Fuels & Lubricants Magazine

excellent low temperature characteristics
of RmB.
Stable crumb rubber quality and
its particle size distribution are one
of the most important criterion for
rubber bitumen production process.
During crumb rubber production
waste tyres are shredded, fabric and
steel used as reinforcement material
are removed. Used tyres should be
cleaned and impurities have to be
removed before shredding (e.g. clay,
sand and gravel).
The most valuable component of
crumb rubber is the polyisoprene
content. Crumb rubber derived
from tyres of passenger cars contains
10-20% polyisoprene, this value
is around 35-45% in truck tyres.
Further constituents of crumb rubbers
are synthetic rubber (15-45%),
carbon black (25-30%), inorganic
additives (5-15%) and plasticisers (5-
15%) measured according to ASTM
D297-15 standard (16).
Asphalt mechanical tests were
also carried out in the development
phase using different bitumen
products produced in Zala Refinery.
The properties of binders applied
for asphalt tests are summarised in
Table 3. The softening point of RmB
is between the values of other two
commercial products. The highest
penetration ensures good workability
in asphalt mixing and compaction.
RmB has the best breaking point.
Dynamic viscosity of RmB is near to
those value of PmB 25/55-65.
Significantly better results were
measured in asphalt mixtures (Table
4). It has almost the same characteristics
as PmB and far better than
50/70 road bitumen.
It has to be mentioned that fatigue
character of different asphalt types
produced with RmB has been furher
improved last years. Recently this
performance character is on the
same level than that of asphalt mixtures
produced with PmB. Other favourable
properties like traffic noise
reduction (-3.2 dB), better adhesion
Property Test method RmB
50/70 road
bitumen
Softening point, °C EN 1427 59 51 74
Penetration at 25 °C,
0.1mm
EN 1426 65 56 45
Fraass breaking point, °C EN 12593 -24 -12 -14
Dynamic viscosity at 180
°C, mPas
Table 3
EN 13702-2 480 90 410
Requirement RmB
50/70 road
bitumen
PmB
25/55-65
Binder content, % 5.1 5.1 5.1
Permanent deformation/Wheel tracking (EN 12687-22)
Relative deformation, % Max, 5.0 1 3.6 1
Resistance to fatigue (EN 12687-24)
Ehhmax, (N=106), microstrain To be reported 160 143 201
PmB
25/55-65
Asphalt cracking*
Cracking temperature, °C Max, -18.0 -31 -18 -24.8
Table 4: AC-11 type of asphalts produced with different bitumen binders
properties (Fig. 2, tested in 60°C
after 36 hours based on the method
developed by the National Road and
Traffic Research Institute, Sweden)
and stopping distance lowering (-5%
at 50 km/h and -10% at 100 km/h)
were also proved comparing RmB
and 50/70 road bitumen based
asphalts (14).
Based on a recent lifecycle analysis
(17) the complex comparison of asphalt
wearing courses made by RmB
45/80-55 and by normal (unmodified)
road construction bitumen
50/70 were compared. The calculation
resulted + 50% lifetime expectation
and - 29-32% lifetime cost for
the whole lifecycle of the wearing
course.
Among several test road construction
the main road of the Danube
Refinery was also reconstructed in
2012. No fatigue cracks, thermal
cracks and rutting can be observed
after 5 years of heav traffic on the
road (Fig. 3).
In 2015 the Hungarian Standards
Institution published the MSZ
930:2015 standard entitled Bitumen
and bituminous binders. Rubber
modified bitumen. Requirements
(18). This specifies the main quality
requirements of the RmB product
(Table 5).
MOL rubber modified bitumen
won the following awards during the
last years:
• Innovative Product Award of
Institution of Chemical Engineers,
UK (IChemE), 2016,
• Environmental Innovation Award
2014 of Hungarian Ministry of
Agriculture,
• To prove its eco-friendly nature
MOL rubber modified bitumen
gained ECO-label in November,
2014 from Hungarian ECO-labelling
Organisation,
• House of the Hungarian Quality
Award 2013 for MOL rubber
modified bitumen process from
Hungarian Society for Quality,
2013.
Fuels&Lubricants No. 1 OCTOBER 2017 21