The document discusses the use of mineral fillers and dust additives to increase the strength of road pavements by densifying the graded mixture. It describes various types of mineral fillers including finely powdered limestone, slag, hydrated lime, Portland cement, and fly ash. The mineral filler reduces the void content in the mixture. Bituminous materials and asphalt are also discussed as binders used for road construction aggregates. Different types of bituminous binders include cutback asphalt, emulsified asphalt, oxidized asphalt, and road tar. Various tests for evaluating the properties and performance of bituminous binders are outlined.

1. 5-4 Mineral filler
The strength of road pavement will be
increased if dust additives which dense the
graded mixture is added. It is called
mineral filler that the reduces the void
contents in the mixture. This dust additive
is not the ordinary dust that is being found
in our floor or tables.

2. Dust additive is classified into:
1. Finely powdered limestone
2. Slag
3. Hydrated Lime
4. Portland Cement
5. Trap rock dust
6. Fly ash

3. The DPWH Standard Specification relative to mineral filler state that:
“Mineral filler shall consist of finely divided mineral matter such as rock dust, slag
dust, hydrated lime, hydraulic cement, fly ash or other suitable mineral matter. It
shall be free from organic impurities and at the time of use shall be sufficiently dry
to flow freely and shall be essentially free from agglomerations’’
AASHTO M-17 provides that:
Percentage passing by weight shall be as follows:
No. 30(0.66mm) sieve 50
No. 50(0.30mm) sieve 95-100
No. 200(0.075mm) sieve 70-100
AASHTO further stipulates that all mineral other than hydrated lime or Portland
cement, the Plastic Index (PI) value shall be 4 or less.

4. 5-5 BITUMINOUS MATERIAL
Bituminous material or Asphalt in short, is a viscous liquid used as binder for
aggregates in road construction. At normal temperature, asphalt is either
slightly thicker than water or hard but brittle material that breaks under a
hammer blow when cold.
1.) Bituminous material is in liquid from when mixed or combine with liquid
from may be produced either by heating the hard asphalt, by dissolving in
solvent or by emulsifying in water. However, there are bituminous liquid
materials available and ready for use.
2.) The action of asphalt binder depends on its type and the aggregate it is
combined with. The purpose of the asphalt binder is to resist the abrasive
force brought about by heavy traffic.

5. TABLE 5-4 SUGGESTED SPRAYING AND MIXING TEMP. (°C)
FOR BITUMINOUS MATERIALS AND ROAD TARS*+

6. 3.) If road pavement is the open type, consisting
entirely of coarse particles and asphalt, heavy binder is
needed requiring more asphalt. On the other hand, if
aggregates in the pavement contain fine particles,
cohesion will be developed by surface tension in the
thin asphalt film surrounding the fine particles. Hence,
viscous asphalt is required.

7. 5-6 Bituminous Binders
Asphalt cement is used as binder for almost all high types of
bituminous pavement. Asphalt cement is a semi solid hydrocarbon
retained after fuel and lubricating oils are removed from petroleum.
The softest grade used for pavement is the 200-300 penetration. The
60-70 penetration is the hardest type.
Penetration refers to the consistencies of asphalt cement as
describe under AASHTO-T49. It is the distance that a standard needle
penetrates a sample under known conditions of loading time and
temperature. Recently, the procedure used in grading asphalt cement is
the Viscosity Test rather than the Penetration Test. (see ASSHTO M-
226 Specification for Transportation Materials).

8. Cutback or Liquid Asphalt
1.) Liquid asphalt is a petroleum production consisting of asphalt
cement with liquid distillate (diesel, kerosene or gasoline). The less
viscous asphalt contains diluents as little as 15%.
2.) The use of cutback is being frowned for two reasons:
a. It is a usable fuel
b. It is an air pollutant
3.) Cutback or Liquid asphalt is classified into:
a. Slow curing (SC) road soil
b. Medium curing (MC) cutback asphalt
c. Rapid Curing (RC) cutback asphalt

9. Emulsified Asphalt
Emulsified asphalt is a kind of mixture wherein the minute
globules of asphalt disperses in water. Asphalt content ranges from
55%-70% by weight. Emulsion could be applied or mixed at normal
temperature, because when the water content evaporates, the asphalt
remains. It has the following characteristic.
1.) Emulsified asphalt is excellent with wet aggregate because the
water medium carries the asphalt into a superior contact with the
particle surface.
2.) Emulsified asphalt is an alternate to cutback asphalt for energy and
environmental objectives. It is an effective material in coating
electropositive aggregates with high content of silica for having strong
electronegative surface charges.

10. 3.) The Cationic emulsion is very effective on high
siliceous aggregates but may strip from high alkaline that
carry strong positive surface changes.
4.)Rejuvenating Agent is an emulsified petroleum resin
sprayed over the surface of an old asphalt road that changes
to asphaltenes causing the binder to harden and cracks. The
rejuvenating agent sprayed over the pavement and softening
the binder. Too much application however, produces a slick
pavement surface.

11. Oxidized asphalt and Road Tar
Oxidized asphalt is suitable only for roofing and similar applications.
Highway used of oxidized asphalt is limited to water proofing of
structures and filling joints of concrete pavement.
Road tar is a by-product of the distillation process of coal. Tars are
produced from gashouse coal tar, cook even tars and water gas tar.
The AASHTO classification of coal tars includes RT-1 to RT-12 and
RCTB-5 to RTCT-6.
RT-1 is suitable for application as tack of Prime Coat at normal
temperature.

12. 1.) Bituminuos materials shall be either Rapid Curing Cut Back or
Emulsified asphalt.
2.) Tack Coat shall be applied only to dry surface or slight moist. No
Tack Coat shall be applied when the weather is either foggy or rainy.
3.) Immediately prior to the application of Tack Coat, the road surface is
slightly sprayed with water, but not to be saturated
4.) The rate of application of either the Rapid Curing, Cut Back or
Emulsified asphalt is within the range of 0.2 to 0.7 liter per square
meter. Any excess of this specified quantity should be blotted by sand
or removed.
5.) Tack Coat shall be sprayed only as far in advance on the surface
course as will permit it to dry in a tacky condition. Traffic shall be kept
off the Tack Coat until after fully dried.

13. Bitumen-Rubber Mixture
The bitumen rubber mixture for road pavement
was experimented in Holland in the year 1929. It
was adopted in the United Stated in 1947 and
later, in European countries. The assessments of
the road states that:

14. 1.) Very little improvement gained as far as coefficient of friction
on newly laid pavement but expect higher advantages after six
months. The analysis of the Bureau of Public Roads states that:
“An appraisal of the real economic value of the addition of rubber to
asphalt must wait on further observation of the behavior of
experimental pavements under the influence of age, weather and
traffic’’
2.) According to the report, powdered rubber foams added to bitumen
has improved the stability of some but not all.

15. Epoxy Resin as Binders
Epoxy binders are production in a clear, dark, rigid and flexible
form for application to either concrete or asphalt pavement. Hardening
can be attained by mixing the resin and the catalyst hardener prior to
application. The result is called thermosetting. Meaning, it will not
soften under the influence of heat or the action of solvent like water or
petroleum products. The high cost of resin has restricted its use to
bridge surfacing and other special non-skid seal coating surface only.

16. Test for Bituminous Binders
1. Test of consistency is subdivided into:
a. Kinematics Viscosity test AASHTO T-202
b. Saybolt-Fural test AASHTO T-72
c. Engler specific gravity test AASHTO T-54
d. The float test AASHTO T-50
e. Penetration test AASHTO T-49
f. Softening point test AASHTO T-53

17. 2. Test for durability AASHTO T-52
3. Test for solubility AASHTO T-44
4. Distillation test AASHTO T-78
5. Thin film oven test AASHTO T-179
6. Flashpoint AASHTO T-48%79
7. Test for homogeneity of petroleum asphalt AASHTO T-102
8. Special test for Emulation asphalt AASHTO T-59

18. a. Test for demulsibility
b. Test for settlement
c. Sieve test
d. Cement mixing test
e. Particle charge and PH tests
f. Miscibility and freezing test