EMULSIONS An emulsion is a dispersion in which the dispersed phase is composed of small globules of a liquid distributed throughout a vehicle in which it is immiscible. Classification of emulsions :. Based on size of liquid droplets 0. Emulsifying Agents: It is a substance which stabilizes an emulsion. Rate of coalescence measure of emulsion stability. It depends on: a Physical nature of the interfacial surfactant film. In case of non-ionic emulsifying agents, charge may arise due to i adsorption of ions from the aqueous phase or ii contact charging phase with higher dielectric constant is charged positively.
Steric barrier dehydration and change in hydrocarbon chain conformation. Viscosity may be increased by adding natural or synthetic thickening agents. Inversion of Emulsions Phase inversion.
Addition of electrolytes and other additives. Emulsion Breaking.
BITUMEN EMULSION – WHAT, WHY & HOW?
This is irreversible. Protect emulsions against the extremes of cold and heat. Emulsions may be adversely affected by microbial contamination. General Guidelines:. More polar the oil phase, the more hydrophilic the emulsifier should be.
More non-polar the oil phase more lipophilic the emulsifier should be. Learn more about Scribd Membership Home. Read Free For 30 Days. Much more than documents. Discover everything Scribd has to offer, including books and audiobooks from major publishers. Start Free Trial Cancel anytime. Document Information click to expand document information Date uploaded Jun 04, Did you find this document useful?
Is this content inappropriate? Report this Document. Flag for inappropriate content. Download Now. Related titles. Carousel Previous Carousel Next. Jump to Page. Search inside document. Pharmaceutically acceptable emulsifiers must also : be stable.The study investigated the aging properties of modified bitumen penetration grade PG binder. The aging was simulated using the rolling film oven RTFOT and pressure aging vessel PAV for short-term and long-term aging during production and lying of asphalt mixtures, though the actual time of long-term aging in the field varies depending on paving times and usage.
The empirical tests, which include penetration and softening points, were conducted to ascertain the binder consistency and also the viscosity of the binder was investigated before and after aging. Results from the study indicated that aging resulted in oxidation of the bitumen with increase in the stiffness of the binder. It was observed that aging increased the viscosity, decreased the binder penetration and increased the softening point of the modified bitumen.
It could be concluded that aging increases hardness, thereby decreasing the penetration and increasing the binder softening point and viscosity. Aging in bitumen normally resulted from the weathering of the binder due to oxidation. The aging of bitumen is one of the principal factors causing the deterioration of asphalt concrete pavements. The aging modes of failures includes fatigue, thermal induce cracks, and raveling.
In practice the actual time for short-term and long-term aging in construction sites varies and depends on hauling distances and period of pavement usage John, R. David There are two basic mechanisms involved in binder aging, these include an irreversible process like chemical changes of the bitumen, consisting of oxidation of bitumen molecules, and loss of volatile components which subsequently has an impact on the rheological properties of the binders.
The reversible process is the second mechanism termed as physical hardening; this involves the reorganization of the binder molecular structure, under specific conditions. Xiaohu, L. Issacsson Bitumen aging can be attributed to some factors these include the binder characteristics and it content in the mix, nature of aggregates and particle size distribution, air void content in the mix.
Other factors include production related parameters such as temperature and time Edwards, Y. For variability test, the same standard temperature for RTFOT was conducted at different additional time lags of 70 min and min. After 20 hours, the air pressure is released slowly over a period 8 — 10 min using the bleed valve. The amphoterics are the most reactive in terms of reactivity are capable of forming interlinked structures because they have more than one reactive site Fig.
Rejuvenation needs to be contact with the aged binderability to penetrate this binder. Emulsifier choice is needed. Bitumen emulsion is a liquid product in which a substantial amount of bitumen is suspended in a finely divided condition.What is an Emulsion?? An emulsion is a thermodynamically unstable system consisting of at least two immiscible liquid phases one of which is dispersed as globules in the other liquid phase stabilized by a third substance called emulsifying agent.
An emulsion of phase B dispersed in Phase A C. Unstable emulsion slowly separates. The emulsifying agent black film places it self on the interface between phase A and phase B and stabilizes the emulsion. Factors affecting type of Emulsion Type of emulsifying agent used Phase volume ratio Viscosity of each phase. Microemulsions Microemulsions are thermodynamically stable optically transparentmixtures of a biphasic oil water system stabilized with surfactants.
Pharmaceutical applications of microemulsions Increase bioavailability of drugs poorly soluble in water. Topical drug delivery systems. Theory of emulsification Droplets can be stabilized by three methods i. By reducing interfacial tension By preventing the coalescence of droplets. By formation of rigid interfacial film b. By forming electrical double layer.
Change from A to B increases surface area of phase A, hence the Due to increased surface energy, the system is thermodynamically unstable. Theory of emulsification interfacial films Mono molecular Multimolecular Solid particle films. Emulsifying agents 2. Auxiliary emulsifiers. Antimicrobial preservatives 4. Emulsifying agents Added to an emulsion to prevent the coalescence of the globules of the dispersed phase.
Help in emulsion formation by Reduction in interfacial tension thermodynamic stabilization Formation of a rigid interfacial film mechanical barrier to coalescence Formation of an electrical double layer electrical barrier to approach of particles Classification of emulsifying agents Synthetic Surface active agents Monomolecular films Semi synthetic and natural Hydrophilic colloids Multimolecular films Finely divided solid particles Particulate film.
Synthetic surface active agents Description : Reduce interfacial tension and make the emulsion thermodynamically more stable. Form protective monomolecular film.
Rule of Bancroft : Type of emulsion is a function of relative solubility of surfactant. The phase in which it is soluble becomes the continuous phase. Hydrocolloid Emulsifying agents Description - Provide a protective sheath Multimolecular films around the droplets - Impart a charge to the dispersed droplets so that they repel each other - Swell to increase the viscosity of the system so that droplets are less likely to change.
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Classification of Hydrocolloid emulsifying agents Semi synthetic Multi molecular films Methyl cellulose Carboxy methyl cellulose. Finely divided solids Description : Finely divided solid particles that are wetted to some degree by both oil and water act as emulsifying agents. This results from their being concentrated at interface, where they produce a particulate film around the dispersed droplets to prevent coalescence.
Metallic hydroxides Magnesium hydroxide, Aluminium hydroxide. Auxiliary emulsifying agents Auxiliary Secondary emulsifying agents include those compounds that are normally incapable themselves of forming stable emulsion. Their main value lies in their ability to function as thickening agents and thereby help stabilize the emulsion. Forms a true emulsifier when reacted with alkali. Sodium Sodium salt of the carboxy carboxcymethyl methyl esters of cellulose cellulose Stearic acid A mixture of solid acids from fats, chiefly stearic and palmitic.Toggle navigation.
Help Preferences Sign up Log in. Featured Presentations. Emulsion - To cover unpleasant taste. To increase oral absorption To cover unpleasant taste.
Physical nature of the interfacial surfactant film Temp affects Interfacial tension, D, solubility of surfactant, viscosity of An oil-in-water emulsion formulation has been developed as a subcutaneous The emulsion is manufactured using a 6-bladed turbine.
Emulsion - Bottle method The bottle is capped and thoroughly shaken. Bottle method Emulsion Chemistry Typically surfactant, The water, oil and soap scenario. Fabrication of nano microstructured components Emulsion chambers - Emulsion chambers. Galen AD- rose water in molten one part beeswax, parts olive oil Dan Wegman, P. Emulsions and Microemulsions - Emulsions and Microemulsions Emulsion: A dispersion of droplets of one liquid in another, immiscible liquid Macroemulsions d nm Miniemulsions nm.
Emulsions and Microemulsions Emulsion: A dispersion of droplets of one liquid in another, immiscible liquid Macroemulsions d nm Miniemulsions nm. Emulsions and Microemulsions. Dielectric relaxation in percolation : statistical fractal description? Morphology parameters The nature of dielectric polarization in ionic microemulsionsTo browse Academia.
Skip to main content. Log In Sign Up. Deby Linsha, Y. Preethy Dharanya, V. Vinodhini and C. Almost all type of construction is built with or upon the soil. If the sub grade is not enough good the whole structure will face failure such as cracks.
Therefore the sub grade is normally replaced with stronger soil material so as to improve the strength but this is not economical.
In this project the strength of soil is increased by adding bituminous emulsion instead of replacing with stronger soil. The initial strength of the soil is determined by conducting soil tests such as sieve analysis, plastic limit, liquid limit, shrinkage limit, Modified proctor compaction test and California bearing ratio tests.
Key words: bitumen, bituminous emulsion, shear strength, soil stabilisation. Cite this Article: R. International Journal of Civil Engineering and Technology, 7 6, pp. In order for the foundation to be strong, the soil around it plays a very critical role.
So we need to have proper knowledge about their properties and factors which affect their behaviour to work with soil. The process of soil stabilisation helps to achieve the required properties in a soil needed for the type of construction work. In this thesis, the strength of the soil is improved by using bituminous emulsion. As bitumen is an oil product it cannot be mixed with water. Hence an emulsifier a surface active agent is added with water before bitumen. Addition of emulsifier with water before adding bitumen into minute particles and keeps it dispersed in suspension.
The term emulsion means that dispersion of small droplets of one liquid in another liquid. Types of emulsion are oil —in-water continuous phase is water and the disperse phase is an oily and water-in-oil continuous phase is an oil and the disperse phase is water. Here the emulsifier is used as kerosene with water.
Initially the properties of soil are determined by using conducting sieve analysis, plastic limit, liquid limit, specific gravity and shrinkage limit. The strength of soil is determined by modified proctor compaction test and California bearing ratio tests and the results are compared with the soil after treated with bituminous emulsion. Pavithra 1.
Objective Verdict the variation of strength in the soils by using the bitumen emulsion performance different proportions applied and determining the variation in properties of soil.
The methodology of this study is given in the following flow chart. Figure 1 Methodology Chart 3. The presence of water on the surface will prevent adhesion. Under some conditions water may be absorbed by minute quantities of inorganic salts in the bitumen or filler in it. The penetration is a measure of hardness. Typical results are 10 for hard coating asphalt, 15 to 40 for roofing asphalt and up to or more for water proofing bitumen.
Deterioration, or loss of the desirable properties of bitumen, takes the form of hardening. Resultantly, decrease in adhesive and flow properties and an increase in the softening point temperature and coefficient of thermal expansion. Ductility values ranges from 0 to over depending on the type of bitumen.Cationic Emulsion. Anionic Emulsion. Bitumen Emulsion Specification. Asphalt Emulsion Application. Testing Asphalt Emulsion.
Cationic Emulsified Bitumen Tack Coat. Bituplast Emulsified Bitumen Plastic Asphalt. Bitumen Emulsion in Chip Seal. Bitumen Emulsion in Seal Coat. Bitumen Emulsion in For Fog Seal.
Bitumen Emulsion in Slurry Seal. Bitumen Emulsion in Sand Seal. Bitumen Emulsion in Micro-Surfacing. Bitumen Emulsion in Cold Mix.
Bitumen Emulsion in Mulching. Bitumen Emulsion for Primer and Waterproofing. Recycling Applications with Asphalt Emulsions. Bitumen is the oldest known thermoplastic material in use today. Its usefulness and appeal derive from its simple thermoplastic property of being a thin liquid at high temperature and a virtual solid at ambient temperature. For many applications, these conditions are both essential and desirable allowing rapid throughput from hot bulk bitumen delivery through to final use without any reheating.
The reasons may be a combination of the process requirements, the application techniques, safety and environmental requirements or final product properties. Bitumen emulsion is heterogeneous, two-phase systems consisting of two immiscible liquids, bitumen and water, stabilized by a third component, the emulsifier. The bitumen is dispersed throughout the continuous aqueous phase in the form of discrete droplets, typically 0. Bitumen emulsions can be divided into three classes of which the first two, in volume terms, is by far the most important:.
If an electric charge is passed through an emulsion containing negatively charged particles of bitumen, the droplets will migrate to the anode; hence the emulsion is termed anionic. Conversely, positively charged particles will migrate to the cathode and these emulsions are known as cationic emulsions. Bitumen droplets in nonionic emulsions are neutral and consequently will not migrate to either pole. Such nonionic emulsions include clay emulsions. Initially, efforts were made to form emulsions by purely mechanical means, but it soon became apparent that whilst a dispersion could be formed by mechanical shear, the dispersion was not stable unless a third component, the emulsifier, was present.
Initially naturally occurring organic acids in naphthenic bitumen were utilized. The addition of sodium or potassium hydroxide to the aqueous phase saponified turned into soap the acids and stabilized the dispersion. Bitumen Emulsions have being developed and exponentially increased sinned they were created in They are primarily used for tack coats for use in between hot mix asphalt layers and prime coats for thin hot mix surfacing layers or a chip seal pavements.
Bitumen Emulsion is an area where technological progress is still being made to meet the requirements of pavement engineering. Anionic emulsions were first developed.Hey wait, we know that bitumen is a oil product and it cannot be mixed with water.
That is why we add an emulsifier a surface active agent with water before adding bitumen. Addition of emulsifier with water facilitates breaking of bitumen into minute particles and keeps it dispersed in suspension. Therefore we can say that a bitumen emulsion is a liquid product consisting of three things, i. In the 1 st step water is mixed with appropriate emulsifying agent and other chemicals. The type of emulsifier to be used depends upon the ionic nature of the mix.
The 2 nd step is the addition of bitumen with the water-emulsifier mix. This is done in a colloidal mill. Water-emulsifier mix and bitumen is pumped to a colloidal mill. The colloidal mill breaks the bitumen into tiny droplets. The average diameter of these tiny droplets of bitumen is about 2 micron. Here comes the role of emulsifier. Emulsifier creates a coating of surface charge around the bitumen droplets that helps to keep these tiny particles away from each other.
It also helps to keep these particles in a dispersed form. Depending upon the type of surface charge, bitumen emulsions are primarily classified into the following two types. In case of an anionic bitumen emulsionbitumen particles are electro-negatively chargedwhere as for cat-ionic emulsionsbitumen particles are electro-positively charged. Now days cationic bitumen emulsion are most commonly used. The choice of bitumen emulsion i. In case of silica rich aggregates, the surface of the aggregates are electro-negatively charged.
Therefore a cationic emulsion should be used. This will help better spreading and binding of bitumen with aggregates. When bitumen emulsions are applied on aggregates, water starts to evaporate causing separation of bitumen from water. And then bitumen spreads on the surface of the aggregate and acts as a binding material and slowly attains its strength.
Depending upon the speed at which water evaporates and bitumen particles separate from water, it is classified into following 3 types. In case of rapid setting emulsion, bitumen is intended to break rapidly. Therefore this type of emulsion sets and cures rapidly. Medium setting emulsions do not break spontaneously when applied on aggregates. But the process of breaking starts when fine dusts of minerals are mixed with aggregate-emulsion mix. Slow setting emulsions are manufactured by using special type of emulsifier, which makes the setting process very slow.
These types of emulsion are relatively stable.