What is concrete accelerator？
The alkali-free concrete accelerator is a new generation of high-performance, chlorine-free, and alkali-free environmentally friendly products developed by using new materials and new processes. It has good compatibility with various types of cement and can be used with large imported wet spray machines. Reduce dust in construction, high efficiency, and environmental protection, and can significantly improve economic benefits.
Accelerating admixtures Advantages and Features
(1) Good homogeneity: This product is a colorless or light green liquid with good homogeneity and no delamination.
(2) Low dosage: The recommended dosage is 3% to 8% of the cement mass. The cement concrete sets and hardens quickly, and the initial and final setting interval is short.
(3) Good durability of concrete: because alkali-free concrete accelerator admixture does not contain a large number of alkaline substances like alkaline accelerators, it greatly reduces the damage to concrete caused by the introduction of alkaline substances, and reduces the risk of material reaction and improve the durability of concrete.
(4) Health and environmental protection: alkali-free cement accelerator does not contain alkaline cations and is neutral or weakly acidic, which will not cause corrosive damage to the skin and health of construction workers. The alkali-free accelerator reduces the dust concentration and the amount of rebound during the spraying process, which greatly improves the construction environment.
(5) Small rebound rate: Experience shows that the rebound rate of alkali-free accelerating admixtures for spraying is less than 15%. The use of alkali-free accelerating admixtures can reduce the waste of materials and the labor and equipment costs required for cleaning the rebound waste, which is economical. The benefits are obvious.
(6) The difference in strength: the alkali-free accelerator admixtures have high early strength and small late strength loss. The use of alkali-free accelerators to improve the support strength can reduce the amount of cement and reduce the cracking and spalling. The input cost of the secondary repair of slag and roadway deformation reduces the production cost.
(7) Excellent adaptability: suitable for various cement types, within the range of 3%~8%
(8) It has no adverse effect on the durability of concrete. Since the alkali-free liquid accelerator is a non-chloride accelerator, the destructive effect on concrete caused by the introduction of alkaline substances, such as alkali-aggregate reaction, is greatly reduced; The content of chloride is limited, and corrosion of steel bars is avoided.
(9) There is no dust during the spraying process, and the amount of rebound is reduced, thereby protecting the health of the construction workers and reducing the waste of materials.
(10) Hardened concrete has good compactness and impermeability and can be formulated with high-strength shotcrete.
Applications of accelerator in concrete
Alkali-free liquid concrete curing accelerator is suitable for shotcrete construction and leak plugging, ground Cement concrete rapid construction, and concrete emergency rescue, repair, and reinforcement works.
How to use the concrete accelerator and matters needing attention
(1) Dosage: The dosage of an alkali-free liquid concrete accelerator depends on the temperature of the concrete, the environment, and the base, as well as the activity and setting time of the cement used, early strength, etc. Based on the above factors, the recommended dosage of alkali-free liquid accelerator is 3%-8% by weight of cement.
(2) Dry spraying process: The concrete is dry mixed in advance, the alkali-free liquid concrete accelerator is added to the water through the metering pump, and the water is added to the concrete mixture through the nozzle.
(3) Wet spraying process: The concrete is mixed with water in advance, and the alkali-free liquid concrete accelerator enters the compressed air pipeline through the metering pump and is sprayed from the nozzle together with the concrete.
(4) In these cases, full attention should be paid to the accuracy of the admixture dosage. The best water-cement ratio of concrete is ≤0.45. In the case of a lower water-cement ratio, better results can be obtained even if the amount of alkali-free liquid concrete accelerator is small. Water-cement ratio>0.5 will prolong the setting time and reduce the early strength of the concrete.
(5) The alkali-free liquid concrete accelerator has good adaptability to the consistency of concrete and is suitable for shotcrete with large slump (>200mm).
(6) If the dosage used is greater than the recommended dosage, it will cause too slow coagulation and early strength drop, which will seriously affect its structure and adhesion.
(7) Before using the alkali-free liquid concrete accelerator, the metering pump, including the pumping liquid (filter) and the accelerator pipeline, must be rinsed with water. During use, the entire pump system must be cleaned daily to prevent clogging.
Packaging and storage of concrete accelerator
The alkali-free cement accelerator is packed in plastic barrels in tons and can also be packaged according to user needs.
Plastic buckets should be handled with care so as not to break.
It must be stored in the original airtight container, in a cool, dry, and ventilated place, avoid moisture, and the temperature is five ℃ to 35 ℃.
Concrete accelerators cannot be stored in metal containers. Stir the product well before use to avoid precipitation.
Shelf life of concrete accelerator
The storage period of the alkali-free liquid accelerator is six months if stored in the recommended original airtight container.
