underline the effect of different blends of fillers in the material behaviour. FWD tests are scheduled to be repeated every 6 months in order to monitor the stiffness evolution of the mixtures and evaluate the nature of traffic damage.