Investigating the influence of fine RAP on bituminous mixtures at the mastic scale: viscoelastic analyses and micromechanical modelling

This paper studies the potential effects of Reclaimed Asphalt Pavement (RAP) fine particles on bituminous mixtures by means of a laboratory investigation performed at the mastic scale. Bituminous mastics, characterised by a constant filler to bitumen volume ratio, were prepared by combining virgin filler and virgin bitumen with several dosages of RAP fine particles. The influence of RAP type was evaluated by employing two RAP products supplied by different sources. The rheological behaviour of the mastics was investigated by means of oscillatory tests carried out with a dynamic shear rheometer. The time-temperature superposition principle and the generalised self-consistent scheme (GSCS) micromechanical model were used to explore the role played by RAP at the mastic scale. Results indicate that the adopted experimental and modelling approach allows a proper assessment of the effects of RAP on the linear viscoelastic properties of mastics and of the degree of blending occurring between virgin and RAP binder

EAF Ladle Steel Slag as a Geo-Material: Compaction and Shear Strength Characteristics

İrem Zeynep Yıldırım (MEF Author)##nofulltext##The numerous issues associated with the excess steel slag that is disposed of in landfills every year can be reduced by using it as a geo-material. This paper provides the results of laboratory tests (i.e., sieve, hydrometer, specific gravity, compaction, compaction-particle degradation, and large-scale direct shear with a box size of 30.5 x 30.5 x 20 cm) performed on electric-arc-furnace ladle [EAF(L)] steel slag from a mini-mill in Indiana. Based on standard proctor test results, the maximum dry unit weight values of the EAF(L) steel slag were in the 16.8-to-20 kN/m(3) range at the optimum moisture contents of 11-13%. The results of the large-scale direct shear tests performed on EAF(L) steel slag, compacted at 95-100% relative compaction and sheared with normal stress ranging from 50 to 300 kPa, showed that it has excellent frictional characteristics, with friction angles between 40 and 45 degrees. Based on the results from this study, due to its shear strength characteristics, EAF(L) steel slag has the potential to be utilized as a geo-material to improve the shear strength of various marginal soils.WOS:000437000700012Scopus - Affiliation ID: 60105072Conference Proceedings Citation Index- ScienceProceedings PaperMart2018YÖK - 2017-1