Breaking of emulsionsThere are basically six parameters that can change the emulsion breaking properties: The amount of bitumen Blue phase composition Particle size distribution Environmental conditions Chippings Use of fragile agents Amount of bitumen: In large amounts of bitumen, bitumen particles are more likely to collide and accumulate with each other, and as a result, the emulsion failure rate is higher. Blue phase composition: It has been shown that by decreasing the amount of acid, increasing the amount of emulsion fire or decreasing the ratio between acid and emulsion fire in the emulsion, the failure rate increases. Particle size distribution: The smaller the bitumen particle size, the better their dispersion and consequently the lower the emulsion failure rate. Environmental conditions: The rate of water evaporation is affected by wind speed, humidity and temperature, respectively. Temperature and humidity are interdependent: 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 it will completely stop the 100% moisture loss of water. At higher temperatures the bitumen particles in the emulsion are more mobile and the bitumen is softer. Under such conditions, the particles have a strong tendency to accumulate and therefore easily clot. Chipping Chipping: Emulsion spray conditions K1-70 start the emulsion failure process. Therefore, chipping is necessary immediately after applying the emulsion on the road surface. It is necessary to ensure that the emulsion is still capable of wetting the chips. When chipping is used, the failure rate is increased by adsorption of emulsifiers on the particles and evaporation of water. Absorption of emulsion fire can be completely stopped by using coated chipping. In contrast, dust can break the emulsion and prevent it from sticking to the chipping. Chipping surface area (size and shape) has a significant effect on emulsion failure.Inside the emulsion, emulsion fire molecules are present both in water and on the surface of particles. Some emulsion ions of micelles are in equilibrium in a stable emulsion, as shown in Figure 5.6. If some emulsion ions are removed from the solution, equilibrium is restored by the micelle ions and the droplet surface. This occurs when the emulsion comes in contact with mineral particles. The negatively charged mineral particle surface rapidly absorbs some soluble ions and the charge on the droplets is attenuated. This starts the failure process shown in Figure 6.6. At the point where the charge on the surface of the droplets is quickly discharged, rapid clotting occurs. The mineral particles are now covered by hydrocarbon chains, so the free bitumen is firmly attached to the surface. Use of fragile agents: The use of brittle agents can speed up the emulsion failure process. For surface coating emulsions, brittle agent spraying can be used simultaneously or after application of the emulsion to the surface. Caution is required when using emulsion brittle agents because using a small amount of brittle agent can be ineffective and using a large amount can affect adhesion and poor dispersion of brittle agent can have a similar effect.
