Highway materials and tests

Highway Materials: Desirable Properties, Testing Procedures, Standards, and standard values relating to Soil, Stone Aggregates, Bitumen and Tar, fly- ash/pond-ash. Role of filler in Bituminous mix, materials of filler.
Specifications of DLC and PQC for rigid pavement

1. Presented by:
Mukul Nama
Assistant Professor
Department of Civil Engineering

2. Highway construction can be characterized by large right-of-way having length of
considerable amount. Due to this Highway construction constitutes materials that
are needed in large quantum. Depending upon the type of highway pavement,
flexible or rigid the material required for highway construction is decided.
These items of major importance which are used in normal
highway construction
are:
1.Bituminous Materials
2.Soil
3.Aggregates
4.Portland Cement Concrete
5.Admixtures
6.Pavement Marking Materials
7.Structural Steel

3. Bituminous material, or bitumen in the form of asphalt, is one of
the major highway construction materials used.
Asphalt is normally a residue product from the distillation of crude
oil and, as refined, is a heavy, viscous material that is semisolid at
normal atmospheric temperatures.
By controlled processing or blending desired viscosity and
hardness
characteristics can be produced.
 This product is called asphalt cement and is also known as paving
grade or penetration grade asphalt.
 Bituminous Materials, of the Highway Materials Manual contains
the test procedures, sampling requirements, and test equipments.
Bituminous Materials

4. Soils
Major works of man since the beginning of time have depended on
the use of soils.
Not only does soil form the foundation, or supporting surface for
buildings, bridges, roadways and culverts, but it is the most
common constituent, in the form of aggregate.
Soils are the most basic abundant material in highway engineering
and as such, are well characterized by the expression "common as
dirt."
The steps taken to prepare foundations manipulate and transport soils
and prepare them for use as aggregates accounts for well over 70
percent of the total cost of construction for a normal highway project.

5. •The surface, base, and sub base of pavements consist of aggregates
or a mixture of aggregates with cement and water (Portland cement
concrete) or a bituminous material (bituminous concrete).
•The strength properties of a layer are a function of both the quality
and the proportions of ingredients.
•Aggregates are hard, durable, mineral materials obtained by mining
or quarrying operations of deposits of sand, gravel, talus or ledges,
and may be defined as "granular material of mineral composition

Aggregates

6. Portland cement concrete is a mixture of portland cement, water,
air, sand and gravel or crushed stone.
It is formed when the cement and water (paste) combine
chemically and binds the entire mixture into a rock-like mass.
It may be thought of as a two component material; paste and
aggregate.
The paste is comprised of cement, water, and entrained air.
The aggregate portion is generally composed of sand and gravel and
comprises 70 to 80 percent of the volume of the concrete
Aggregates both fine and course, should be selected for their quality,
strength, durability and resistance to environmental affects.

Portland Cement Concrete

7. Number of additives developed to improve various characteristics
of concrete in both the plastic and hardened states.Other additives
gaining in usage are known as water reducing admixtures and set
retarding admixtures.
Water reducing additive is intended to impart more workability into a
plastic concrete with less water, thereby increasing its strength through a
reduced water/cement ratio.

Set retarding additive is intended to slow the setting characteristics of the
mix and thereby allowing more time for placing and finishing
Admixtures

8. Pavement Marking Materials
 Pavement markings have important functions in providing guidance
and information to drivers.
 Pavement markings convey important information to drivers without
diverting their attention from the road.
 In some cases they supplement regulations or warnings given by
other devices.In other cases they are used alone and produce results that
cannot be obtained by any other device.
 Many materials can be used for pavement marking. The choice
depends on cost, durability, reflectivity, pavement surface, and drying
time.

9. These are Pavement Marking Materials, Paint,Water-based paint,
applied either cold or hot, is the most commonly used pavement
marking. It is low cost with a short drying time, but its visibility on
wet nights is just moderate.
Thermoplastics
These pavement-marking materials are made of thermoplastic heated to
about 400° F and spread onto the pavement surface
Epoxy
Also applied as a liquid with special equipment, epoxy has good
visibility and reflectivity, and cost is moderate. Markings remains 3 to 4
years.

10. Moisture Condition Value (MCV) Test
California Bearing Ration (CBR) Test
Dynamic Cone Penetrometer
Ground Penetrating Radar (GPR)
Penetration Test on Bitumen:
Softening Point Test on Bitumen
Los Angles Abrasion Value Test
Flakiness Index Test

11. The California bearing ratio (CBR) is a penetration test for evaluation of
the mechanical strength of natural ground, subgrades and basecourses
beneath new carriageway construction.
Subgrade soil is the integral part of the road pavement structure which
provides support to the pavement. The subgrade and its different properties
are very much important in the pavement design structure.
The major function of the subgrade is to provide the support to the
pavement against traffic loading and for this the subgrade should possess
sufficient stability under adverse climate and heavy loading conditions.
The strength of a soil or subgrade can be determined by using a test
known as California Bearing Ratio Test which was developed in
California in the year 1930's and it is way to determine the standard soil
properties such as density

12. A subgrade characteristics mainly depends on the following three factors
such as,
Load bearing capacity: The subgrade resists loads which are transmitted
from the pavement structure. Various factors such as degree of
compaction, moisture content, and nature of soil affect the load bearing
capacity of soil. A subgrade without excessive deformation sustain heavy
loading is considered good.
Moisture content: Properties such as load bearing capacity, shrinkage and
swelling etc. are mostly affected by the variation of moisture content.
Various things such as drainage, groundwater table elevation, infiltration,
or pavement porosity etc. Influence the moisture content. Highly wet
subgrades deform more under loading..
Sub-Grade performance

13. Shrinkage or swelling mainly depends on moisture content. Additionally,
in frost conditions (in northern climate) soils with excessive fine content
may be susceptible to frost heave.
Shrinkage, swelling and frost heave are the factors whose tendency is to
deform and crack any pavement structure construed over them.
The desirable properties of sub grade soil as a highway material are
Withstand capability (Stability)
Ease of compaction.
Strength permanency
Low change in volume during adverse conditions of weather
and ground water table.
Superior drainage
Incompressibility
Shrinkage and/or swelling:

15. Aggregate plays an important role in pavement construction.
Aggregates influence, to a great extent, the load transfer
capability of pavements, following tests are carried out:
Crushing test
Abrasion test
Impact test
Soundness test
Specific gravity and water absorption test
Bitumen adhesion test

16. Crushing Test is used to determine the crushing strength of
aggregates. The aggregate crushing value provides a relative
measure of resistance to crushing under gradually applied crushing
load
CRUSHING TEST

17. ABRASION TEST
Abrasion test is carried out to
test the hardness property of
aggregates and to decide
whether they are suitable for
different pavement
construction works. Los
Angeles abrasion test is a
preferred one for carrying out
the hardness property and has
been standardized in India

18. IMPACT TEST
The aggregate impact test is carried out to evaluate the resistance to impact of
aggregates. Aggregates passing 12.5 mm sieve and retained on 10 mm sieve is
filled in a cylindrical steel cup of internal dia 10.2 mm and depth 5 cm which is
attached to a metal base of impact testing machine.
The material is filled in 3 layers where each layer is tamped for 25 numbers of
blows. Metal hammer of weight 13.5 to 14 Kg is arranged to drop with a free fall
of 38.0 cm by vertical guides and the test specimen is subjected to 15 numbers of
blows.
The crushed aggregate is allowed to pass through 2.36 mm IS sieve. And the
impact value is measured as percentage of aggregates passing sieve
(W2) to the total weight of the sample (W1).
Aggregate impact value = (W1/W2)*100

20. Soundness test is intended to study the resistance of aggregates to
weathering action, by conducting accelerated weathering test cycles. The
Porous aggregates subjected to freezing and thawing is likely to
disintegrate prematurely. To ascertain the durability of such aggregates, they
are subjected to an accelerated soundness test
Aggregates of specified size are subjected to cycles of alternate wetting in
a saturated solution of either sodium sulphate or magnesium sulphate for
16 – 18 hours and then dried in oven at 105 to 110
0
C to a constant weight.
After five cycles, the loss in weight of aggregates is determined by sieving
out all undersized particles and weighing.
The loss in weight should not exceed 12 percent when tested with
sodium sulphate and 18 percent with magnesium sulphate
solution.

21. The specific gravity and water absorption of aggregates are important
properties that are required for the design of concrete and bituminous
mixes. The specific gravity of a solid is the ratio of its mass to that of an
equal volume of distilled water at a specified temperature.
Water Absorption: The difference between the apparent and bulk
specific gravities is nothing but the water permeable voids of the
aggregates. We can measure the volume of such voids by weighing the
aggregates dry and in a saturated surface dry condition, with all
permeable voids filled with water. The difference of the above two is M
W.
 M
W is the weight of dry aggregates minus weight of aggregates
saturated surface dry condition. Thus,
Water Absorption = (M
W/M
D)*100

22. Bitumen adheres well to all normal types of road aggregates provided they are dry
and free from dust. In the absence of water there is practically no adhesion
problem of bituminous construction.
Adhesion problem occurs when the aggregate is wet and cold. This problem can
be dealt with by removing moisture from the aggregate by drying and increasing
the mixing temperature.
 Further, the presence of water causes stripping of binder from the coated
aggregates. This problem occurs when bitumen mixture is permeable to water.
Several laboratory tests are conducted to arbitrarily determine the adhesion of
bitumen binder to an aggregate in the presence of water. Static immersion test
is one specified by IRC and is quite simple.
 The principle of the test is by immersing aggregate fully coated with binder in
water maintained at 40
0
C temperature for 24 hours.

23. Penetration test
Ductility test
Softening point test
Specific gravity test
Viscosity test
Flash and Fire point test
Float test
Water content test
Loss on heating test

24. Penetration test
 It measures the hardness or softness of
bitumen by measuring the depth in tenths
of a millimeter to which a standard
loaded needle will penetrate vertically in
5 seconds
It may be noted that penetration
value is largely influenced by any
inaccuracy with regards to pouring
temperature, size of the needle,
weight placed on the needle and the
test temperature.
In hot climates, a lower penetration grade
preferred.

25. DUCTILITY TEST
Ductility is the property of bitumen that permits it to undergo great
deformation or elongation.
Ductility is defined as the distance in cm, to which a standard
sample or briquette of the material will be elongated without
breaking.
 Dimension of the briquette thus formed is exactly 1 cm square.
The bitumen sample is heated and poured in the mould assembly
placed on a plate.
 These samples with moulds are cooled in the air and then in water
bath at 27
0C temperature.

26. The excess bitumen is cut and the surface is leveled using a hot
knife. Then the mould with assembly containing sample is kept in
water bath of the ductility machine for about 90 minutes.
The sides of the moulds are removed, the clips are hooked on the
machine and the machine is operated. The distance up to the point
of breaking of thread is the ductility value which is reported in cm.
The ductility value gets affected by factors such as pouring
temperature, test temperature, rate of pulling etc.
 A minimum ductility value of 75 cm has been specified by the
BIS..

28. SOFTENING POINT TEST
Softening point denotes the temperature at which the bitumen
attains a particular degree of softening under the specified
condition of test.
The test is conducted by using Ring and Ball apparatus. A brass
ring containing test sample of bitumen is suspended in liquid like
water or glycerin at a given temperature.
 A steel ball is placed upon the bitumen sample and the liquid
medium is heated at a rate of 5
0
C per minute. Temperature is noted
when the softened bitumen touches the metal plate which is at a
specified distance below.
Generally, higher softening point indicates lower temperature
susceptibility and is preferred in hot climates.

30. SPECIFIC GRAVITY TEST
The specific gravity of bitumen is defined as the ratio of mass of given
volume of bitumen of known content to the mass of equal volume of
water at 27
0
C.
The specific gravity can be measured using either pycnometer or
preparing a cube specimen of bitumen in semi solid or solid state.
In paving jobs, to classify a binder, density property is of great use. In
most cases bitumen is weighed, but when used with aggregates, the
bitumen is converted to volume using density values.
The density of bitumen is greatly influenced by its chemical
composition. Increase in aromatic type mineral impurities cause an
increase in specific gravity.
The specific gravity of bitumen varies from 0.97 to 1.02.

31. It is desirable that the bitumen contains minimum water content to
prevent foaming of the bitumen when it is heated above the boiling
point of water.
The water in bitumen is determined by mixing known weight of
specimen in a pure petroleum distillate free from water, heating
and distilling of the water.
The weight of the water condensed and collected is expressed as
percentage by weight of the original sample.
The allowable maximum water content should not be more than
0.2% by weight.
WATER CONTENT TEST

32. LOSS ON HEATING TEST
When the bitumen is heated it loses the volatility and gets hardened.
About 50gm of the sample is weighed and heated to a temperature of
163
0C for 5 hours in a specified oven designed for this test.
The sample specimen is weighed again after the heating period and
loss in weight is expressed as percentage by weight of the original
sample.
Bitumen used in pavement mixes should not indicate more than 1%
loss in weight, but for bitumen having penetration values 150-200 up
to 2% loss in weight is allowed.

33. What is Bitumen?
The primary use (70%) of asphalt/bitumen is in road construction, where it is used
as the glue or binder mixed with aggregate particles to create asphalt concrete.
Preparation of the existing base course layer
The existing surface is prepared by removing the pot holes or rust if any. The
irregularities are filled in with premix chippings at least a week before laying
surface course.
If the existing pavement is extremely way, a bituminous leveling course of
adequate thickness is provided to lay a bituminous concrete surface course on a
binder course instead of directly laying it on a WBM.
Application of Tack Coat
It is desirable to lay AC layer over a bituminous base or binder course. A tack
coat of bitumen is applied at 6.0 to 7.5 kg per 10 sq.m area, this quantity may be
increased to 7.5 to 10 kg for non- bituminous base.

34. Preparation and placing of Premix
The premix is prepared in a hot mix plant of a required capacity with the desired
quality control. The bitumen may be heated upto 150 – 177 deg C and the
aggregate temperature should not differ by over 14 deg C from the binder
temperature.
The hot mixed material is collected from the mixture by the transporters, carried to
the location is spread by a mechanical paver at a temperature of 121 to 163 deg C.
the camber and the thickness of the layer are accurately verified. The control of the
temperatures during the mixing and the compaction are of great significance in the
strength of the resulting pavement structure.
Rolling
A mix after it is placed on the base course is thoroughly compacted by rolling at a speed not
more than 5km per hour.

35.  The initial or break down rolling is done by
8 to 12 tonnes roller and the intermediate
rolling is done with a fixed wheel pneumatic
roller of 15 to 30 tonnes having a tyre
pressure of 7kg per sq.cm. the wheels of the
roller are kept damp with water.
The number of passes required depends on
the thickness of the layer. In warm weather
rolling on the next day, helps to increase the
density if the initial rolling was not
adequate. The final rolling or finishing is
done by 8 to 10 tonne tandem roller.

36. The routine checks are carried out at site to ensure the quality of the resulting
pavement mixture and the pavement surface.
Periodical checks are made for,
a) Aggregate grading
b) Grade of bitumen
c) Temperature of aggregate
d) Temperature of paving mix during mixing and compaction.
At least one sample for every 100 tonnes of the mix discharged by the hot mix
plant is collected and tested for above requirements. Marshall tests are also
conducted. For every 100 sq.m of the compacted surface, one test of the field
density is conducted to check whether it is atleast 95% of the density obtained in
the laboratory. The variation in the thickness allowed is 6mm per 4.5m length of
construction.
Quality control of bituminous concrete
construction

37. Cement concrete road construction is one of the types of low
volume road construction. We know that the construction of the
road is mostly dependent upon the factor like amount traffic that is
to be handled by the road after its completion.
 On most of the village roads connecting small villages in the rural
areas of the country, the type of vehicular traffic is quite different
from the traffic on other highways.
 The traffic passing on a road can be categorized into three
categories as light commercial traffics, medium commercial
traffics and heavy commercial traffics, but the frequency of each
class of traffic varies with the road.

38. The materials for the cement concrete
road construction may be divided into
two parts. These are mentioned as
follows:-
Selection of basic component
materials
Mix design and production of
pavement quality concrete(PQC) mix
required to construct the cement
concrete road pavement
Materials for concrete cement road
construction

39. Subgrade preparation involves cleaning, earthwork (excavation or
filling of soil, replacement of weak soil, soil stabilization etc.) and
compaction.
Where the concrete layer is laid directly over the subgrade, the
subgrade is moist at the time concrete is placed. If the subgrade is
dry, water could be sprinkled over the surface before laying any
concrete course, however, care should taken so that soft patches or
water pools are not formed at the surface
Construction of Base/ Sub-base
A base/ sub-base to the concrete pavement provides uniform and
reasonably firm support, prevents mud-pumping , and acts as
capillary cut-off.
Subgrade Preparation

40. Sub-base for concrete pavement could be constituted with brick flat soling,
WBM, granular aggregates, crushed concrete, slag, stabilized soil etc. sub-base
could be of three types with
 (i) Granular material (for example, brick soling with one layer of sand under it,
WBM, well graded granular materials etc.)
(ii) Stabilized soil
 (iii) Semi-rigid material, (for example, lime burnt clay pozzolana concrete, lime
fly-ash concrete, lean cement concrete roller compacted concrete etc.).
Compaction and surface finishing
Concrete is spread evenly and is rodded with suitable equipment such that
formation of honey-combing or voids can be avoided. At the same time, over-
compacting needs to be avoided, which can cause segregation and loss of
entrained air

41. Finished concrete has a smooth
surface; texturing of concrete
surface is done to impart required
skid resistance to the concrete
surface. The texturing is done by
means of wire brushing or
grooving along the transverse
direction. Initial texturing may be
done at the time of construction of
the paver itself. Final texturing is
done no sooner the sheen of the
concrete surface goes off.
Texturing

42. Concrete curing
Curing is a process in which requisite moisture content and
temperature is maintained so that concrete achieves its design
strength through hydration of cement

43. QUALITY CONTROL MEASURES
Study duties responsibilities, Tender specification, standards, codes of practice and
work instruction.
Evolve effective acceptance/rejection procedures for construction materials in
coordination with the project purchase department.
Do proper sampling and testing of steel, cement, concrete, aggregates, water, etc.,
and verify test results in view of standards and work specifications prior to their use
in construction. Also control quality of electrodes to their use in welding.
Set procedures to control quality at the points of storage for raw materials,
mixing and placing of concrete.
Follow the prescribed curing and deshuttering schedules.
Observe procedures to control quality of welded joints of structural steel
members.
Evolve a system to check quality of workmanship in all construction activities.

44. Keep all revised Indian Standards and codes of practice available in QC
laboratory and have them handy during discussion with client/consultant.
Maintain sequence of construction required under any activity.
Discuss QA/QC issues as a separate agenda during site review meetings
with staff.
Observe regular schedule for maintenance, repairs and calibration of plants and
equipments.
Keep spare parts/materials for laboratory equipments weigh batchers, batching
plant, etc., always keep spare vibrators ready at site.
Carry work instruction cards in pocket while supervising/inspecting works.
Regularly maintain the formats prescribed under ISO 9002 Quality assurance
system
Practice sound house keeping methods to achieve saving, safety and quality.

45. Highway Drainage
It’s purpose is to drain rain water from the highway into the
sewerage system. A highway drain is the pipe connecting the
highway gully to the surface water sewer.
A soakaway is a drainage pit covered by a metal cover or sometimes by soil.
Its purpose is to allow rain water from buildings to permeate into the
surrounding subsoil. These are sometimes used to drain the highway
Highway drainage should fulfil the following objectives:
Prevent flooding, ponding and seepage, and keep the carriageway,
cycleway and footway as free of standing water as possible.
Ensure surface water falling on the highway enters the drainage system
or natural watercourse as speedily as possible.
Keep the underlying road structure as dry as possible.

46. Prevent injury or damage caused by hazardous surface water.
Prevent highway surface water flooding adjacent properties.
Prevent blockages in associated highway drainage systems with
consequential flooding.

47. Highway drainage is important from
various view points:
 Excess moisture in soil sub-grade causes instability under the road
surface. The pavement may fail due to sub-grade failure. In some
clayey soil variation in moisture content causes considerable
variation in volume of sub-grade. This sometimes contributes to
pavement failure.
The waves and corrugations formed in case of flexible pavements
also play an important role in pavement failure.
Sustained contact of water with bituminous pavements causes
failure due stripping bitumen from the aggregates like loosening of
some of the bituminous pavement layer and formation of pot holes
The prime cause of failures in rigid pavements by mud pumping
is due to the presence of water in fine sub- grade soil.

48. Well designed and well maintained road drainage is important in
order to:
Minimize the environmental impact of road runoff on the receiving
water environment.
 Ensure the speedy removal of surface water to enhance safety and
minimize disruption to road users.
Maximize the longevity of the road surface and associated
infrastructures.

56. Thank You