bituminous-binders-230226122939-a993a873.pptx

bituminous-binders-230226122939-a993a873.pptxbituminous-binders-230226122939-a993a873.pptxbituminous-binders-230226122939-a993a873.pptxbituminous-binders-230226122939-a993a873.pptx

1. Bituminous and resin binders 4

2. Asphalt cement is a semi solid hydrocarbon retained after fuel and lubricating oils are removed from petroleum. It is used as binder for almost all high types of bituminous pavement. The softest grade used for pavement is 200-300 penetration . The 60- 70 penetrations is the hardest type.

3. CUTBACK OR LIQUID ASPHALT Liquid asphalt is a petroleum product consisting of asphalt cement with a liquid distillate (diesel, kerosene or gasoline). The less viscous asphalt contains diluents as little as l5%. The use of cutback is being frowned for two reasons: A. IT IS A USABLE FUEL B. IT IS AN AIR POLLUTANT

4. 01 02 03 Slow curing (SC) road soil Medium curing (MC) cutback asphalt Rapid Curing (RC) cutback asphalt CUTBACK OR LIQUID ASPHALT IS CLASSIFIED INTO:

5. 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.

6. 1. Emulsified asphalt is excellent with wet aggregate because the water medium carries the asphalt into a superior contact with the particle surfaces. 2. Emulsified asphalt is an alternate to cutback asphalt for energy and environmental objectives. It is an effective material in coating electropositive aggregate such as limestone but tend to strip from aggregates with high con- tent of silica for having strong electronegative surface charges. 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. CHARACTERISTICS

7. 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 oven tars and water gas tar.

8. The AASHTO classification of coal tars includes RT-l to RT-12 and RCTB-s to RTCB-6. RT-l is suitable for application as Tack of Prime Coat at normal temperature. The DPWH Specifications Classify Bituminous Tack Under Item 302 which provides that: 1. Bituminous materials shall be either Rapid Curing Cut Back or Emulsified asphalt. 2. Tack Coat shall be applied only to dry surfaces or slightly moist. No Tack Coat shall be applied when the weather is either foggy or rainy.

9. 3. Immediately prior to the application of Tack Coat, the road surface is lightly 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.

10. BITUMEN- RUBBER MIXTURE The bitumen rubber mixture for road pavement was experimented in Holland in the year 7929. It was adopted in the United States in 1947 and later, in European countries. The assessments of the road states that:

11. BITUMEN- RUBBER MIXTURE 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: 01 According to the report, powdered rubber foams added to bitumen has improved the stability of some but not all. 02 "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".

12. EPOXY RESIN AS BINDERS Epoxy binders are produced 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.

13. 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 2. Test for durability AASHTO T- 52 3. Test for solubility AASHTO T- 44 4. Distillation test AASHTO T- 78

14. TEST FOR BITUMINOUS BINDERS 5. Thin film oven test AASHTO T- 179 6. Flashpoint AASHTO T-48%79 7. Test for homogeneity of petroleum asphalt AASHTO 102 8. Special test for Emulsion asphalt AASHTO T- 59 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

15. PROBLEMS ASSOCIATED WITH BITUMINOUS BINDERS 5-7

16. 1. The thickness of asphalt film in the pavement, ranges from .005 to .010 mm. Test result showed that the thicker the asphalt film, the lesser is the process of aging. Where pavement has lower percentage of voids, aging is also relatively low. 2. Mixtures that are too dry, cracks and breaks easily. 3. Higher asphalt content and lower percentage of voids may cause instability of the pavement. 4. Improper construction procedures can age asphalt prematurely. One example is mixing asphalt with an overheated aggregate.

17. 5. Storing the mixed materials, or an extended period of mixing, the temperature produces substantial reduction of asphalt penetration. 6. Climatic conditions can seriously affect the behavior of asphalt binders. 7. Different brand or source has variability in behavior. The viscosity of some asphalt varies with temperature from that of the others. 8. An asphalt meeting a specified penetration requirement at 77°F but with high viscosity temperature ratio will become hard and brittle at lower temperature.

18. BITUMINOUS PAVEMENTS 5-8

19. THE BITUMINOUS PAVEMENT IS A COMBINATION OF MINERAL AGGREGATE AND BINDERS. THE MIXTURE OF ROCK MATERIAL PARTICLES WITH ASPHALT HAS CREATED SO MANY NAMES TO WIT: 1. Asphalt 6. Asphalt macadam sheet 2. Asphaltic concrete 7. Road mix 3. Mastic 8. Armor coat 4. National paving 9. Oil mat etc. 5. Plant mix

20. 1. The surface must be free from cracks or raveling due to shrinkage and fatigue failure. 2. It must withstand weather condition, including the effect of surface water, heat, cold and oxidation. QUALITIES OF ASPHALT ROAD 3. The Cationic Emulsion is very effective on high siliceous aggregates but may strip from high alkaline that carry strong positive surface changes. 4. It must posses a tight or porous impermeable surface as the case may be suitable to underlying base on sub-base. 5. It must be smooth riding and skid free surface.

21. A SATISFACTORY ASPHALT PAVEMENT COULD BE ATTAINED UNDER THE FOLLOWING CONSTRUCTION PROCEDURES : 1. Viscous asphalt binder is heated to a fluid condition and mixed with heated aggregates. The mixture is then laid and compacted while still hot. 2. Mixing liquid or emulsion asphalt with aggregates at normal temperature is either by plant or road mixing. The mixture is laid and compacted at normal temperature before the solvent evaporates or the emulsion breaks. 3. Spread and compact the clean crushed stones, sprayed with heated or emulsified asphalt binder over it. Cover the sprayed pavement with fine aggregate. This process is referred to as the "penetration method."

22. ASPHALT CONCRETE PAVEMENT 5-9

23. The term Asphalt Concrete refers to a dense graded road surface made of hot mineral aggregates, mixed with hot asphalt and laid at high temperature of about 275°F to 300°F. Asphalt concrete is the highest type of dense bituminous pavement suit- able for the most heavily traveled roads. A prime coat is first applied over untreated and treated base before asphalt concrete is laid. The purpose is to bind any loose particles of the base and likewise act as bond between the base and the pavement to deter rising moisture from penetrating the pavement. The thickness of compacted asphalt concrete ranges from 2 inches for lightly traveled road to 6 inches or more for roads where traffic is considerably heavy.

24. BITUMINOUS PAVEMENT FAILURE 5-10

25. Bituminous pavement failures are caused by excessive load. Heavy load creates deflection on the road surface, with insufficient underlying strength. Repetitious application of excessive load will roughen and crack the road pavement that ultimately result to complete failure of the roadway. Deflection on the road surface may be the effect of elastic deformation from the consolidation of the base and subsoil or from the combination of elastic and plastic deformation. Repeated heavy wheel load on highly resilient soil causes deflection leading to fatigue failure of the asphalt surface. Alligator or map cracking of the surface will be substantially evident. Elastic deformations in the sub- grade penetrate to a depth of 6.00 meters although mostly to a depth from the surface.

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