Cationic Emulsion K1-70
Bitumen Emulsion K1-70 is a cationic rapid setting bitumen emulsion that contains 67% bitumen. It is a medium viscosity emulsion used mainly for tack coating in normal overlay and patching work. Bitumen emulsion K1-700 is chocolate brown in color and is a free-flowing liquid at ambient temperature and is commonly used for Tack-Coating as well. FARAGAM company Asphalt Emulsion K1-70 cationic bitumen emulsion is made according to BS EN 13808:2013 standard and Malaysian Standard, MS 1.61 (1994).
Bitumen Emulsion is made up of three basic ingredients which include Bitumen, an emulsifying agent, and water. It is a well-known fact that asphalt and water will not mix, except under carefully controlled conditions using highly specialized equipment and chemical additives. Cationic Emulsions that have positively charged ions may be used at ambient temperatures with aggregates, which do not have to be completely dry. Emulsions are less hazardous to use and can be applied in a wider range of conditions and used for many applications including road surfacing. Asphalt emulsions are classified according to the electric charge that surrounds the emulsion’s asphalt particles (i.e. whether it is a cationic or an anionic emulsion) and how quickly the suspended asphalt particles separate from the surrounding water
Application of Bitumen Emulsion K1-70
Bitumen Emulsion K1-70 containing 67% Bitumen, is commonly used for Tack-Coating. This is applied to an underlying surface to aid with the adhesion of the following asphalt layer. Bitumen Emulsion K1-70 Is also used for Fog Sealing, Mist Spraying, Concrete Curing, Grouting, Sealing, Patching, Formation, and Sub-base and Surface Dressing. Bitumen Emulsion K1-70 is a rapid setting.
Bitumen Emulsion K1-70 is primarily used as a tack coat, to provide a bond between the existing surface and overlays e.g hot rolled asphalt, macadam, and slurry seals, or between courses in road construction.
Also, one of the main application of emulsion K1-70 is in road surface treatments and seals as:
Single surface treatment
Multiple surface treatment
Sand seal
BS 434-1:1984
Bitumen emulsions are specified in BS 434-1:1984 in a three-component alphanumeric scheme. The first part, which is the letter A or K, refers to the anionic or cationic nature of the emulsion. The second part is a number from 1 to 4 that indicates the breaking speed or stability of emulsion bitumen. A larger number indicates greater stability and, as a result, a lower failure rate. The third part of the code indicated the amount of bitumen in the emulsion in terms of percentage. for example:
K1-70 is a cationic emulsion with high breaking speed and bitumen content of 70%.
particle charge
The remainder of the sieve (coarse sieve, 710 micrometers)
Sieve residue (fine sieve, 150 micrometers)
Viscosity as flow time from a flow cup (degrees Engler or Redwood II seconds)
The amount of bitumen is basically measured by the amount of water and then the percentage of bitumen is calculated by subtracting the amount from one hundred. Therefore, the percentage obtained for the amount of bitumen includes emulsifier and solvent.
Coagulation at low temperature
Stability during storage (short-term test)
Stability during storage (long-term test)
Stability of mixed with coarse grains
Stability of cement mixture
However, only particle load, binder amount and viscosity are determined by K1-70, K1-70 emulsion is widely used for surface coating. Viscosity limits do not necessarily give satisfactory performance for emulsification in a sprayer, for example transfer distribution is required according to BS 1707:1989.
As with other aspects of highway specifications, the performance properties of the surface coating need to be determined in addition to the old parameters, and this does not mean that laboratory tests are not needed, but rather that these tests are needed for quality control.
Emulsion properties:
The amount of bitumen that is needed to reach a certain viscosity is one of the properties of the emulsion, which changes significantly if bitumen modified with polymer is used. K1-70 emulsion, based on pen grade bitumen, is generally produced with 67-70% bitumen and can perform satisfactorily in most spraying equipment. It is difficult to achieve higher bitumen content without increasing the viscosity of the emulsion beyond the point where it has adequate spreading for conventional spray sticks. However, by using modified polymer bitumen, emulsions can be produced that contain 80% bitumen and work as well as K1-70 emulsion in spray equipment.
This effect is evident even in small amounts of modifier up to 1% polymer in bitumen for some polymers. This is an advantage in itself (apart from the benefits of improving performance by using polymer bitumen) because it reduces the amount of water that must be transported with bitumen to evaporate after application on the road surface by 30%. The reason for this is the change in the particle size distribution of the emulsion prepared with modified bitumen compared to the normal emulsion; The former has a much wider particle size distribution than the latter.
Other properties of emulsion prepared with modified bitumen are the same as normal bitumen emulsions.
Methods of use:
In general, modified bitumen emulsions are used in exactly the same way as conventional bitumen emulsions. It should not be assumed that the use of modified polymer products provides a margin of safety for poor work practices. In contrast, modified products usually require more precision during use and have less tolerance in unstable sites and weather conditions, and their advantage lies in the level of performance that can be achieved under high traffic pressure conditions, provided that the work done with quality.
Breaking of bitumen emulsions
Basically, there are six parameters that can change the breaking properties of the emulsion:
amount of bitumen
Composition of the aqueous phase
Particle size distribution
Environmental conditions
Chippings
Use of fragile agents
Amount of bitumen:
In large amounts of bitumen, the possibility of bitumen particles colliding and accumulating with each other is higher, and as a result, the rate of emulsion breaking is higher.
Composition of the aqueous phase:
It has been shown that by reducing the amount of acid, increasing the amount of emulsifier or reducing the ratio between acid and emulsifier in the emulsion, the speed of breaking increases.
Particle size distribution:
The smaller the size of the bitumen particles, the better their distribution is, and as a result, the rate of emulsion failure decreases.
Environmental conditions:
The rate of water evaporation is affected by wind speed, humidity and temperature respectively. Temperature and humidity are related: when the air temperature decreases, the relative humidity increases. It will be difficult to work with the emulsion at night and at low temperatures, and 100% humidity will completely stop water loss.
At higher temperatures, the bitumen particles in the emulsion are more mobile and the bitumen is softer. In such conditions, the particles have a great tendency to aggregate and therefore easily clot.
Chipping:
K1-70 emulsion spray conditions start the emulsion breaking process. Therefore, chipping is necessary immediately after applying the emulsion on the road surface. It is necessary to ensure that the emulsion still has the ability to wet the chippings. When chipping is used, the rate of failure increases with the absorption of the emulsifier of the grains and the evaporation of water. Emulsifier absorption can be completely stopped by using coated chipping. On the other hand, dust can break the emulsion and prevent it from sticking to the chipping. The chipping surface area (size and shape) has a significant effect on emulsion failure.
Inside the emulsion, there are emulsifier molecules both inside the water and on the surface of the particles. Some emulsifier ions from micelles are in equilibrium with each other in a stable emulsion as shown in Figure 5.6. If some of the emulsifier ions are removed from the solution, the equilibrium is re-established by the ions of the micelles and the droplet surface. This happens when the emulsion comes into contact with mineral particles. The surface of negatively charged mineral particles quickly absorbs some dissolved ions and the charge on the droplets is weakened. This initiates the failure process shown in Figure 6.6. Rapid coagulation occurs at the point where the charge on the droplet surface is rapidly discharged. Now the mineral particles are covered by hydrocarbon chains and thus the free bitumen is strongly attached to the surface.
Use of fragile agents:
The use of brittle agents can speed up the emulsion breaking process. For emulsions that cover the surface, it is possible to spray the brittle agent at the same time or after applying the emulsion to the surface. Care is needed when using emulsion breaking agents because using too little breaking agent can be ineffective, too much can affect adhesion, and poor spreading of breaking agent can have a similar effect.
