Our products
Asphalt and asphalt products
Asphalts are dark, soft to rigid petroleum fractions of
colloidal character. They contain asphaltenes, petroleum resins, and the
heaviest petroleum fractions. The easiest way of obtaining asphalts is to
evaporate the volatile petroleum fractions. If this process takes place
spontaneously in nature, we obtain natural asphalts. Asphalts obtained as
distillation residues (usually vacuum residues) during petroleum distillation
are called distillation asphalts. Asphalts can also be obtained during cracking
processes – cracking of asphalt, extraction processes – e.g., propane asphalts,
etc. The properties of asphalts obtained in this way may be further modified
through follow-up processes and technologies such as oxidation, polymer
modification, emulsification, dissolution, etc.
The final products arise either from the individual processes or
they can be prepared by mixing several different products in order to form a
product with the desired properties, from the viewpoint of the asphalts’
rheological properties – asphalts should not crack at low temperatures and
permanent deformation at higher temperatures or long-term load must be low.
Other important characteristics of asphalts are their chemical properties,
chemical composition, and surface characteristics – particularly the
adhesiveness of asphalt to stone aggregate.
The main application of asphalts is in the construction and
maintenance of non-rigid asphalt roads. Three quarters of all produced asphalt
is used in this way. The continuing growth of road transport and the expansion
of road and highway networks require a constant supply of road asphalt.
Probably everybody must have noticed the immense increase in road
transportation in this country since 1990. The figures show that the number of
both passenger cars and trucks has increased by one half over the past ten
years. However, the road system has not witnessed an equal level of
development.
The ever-growing load on the road system increases the
requirements for roadway properties. Investors must decide whether to build
asphalt or cement-concrete roads. Each has its advantages; both types are used
in developed countries with analogous geographical and climatic conditions.
With today’s road asphalt technologies using modified road asphalts, we can
build non-rigid roads able to withstand high loads.
In addition to the standard non-modified asphalts, the
road-asphalts group also includes special non-modified hard asphalts and
asphalts with a high modulus of rigidity. These are used in cast road- and
waterproofing asphalts and in special compacted covers with high moduli of
rigidity. Another group of road asphalts is composed of the so-called modified
asphalts, which are adjusted and modified by suitable polymers to improve the
rheological characteristics of the asphalt bonding agent and to increase the
resistance of the asphalt mixtures to the formation of ruts and frost cracks.
The market offers a diverse range of modified asphalts created
by refineries as well as bonding agents produced by some road builders in their
own modification centres. Bonding agents based on thermoplastic elastomers play
a crucial role. Thanks to the outstanding properties of highly modified road
asphalts, special new technologies have been developed, e.g., elastic
membranes, draining carpets, expansion joints.
To regenerate older road surfaces, so-called cutback asphalt is
used. In this case, road asphalt is softened using a light or medium petroleum
fraction in order to lower its viscosity, to reduce application temperature,
and to achieve a regenerative effect on the aged asphalt road surface. In view
of their negative environmental impact and Class II flammability, the volume of
cutback asphalts is being reduced and their application is directed towards
special regenerative and reparative technologies.
The last type of asphalt bonding agent used in road building are
asphalt emulsions. Today, exclusively cationic-active asphalt emulsions are
used. This is a growing and environmentally advantageous area of
low-temperature construction and maintenance of asphalt roads. Emulsions are
mainly used in road coating and sprayed repairs, for slurry seals, binding
sprays, cold microsurfacing, and cold-mix paving.
To seal asphalt surface cracks as well as joints in tram track
panels, cement-concrete road surfaces and paving stones, and to prevent
penetration of rainwater into bottom layers, various asphalt fillers are used,
with various performance qualities, i.e., ability to seal the joint against
weak, medium or strong temperature dilatations.
Asphalt’s characteristic adhesiveness to surfaces, its
hydrophobic properties and low price predestined it to be a suitable material
for insulating buildings and building parts against the adverse effects of rain
water, pressurised and non-pressurised groundwater, condensed steam, and
humidity. Today, building-insulation asphalts workable at high temperatures
have already made way for a wide range of asphalt insulating products
applicable at low temperatures that mainly serve as semi-finished products for
the manufacture of insulating strips.
Roofing has an important position in waterproofing industry. A
major share of roofing materials today uses insulation made of oxidised or
modified insulating strips. For maintenance, repairs, and roofing of
smaller-scale roofs, either water-soluble asphalt suspensions or asphalt
putties are used, always in combination with bracing fillers. Asphalt paints
are used to coat aged sheet-metal roofs. To achieve better appearance of the
paint, a reddish brown asphalt suspension or reflective painting materials are
used, the reflective layer of which reflects sunrays and reduces temperature of
the roofing by up to approx. 15°C.
To insulate parts of buildings against water, particularly to
insulate foundations and underground areas of buildings against underground
humidity, asphalt materials applicable at low temperatures are used more often
than strip insulation. To ensure good attachment to concrete surfaces,
asphalt-penetrating paints are applied. To paste construction material to
concrete surfaces, asphalt glues based on asphalt-rubber and resin are used.
Asphalt is applied in other industrial fields as well. It is a
very good electrical insulator, its shiny colour is used in the preparation of
glossy black paints, its binding properties are applied in the preparation of
foundry moulds and the preparation of rubber-making mixtures, and it is used as
a lubricant in rolling mills and as a binding agent for stabilising
(solidifying) hazardous waste.
The manufacture of asphalt products in the Czech Republic is
concentrated in refineries; however, their manufacture abroad is sometimes
completely separated from refineries. Asphalt products thus are either refinery
and construction products. Asphalts are also listed among construction products
by current European legislation and, as such, asphalts and asphalt products
must be certified by an authorised person, and their application is subject to
a construction-technical certificate.
česky