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Torsional braid analysis of bitumen‐liquid rubber mixtures
Author(s) -
Kortschot M.,
Woodhams R. T.
Publication year - 1984
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760240404
Subject(s) - materials science , natural rubber , composite material , glass transition , polybutadiene , asphalt , brittleness , ductility (earth science) , colloid , dispersion (optics) , chemical engineering , polymer , creep , physics , optics , engineering , copolymer
The performance of liquid rubbers as low‐temperature plastcizers for bitumen was evaluated by the torsional braid technique developed by Gillham. The low‐temperature dynamic mechanical properties of bitumen‐liquid rubber mixtures were measured from ambient to −100°C and compared with the corresponding fracture behavior using a modified Fraass test. Microscopic observation of the mixture revealed that the liquid rubber was partially soluble in the bitumen at 23°C and at concentrations greater than 10 percent tended to form colloidal dispersions of rubber particles having mean diameters of approximately 10 μm. The loss tangent maxima shifted to lower temperatures and became less pronounced as the concentration of liquid polybutadiene increased. The colloidal rubber dispersion further contributed to the ductility and reduced the brittle temperature of the bitumen at −30°C at 20 percent liquid rubber concentration. The reduction in the brittle temperature of the bitumen is related to the glass‐transition temperature of the added rubber, those rubbers having, the lowest glass‐transition temperatures being most efficient. Such modifications are necessary to reduce the tendency of asphaltic paving materials to crack in cold climates.