Masterbatch Powder of Liquid Alkali-free Accelerator

Masterbatch Powder of Liquid Alkali-free Accelerator

Keywords

Liquid alkali-free accelerator, masterbatch, powder, concrete accelerator, shotcrete accelerator

Product introduction
This product is a core powder raw material for preparing and producing liquid alkali-free accelerator. When producing, just add aluminum sulfate and water and stir to dissolve. The production process is simple and no heating is required. The accelerator product produced meets the national standard GB35159-2017 "Accelerator for Shotcrete".
Product features of the accelerator
1. The alkali-free accelerator made with this product is a uniform and stable accelerator with good fluidity, and its state can be maintained for at least 30 days.
2. The accelerator dosage is 6-9% of the cement mass;
3. The effect of the accelerator on the setting time: According to the national standard GB35159-2017, the initial setting of the cement paste is less than 5 minutes, and the final setting is less than 12 minutes;
4.  The influence of the accelerator on the compressive strength: According to the national standard GB35159-2017, the compressive strength of the specimen added with the accelerator is greater than 7M in one day, and the compressive strength of the specimen added with the accelerator reaches at least 90% of the strength of the benchmark specimen relative to the 28-day compressive strength of the benchmark specimen.
5. Good adaptability to cement, within the range of 6-9% of cement mass, it meets the performance indicators and requirements of GB35159-2017 "Accelerator for Shotcrete";
6. No adverse effect on the durability of concrete, such as alkali-aggregate reaction;
7. Liquid accelerator has rapidly promoted the wet spraying of concrete. Wet spraying is not only environmentally friendly but also more beneficial to the health of construction workers, and it also reduces the waste of raw materials;
8. The accelerator is pumped and mixed with concrete at the nozzle. The liquid accelerator produced with this product is a fluid slurry mixture. Do not install a filter on the hose of the accelerator pump to prevent the accelerator from being sucked normally from the barrel;
9.  Please be sure to clean the accelerator pump before spraying concrete to prevent it from mixing with other accelerator residues and reacting chemically to block the accelerator pump.

Technical indicators
Appearance: White or off-white powder
Bulk density (23℃) (kg/m3): 580±50
pH value (23℃) (10% aqueous solution): 3.0-3.5
Alkali content%: ＜1

Production process of preparing accelerator with this product as the core raw material
Aluminum sulfate and water can be added in proportion and stirred to dissolve:
This product / Aluminum sulfate (including crystal water) /  Water
20~30%  /   30~40%  /  40%
The above ratios can be adjusted within a range of 10% according to the adaptability of the cement used.

Operation steps: (Take the preparation of 10 tons of liquid accelerator finished product as an example)
1. Weigh 4 tons of clean water into the mixing bucket and turn on the mixing equipment.
2. Weigh 2 tons of this product powder and pour it into the mixing bucket bag by bag at a uniform speed.  When the powder is poured into the bucket, it should be done slowly and evenly to avoid clumping and prolonging the mixing time.
3. After it is completely dispersed, weigh 4 tons of aluminum sulfate and add it to the mixing bucket bag by bag at a uniform speed.
4. Continue stirring for 3 hours after the filling is completed. After the aluminum sulfate is completely dissolved, turn off the mixing equipment.
5. Be sure to put a filter screen at the discharge port to filter out impurities in the finished product. Open the discharge valve and put the liquid alkali-free quick-setting agent into a ton barrel for standby use.

Precautions for producing alkali-free quick-setting agent
1. The water used should be clean water without impurities, and tap water is best. And the water temperature should not be lower than 10℃. The higher the water temperature, the faster the dissolution, but it should not exceed 40℃;
2. The speed of the mixing bucket is 70-100 rpm, and the motor power should be greater than 7.5kw. Too small motor power will affect the mixing and dissolution speed of the dry powder;
3.  The stirring time should be greater than 3 hours to ensure that the product and aluminum sulfate have enough time to fully dissolve. When the powder particle size is large, the stirring time should be extended accordingly to ensure complete dissolution;
4. Be sure to place a filter screen at the discharge port, and the screen fineness should be 80 mesh or 120 mesh or finer. It is recommended to install a set of filter screens at the discharge port of the mixing barrel and the ton barrel to ensure that no insoluble impurities enter the liquid accelerator product;
5. The ambient temperature also affects the dissolution rate of this product and aluminum sulfate. Therefore, the production of liquid accelerator should be carried out in a factory with insulation measures at a temperature not lower than 10°C. If the ambient temperature is low, the dissolution rate of this product and aluminum sulfate will be reduced, and the dissolution stirring time needs to be extended.

Storage conditions
1. Storage: The inner and outer packaging bags should be kept intact to prevent water absorption and moisture.
2. Storage of the accelerator: After the accelerator is prepared, the storage temperature should be greater than 5°C. The liquid product should be stored in a plastic/glass fiber reinforced plastic barrel.
3. The quick-setting agent product is acidic and will react chemically with metal materials. It is strictly forbidden to use iron barrels for storage.

Storage time
1. This product can be stored in a sealed state for 2 years, and can be stored for 3 months after being prepared into liquid.
2. If the liquid product is stored for a long time, it is recommended to stir it simply when using it to eliminate the visual micro-stratification phenomenon.

Packaging
Packaged in 25KG plastic woven bags or ton bags.

Precautions
1. This product is a soluble powder, non-toxic, non-corrosive, non-radioactive, but not edible.
2. No pollution was found to the environment during use, but it should comply with the requirements of local environmental protection regulations when it is discarded or discharged.
3. When it comes into contact with the human body and eyes, it should be rinsed with clean water as soon as possible. If it causes allergies to some human bodies, medical treatment should be sought in time.
4. The packaging of this product cannot be discarded casually and should comply with the requirements of local environmental protection regulations.