| TOPICS
Site Update
BS
EN 12591 - Bitumen Viscosity
TRL
- Recycling in Transport Infrastructure
Tack
Coat in the 21st. Century
Motto of the Month
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Introduction
Well, the dark nights are drawing in, here in England,
and I will probably be spending a little more time adding
extra content to existing pages, and producing a few more
pages on new topics, there is still a great deal to cover
in the world of highways maintenance.
Site Update
Regular
visitors may have noticed that the pages have changed a
little, I hope you find them a little more user friendly
and a little less stark in presentation.
I have splashed out and made Bill a little richer by
buying a copy of "Frontpage 2000", as I get
more familiar with its features I hope to be able to
enhance the site still further but still putting content
before "bells and whistles".
BS
EN 12591 - Bitumen Viscosity
BS EN
12591 : Bitumen and bituminous binders - Specifications
for paving grade bitumens
This specification will replace,
BS 3690 : 1989 :
Bitumens for building and civil engineering : Part 1,
Specification for bitumens for road purposes,
in defining the grades of bitumen that will be available
for incorporation in bituminous mixtures from the 1st. of
January 2002, although I seem to recall the introduction
date was meant to be the 1st of May 2001.
However even if the the new date is not met it will
eventually happen so the sooner you make yourself aware
of the changes in specifying bituminous mixtures the
easier the change-over will be.
I also expect the large suppliers of bitumen to the
industry to be providing information on the subject.
However, I am not aware of any press releases from them
at the moment so the change-over may not be as clear cut
as would be desirable, so every engineer/technician
responsible for specifying and purchasing bituminous
material will need to be careful.
The changes are not great for the most commonly used
penetration grades of bitumen, but you should know about
them.
The Quarry Products Association has produced an excellent
one page information sheet on the implications of the
introduction of the new specification, unfortunately I
hear it has been so popular it is currently out of print,
but I understand it will soon ( I could not find it at
the time of writing ) be available for download on their
website, www.qpa.org
.
General information on the current appropriate grades of
bitumen and their use can be found on this site by
visiting the page, Bitumen
Viscosities for Bituminous Materials.
TRL
- Recycling in Transport Infrastructure
The
TRL (Transport Research Laboratory) is presenting a
seminar on the 8th of October at One Great George Street
to launch the guidance document, Recycling in Transport
Infrastructure.
More details on this seminar can be obtained from TRL, or
you could read the very informative, article in the
"Surveyor" of the 6th of September, which
indicates the depth of information that is present in the
guidance document.
I would suggest that for those involved or wish to become
involved in the recycling aspects of highway maintenance
and construction attendance of this seminar and/or a copy
of this document would be extremely beneficial.
A background to some aspects of recycling in highways
maintenance can be found on this site by accessing the
page, Recycling in Highways
Maintenance.
Tack
Coat in the 21st. Century
 
I have only recently come across the
machine photographed above, and I have to say I was
impressed.
Correct tack coating is extremely important both in order
to seal the existing surface against the ingress of water
and to bond the wearing/surface course to the
base/binder course.
It has been developed of course for the large Thin Surfacing contracts on motorways and
trunk roads but I believe contractors are realising
it is cost effective on the smaller jobs also.
It is easily towed behind a reasonable sized vehicle,
which in the case I observed was a large
"pick-up" truck that carried the drums of
bitumen emulsion.
The machine can spray K1-40 or K1-70, and presumably
other suitable emulsions. It is able to heat the emulsion
prior to spraying, which is necessary with a K1-70 to be
able to spray it. However by heating a K1-40 a little it
improves the speed at which it breaks on the road
surface.
But, the main reason I am mentioning it, is that the
quality of the tack coating on the road surface was first
class, with a complete cover over the whole area to be
surfaced. It is obvious a skilled operator is required
with this machine, but given the correct maintenance, it
requires a lot less effort to provide a good job than
with traditional methods, and that means we are likely to
obtain improved tack coating.
Motto of the Month
"Dress
slowly when you are in a hurry."
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