In the bitumen emulsion production process, many users will encounter the same problem: the same equipment, the same raw materials, sometimes emulsified bitumen fine and uniform, sometimes there are caking, demulsification, oil slick, short storage time and other problems.At its root, more than 90% of emulsification failures and substandard product quality stem from inaccurate emulsifier ratio and irregular fusion process.
The precise proportion of emulsifier is the core of bitumen emulsion production, which directly determines the stability, adhesive force, construction applicability and storage period of emulsified bitumen.Combined with the practical operation experience of front-line production, this paper explains in detail the complete method, core points and fusion skills of accurate emulsifier proportioning, helps the construction personnel to quickly master the standardized proportioning process and eliminate the quality problems of finished products.

First, understand the core principle: why does the matching accuracy determine the success or failure of emulsification?

The essence of bitumenemulsification is to shear and disperse high temperature liquid asphalt into micron particles through the surface activity of emulsifier, and evenly disperse them in soap solution to form stable oil-water mixture system.
The core function of emulsifier is to "encapsulate asphalt particles":
1, too little ratio: bitumen particles can not be completely wrapped, particles are easy to adhere to polymerization, rapid layering, demulsification, agglomeration after production, can not be used for pavement construction;
2. Too much ratio: It not only increases construction costs, but also leads to high viscosity of emulsified asphalt, slower drying speed, slow pavement formation after construction, insufficient strength, and even oil flooding and slipping problems;
3. Accurate proportion and uniform fusion: bitumen particles are completely wrapped, emulsion is fine and uniform, storage stability is strong, bonding performance is up to standard, and it is perfectly suitable for various construction scenarios such as permeable layer, sticky layer and slurry seal layer.
Therefore, it is the premise of producing qualified emulsified bitumen to master accurate proportion and standardize fusion technology.

II. Core standard for precise emulsifier ratio (general industry parameters)

Different types of emulsifiers, different types of bitumen, different construction scenarios, the proportion parameters slightly fluctuate, the following is the engineering general accurate proportion benchmark, can be directly used as a production reference:
1. Conventional emulsifier dosage: calculated according to the proportion of bitumen mass, the dosage of conventional cationic and anionic emulsifiers is 1.8%~3.5%; the median value of ordinary road construction sticky layer and permeable layer is 2.5%, and the slurry seal layer and micro-surface can be adjusted to 3%~3.5% according to working conditions.
2. Oil-water ratio standard: the standard production ratio is 60%~65% bitumen and 35%~40% soap solution, which is suitable for most bitumen emulsification equipment and has the best stability of finished emulsion.
3, auxiliary auxiliary agent ratio: adjust the pH of hydrochloric acid, soda ash and other additives, need to follow the emulsifier dosage accurate ratio, can not be added at will, to avoid destroying the emulsion system balance.

3. Accurate emulsifier ratio + uniform fusion complete practical steps

Accurate mixing is not only "accurate weighing", but also needs to be matched with the correct dissolution, heating, feeding, fusion process, otherwise even if the matching value is correct, there will be uneven emulsification problem.The complete standardized operating flow is as follows:
Step 1: Accurate measurement to eliminate estimation errors
A lot of field construction problems stem from "empirical estimation of feeding".Construction production must abandon the estimation method and adopt electronic scales for accurate weighing throughout the process.According to the total production volume of the day, accurately weigh the dosage of emulsifier, clear water and auxiliary agent in strict accordance with the mixing ratio, record the proportion data of each batch, form a standardized production account, and avoid batch quality deviation.
Step 2: Dissolve in warm water to ensure full activation of emulsifier
Emulsifiers do not fully activate in cold, hot boiling water, which is a key detail that is easily overlooked.The optimum temperature for dissolution is 45℃~55℃ warm water.First, inject clean water into the proportioning tank, raise the temperature to the standard temperature, and slowly put the weighed emulsifier into it, so as to avoid the phenomenon of agglomeration and aggregation caused by a large amount of one-time input, and prevent incomplete dissolution from the source.
Step 3: Stir at constant speed to achieve complete fusion activation
After the emulsifier is added into warm water, the stirring system needs to be started to stir at a constant speed, and the stirring time is controlled within 5~8 minutes until the solution is free of particles, flocculent substances, and the whole is clear and uniform, forming qualified soap solution.At this time, the emulsifier molecules are fully activated, the surface activity reaches the best state, and the bitumen coating ability is perfect.
Note: The stirring speed should not be too fast to avoid a large amount of foam in the soap solution, which will affect the subsequent emulsification production.
Step 4: Accurate adjustment of acid and alkali, balance of emulsion system
After activation, the pH value of the soap solution needs to be accurately adjusted according to the type of emulsifier: the cationic emulsifier needs to be fine-tuned acidic, and the anionic emulsifier fine-tuned alkaline.pH deviation will directly offset the emulsifier effect, resulting in accurate ratio but emulsification failure, which is the key supporting step of accurate ratio, indispensable.
Step 5: Emulsification at constant temperature to stabilize the quality of finished products
After the soap solution preparation is completed and the bitumen is heated to the standard temperature, the asphalt emulsification equipment is started, the feeding speed is controlled to be uniform and stable, and the bitumen and the activated soap solution are fully sheared, fused and dispersed in the grinding chamber, and finally the emulsified asphalt finished product with fine particles and uniform and stable particles is produced.

IV. Key practical skills of precise matching to greatly improve the stability of finished products

1, according to the proportion, now ready to use: emulsion soap should not be stored for a long time, activated emulsifier standing for too long will be active attenuation, it is recommended to re-match before each batch of production, to ensure the best activity.
2, according to the temperature fine-tuning parameters: summer high temperature construction, can appropriately reduce 0.2%~0.3% emulsifier content, avoid emulsion too thin, stability deterioration; winter low temperature can be slightly increased content, ensure adequate emulsification.
3. Fixed raw materials and reduced variables: After replacing bitumen brand and emulsifier model, it is necessary to re-test the proportion, and the old parameters cannot be used to avoid poor compatibility of raw materials leading to abnormal emulsification.
4, equipment stability is the foundation: to ensure that the emulsion equipment shear pressure is stable, the stirring system is normal, the temperature control is accurate, and the precise ratio must be matched with stable equipment to produce high quality finished products.

V. Common matching errors and solutions

Problem 1: Oil slick and fast delamination on the emulsion surface: the reason is insufficient emulsifier content or incomplete dissolution; solution: precise supplement ratio, prolong stirring time, and ensure complete activation.
Problem 2: emulsion viscosity is too high, slow drying: the reason is excessive addition of emulsifier; solution: strictly according to the standard mixing ratio, reduce redundancy, control production costs.
Problem 3: fine particles and lumps appear after production: the reason is emulsifier agglomeration and uneven local fusion; solution: warm water batch feeding, uniform stirring, to prevent agglomeration.

VI. SUMMARY

The precise proportion of emulsifiers is not based on "simple weighing", but on a complete set of standardized processes of precise measurement, scientific dissolution, full activation, parameter adaptation and standardized fusion.Accurate proportioning and standardized technology can not only completely solve quality problems such as demulsification, layering and oil slick, ensure the construction effect of emulsified bitumen, but also accurately control the cost of consumables and avoid waste of raw materials.
Mastering this set of mixing and fusion methods, combined with stable bitumen emulsification equipment, batch, stable and standardized emulsified bitumen production can be realized, which can fully meet the needs of various road maintenance and pavement construction projects.