bitumen uses application and its de

1. PART 8 BITUMINOUS
MATERIALS
• 8.1 Introduction
• Definitions
• Safety
• Production
• 8.2 Binders
• 8.3 Bituminous mixtures
• 8.4 Applications

2. Definitions:
• Binder: A material used to hold solid particles together,
i.e. bitumen or tar.
• Bitumen: A heavy fraction from oil distillation
(also occurs as part of natural asphalt).
• Tar: A viscous liquid obtained from distillation of coal
or wood. Rarely used in construction currently in the
UK.
• Asphalt: A mixture of bitumen and mineral filler. Note
that Hot Rolled Asphalt is a road surfacing material.
• Mastic: An adhering asphalt which is placed with
trowelling.
• Macadam: A road construction material with binder and
coarse aggregate. Tarmacadam was the first road
surfacing material.

3. SAFETY
• The flash point is the temperature at which vapour
given off from the surface will burn.
• The fire point is the temperature at which the
binder will burn.
• Water will spread a bitumen fire.
• The materials are generally used at temperatures
high enough to cause severe burns.
• Both the materials and the vapours are potentially
carcinogenic.

4. Melted
Bitumen

5. Bitumen Preparation
Crude
oil
Fractional Distillation
Kerosene Diesel oil Lubricating Base
Petroleum
(parafin) oil Bitumen
Light oil Blending
Penetration Grade
Bitumen
Fluxing Emulsification
in water Oxidation
Cut-back
Bitumen
bitumen Blown Bitumen
Emulsion

6. Tar Preparation

7. PART 8 BITUMINOUS
MATERIALS
• 8.1 Introduction
• 8.2 Binders
• Properties
• Testing
• Binder Mixtures
• 8.3 Bituminous mixtures
• 8.4 Applications

8. Binder Properties
• Adhesion Bituminous materials adhere to
clean dry surfaces.
• Viscosity All bituminous materials are
viscous, i.e. when subject to a long term
load they deform continuously.
• Softening point This is the temperature at
which the binder softens to a pre-
determined point.

9. Durability ….Bitumens are:
• Intrinsically durable, they oxidise, polymerise and
lose light oil components when exposed to air and
heat but all of these processes just make then
harder
• Virtually impermeable if well compacted
• Intrinsically resistant to plant growth
• Softened by high temperature and solvents (often
by fuel spills)

10. Cracking
of thin
surface

11. TESTING Binders
• Sliding plate viscometer In this apparatus a thin film of
binder is sheared between two glass plates and the shearing
force is measured.
• Standard tar viscometer In this test the time taken for a set
volume of tar to flow through an opening at a given
temperature is measured.
• Penetration test For straight bitumens viscosity is normally
measured with a penetration test. A 1mm diameter needle is
loaded with a weight of 100g and the distance it drops into a
bitumen sample in 5 seconds is measured (at 25oC). A
bitumen is referred to as 70 pen if the penetration is 7mm.
• Softening point test To measure the softening point a small
sample is melted, cast in brass ring and cooled and then
progressively re-heated until it deforms (i.e. "flows") by a
given amount.

12. BINDER MIXTURES
• Cutbacks This term is used to describe a mixture
of a binder and a light volatile oil. They are liquid
at low temperatures until the volatile oil
evaporates.. Due to the release of solvents into the
atmosphere they are now rarely used.
• Emulsions When mixed with water binders will
generally settle out. An emulsifier must be added
to give a stable solution. Bitumen paints are made
this way. The water evaporates and the bitumen
remains on the surface. The current types of cold
rolled materials are based on emulsions.

13. Rubberised bitumens
• The viscosity and softening point are increased and
penetration is decreased.
• The elasticity is increased.
• The sensitivity to temperature changes is
decreased.
• The beneficial properties are lost with prolonged
heating.
The increased elasticity and penetration resistance
makes this material ideal for expansion joints and
repairs in roads.

14. PART 8 BITUMINOUS
MATERIALS
• 8.1 Introduction
• 8.2 Binders
• 8.3 Bituminous mixtures
• Components
• Properties
• Testing
• 8.4 Applications

15. The four components of a typical
mix are:
• Coarse aggregate (retained on 2.36mm
sieve)
• Fine aggregate (passing 2.36mm sieve but
retained on 75µ)
• Filler (passing 75µ), may be cement.
• Binder: Bitumen etc.

16. Asphalt Mixing Plant

17. Adding aggregate to a binder has
the following general effects
• The cost is reduced.
• The strength is generally increased.
• If the mix has to be laid hot the aggregate
must also be heated (at considerable cost)
• May fail due to loss of adhesion between
aggregate and binder

18. TESTING Bituminous Mixtures
• Penetration test This test is similar in principle to the
penetration test for binders but on a larger scale. The steel
pin is 6.35mm (0.25") diameter and the load is 10 N/mm2
• Marshall test In this test asphalt mixes are made at several
different binder contents. Cylindrical specimens are loaded
in compression on their curved surfaces. The maximum load
(stability) and the deformation (flow) is recorded.
• Dissolution of binder There are a number of BS tests which
involve dissolution of the binder in solvents. The mix
proportions and the nature of the binder may be determined.
• Percentage refusal density This test is used to measure
compaction in road construction. The density of a core from
the road is compared with the maximum density achievable
using heat and heavy compaction (the refusal density).

19. Marshall Test

20. TESTING Bituminous Mixtures
• Penetration test This test is similar in principle to the
penetration test for binders but on a larger scale. The steel
pin is 6.35mm (0.25") diameter and the load is 10 N/mm2
• Marshall test In this test asphalt mixes are made at several
different binder contents. Cylindrical specimens are loaded
in compression on their curved surfaces. The maximum load
(stability) and the deformation (flow) is recorded.
• Dissolution of binder There are a number of BS tests which
involve dissolution of the binder in solvents. The mix
proportions and the nature of the binder may be determined.
• Percentage refusal density This test is used to measure
compaction in road construction. The density of a core from
the road is compared with the maximum density achievable
using heat and heavy compaction (the refusal density).

21. PART 8 BITUMINOUS
MATERIALS
• 8.1 Introduction
• 8.2 Binders
• 8.3 Bituminous mixtures
• 8.4 Applications

22. Applications
• Roads
• Tanking
• Roofing

23. Road construction types
Wearing course Wearing course
Base course Roadbase
Roadbase
Lower base (crack
Sub-base
resistant)
Sub-base
Subgrade (limestone) Subgrade (limestone)

24. Paving
machine

25. Surfacing materials
• Hot rolled asphalt: Coarse aggregate dispersed in a
mortar composed of sand, filler and bitumen. This is
gap graded.
• Asphaltic concrete: Asphalt in which the aggregate
particles are continuously graded to form an
interlocking structure.
• Surface dressing: Sprayed bitumen binder with stone
chippings rolled on. This is used for repair work.
• Slurry surfacings and micro asphalts: Bitumen
emulsions with selected aggregate combinations. Also
used for repair.
• Stone mastic asphalt: gap graded asphalt composed of
a coarse crushed aggregate skeleton with mastic mortar.

26. Hot Rolled Asphalt Surface

27. Surfacing materials
• Hot rolled asphalt: Coarse aggregate dispersed in a
mortar composed of sand, filler and bitumen. This is
gap graded.
• Asphaltic concrete: Asphalt in which the aggregate
particles are continuously graded to form an
interlocking structure.
• Surface dressing: Sprayed bitumen binder with stone
chippings rolled on. This is used for repair work.
• Slurry surfacings and micro asphalts: Bitumen
emulsions with selected aggregate combinations. Also
used for repair.
• Stone mastic asphalt: gap graded asphalt composed of
a coarse crushed aggregate skeleton with mastic mortar.

28. Failure mechanisms.
• Wearing course:
– Rutting (shear failure)
– Potholes (bond failure)
– loss of skid resistance (viscous flow)
• Lower courses
– Cracking (Fatigue failure)
– Breakdown due to failure of lower courses (e.g.
reflected cracking from dry-lean concrete)

29. Applications
• Roads
• Tanking
• Roofing

30. Tanking a basement
(modern systems use sheet materials)
Asphalt trowelled onto
walls after casting
Base slab cast on layer of
mastic asphalt

31. Applications
• Roads
• Tanking
• Roofing