Abstract: Laboratory trial results of mixing crumb rubber produced from discarded tires with 60/70 pen grade Kuwaiti bitumen are presented on this paper. PG grading and multiple stress creep recovery tests were conducted on Kuwaiti bitumen blended with 15% and 18% crumb rubber at temperatures ranging from 40 to 70 °C. The results from elastic recovery and non-recoverable creep presented optimum performance at 18% rubber content. The optimum rubberized-bitumen mix was next transformed into a pelletized form (PelletPave®), and was used as a partial replacement to the conventional bitumen in the manufacture of continuously graded hot mix asphalts at a number of binder contents. The trialed PelletPave® contents were at 2.5%, 3.0%, and 3.5% by mass of asphalt mix. In this investigation, it was not possible to utilize the results of standard Marshall method of mix design (i.e. volumetric, stability and flow tests) and subsequently additional assessment of mix compactability was carried out using gyratory compactor in order to determine the optimum PelletPave® and total binder contents.
Abstract: Hot Mix Asphalt (HMA) is one of the most
commonest constructed asphalts in Iran and the quality control of
constructed roads with HMA have been always paid due attention by
researchers. The quality control of constructed roads with this
method is being usually carried out by measuring volumetric
parameters of HMA marshall samples. One of the important
parameters that has a critical role in changing these volumetric
parameters is “compaction temperature"; which as a result of its
changing, volumetric parameters of Marshall Samples and
subsequently constructed asphalt is encountered with variations. In
this study, considering the necessity of preservation of the
compaction temperature, the effect of various temperatures on Hot
Mix Asphalt (HMA) samples properties has been evaluated. As well,
to evaluate the effect of this parameter on different grading, two
different grading (Top coat index grading and binder index grading)
have been used and samples were compacted at 5 various
temperatures.