Trinidad
Lake Asphalt (TLA, TNA, Epuré) is perhaps the most famous
source of natural bitumen. It occurs as a semi-solid emulsion
of soluble bitumen, mineral matter and other minor constituents.
Mined from the world famous ‘Pitch Lake’ in the
south west of Trinidad, West Indies, it has enjoyed continuous
use in asphalt products for well over 100 years.
TLA is first surface mined from the 100 acre ‘lake’.
The mined Trinidad Lake Asphalt is subjected to a simple refining
process resulting in a material remarkably constant in its
soluble bitumen content of 53 to 55%. The mineral component
is similarly fixed at 36-37%. This mineral constituent works
in combination with the bitumen component to produce the beneficial
properties of TLA.
Until recently TLA has only been available in 240kg drums but
is now available as a granulated product (TNAC 0/8) pre-packed
in easily handled low-melt bags. It can also be supplied blended
with cellulose fibres (NAF501) for addition to SMA mixtures.
Both products are manufactured to DIN EN ISO 9001. TLA will
soon be available in a new pelletised form that will revolutionise
its ease of use. Further details will follow soon.
TLA modified
asphalt materials provide:
| • |
Increased
durability |
| • |
Increased
mixture stability |
| • |
Improved anti-rutting
performance |
| • |
Improved pavement
load carrying |
| • |
Improved whole-life
pavement costs |
| • |
A light coloured,
safer, surface |
| • |
Enhanced skid
resistance properties |
| • |
Enhanced workability
of asphalt mixtures |
| • |
Layer equivalency
benefits |
| • |
Improved fatigue
performance |
| • |
Improved low
temperature cracking characteristics |
| • |
Improved resistance
to high-temperature deformation |
| • |
Improved ability
to display pigments effectively |
| • |
Effective
blending with other additives and bitumens |
|
Typical
Physical Properties
| Softening point |
93-99°C |
| Ash (mineral matter) |
35-39% |
Penetration (25°C, 100gm,
5 sec.) |
0-4 |
| Soluble bitumen (trichloroethylene) |
52-55% |
| Specific Gravity |
1.39-1.44 |
| Maltenes (as % of bitumen) |
63- 66% |
| Asphaltenes (as % of bitumen) |
33-37% |
| Packaging |
low-melt bags / silo
1 tonne big-bags |
| Supply |
1 tonne – bulk shipment
in drums |
TLA has a proven history of successful
asphalt mix modification, backed up by exhaustive test
data from around the globe. TLA has proved to be particularly
effective in heavy duty pavements which must demonstrate
cost-effectiveness and high performance. These applications
include race tracks, container handling facilities, highways,
bridges and airports.
TLA can be stored with no detrimental effect, in marked
contrast to many polymers. TLA can easily be added to any
asphalt mixture,
in any quantity, at any time and mixed at elevated temperatures
with no degradation or loss of performance.
In recent years, TLA has demonstrated that it is particularly
well suited to use in modern thin surfacing systems. It is
routinely used in Stone Mastic Asphalt (SMA), Asphaltic Concrete,
Gussasphalt and Mastic Asphalt materials.
For SMA, replacing 20 to 30% of the binder with TLA is normally
specified, which produces an economical alternative to polymer
modification, with the added benefits of easy storage and addition.
Major projects
where Trinidad Lake Asphalt has been successfully used
include:
| • |
Akashi-Kaikyo
Bridge (Japan) |
| • |
Tsing
Ma Bridge (Hong Kong) |
| • |
Lincoln
and Holland Tunnels (USA) |
| • |
The Nurburgring
Race Circuit (Germany) |
| • |
Seagirt
Marine Terminal (USA) |
| • |
The Mall
(London) |
| • |
Piarco
(Trinidad), Grantley Adams (Barbados) and Copenhagen
(Denmark), and JFK (USA) Airports |
| • |
Major
highways in Japan, Europe, USA and elsewhere |
|
