PCE special for Prefabricated Components

The effect of prefabricated components and prefabricated Polycarboxylate Superplasticizer ST605 on the performance of concrete is studied from this text. The results show that concrete mixed with ST605 has the shortest setting time and the highest surface brightness. The early strength of concrete 24h can be increased by 40% compared with that of SNF superplasticizer concrete. The appropriate amount of superplasticizer is beneficial to the early strength growth of concrete, which can better meet the construction requirements. ST605 can effectively reduce the bleeding rate of concrete and improve the durability of concrete compared with ordinary PCE. Compared with SNF superplasticizer, it can improve the quality of prefabricated components, reduce the production cost and increase the economic benefit.

Raw materials and testing methods:

1.1 Raw Materials

(1) Cement

P.O42.5R ordinary Portland cement; The fly ash is Grade I ash.

(2) The fineness modulus of machine-made sand is 2.7, the content of stone powder is 12%, and the methylene blue is 2.1; The plastic gravel of small stone 5~10mm and large stone 10~20mm is used in combination, the needle flake is less than 5%, and the crushing value is less than 15%.

(3) Tap water is used for mixing water.

(4) Water Reducing Agent –SANTOCHEM ST605.

Testing method:

Refer to the test methods specified in the relevant standards for the performance and durability of concrete mixes.

Results and discussion:

It is found that the concrete with other water reducing agents has longer setting time, the initial setting time is 6h, the final setting time is 8.5h. The setting time of concrete mixed with st605 is shortened, the initial setting time is 4h, and the final setting time is 5.5h. It is beneficial to speed up the mold removal, improve the mold turnover rate, and greatly increase the surface brightness.

The reason for this effect is that, in terms of mechanism, compared with other water reducing agents, ST605 main chain can completely cover the surface of cement particles, so the covered part is hydrated, and with the increase of alkalinity, electrostatic repulsion and steric hindrance are destroyed to accelerate the hydration reaction, thereby shortening the setting time of concrete, and a large number of polymers are introduced to improve the surface brightness. 

Effect of ST605 water-reducing agent on the early strength of prefabricated components:

The early strength of the prefabricated component is related to the turnover efficiency and lifting quality of the formwork, so the influence of the type of water reducing agent on the early strength of the prefabricated component is studied. The strength growth rate of the prefabricated component with ST605 superplasticizer was faster than that of ordinary polycarboxylic acid superplasticizer and naphthalene series superplasticizer within 24h. The 8h strength of the concrete with ST605 superplasticizer reaches 3MPa, while the naphthalene superplasticizer concrete has no strength when approaching the final setting. When the concrete meets the strength of removal and lifting (the design strength of concrete is 50% and above), the concrete with ST605 water reducing agent only needs 19h, while the naphthalene water reducing agent concrete needs more than 24h, and the strength of ordinary polycarboxylic acid water reducing agent concrete just reaches 50%. Considering the slight fluctuations of raw materials, the production strength should leave a surplus value. The concrete mixed with ST605 water reducing agent grows faster than naphthalene type water reducing agent, and the strength reaches more than 15MPa at 19h, which is about 6h earlier than naphthalene type water reducing agent concrete, speeding up the turnover efficiency of formwork and shortening the production cycle.

Testing Conclusion

Concrete with ST605 Polycarboxylate Superplasticizer in production has good maintenance performance, good working performance and easy construction; Shorten the production cycle, increase the number of production, can reduce the production cost; High early strength can optimize raw material costs and increase economic benefits.

Meanwhile, Santochem has different types of Concrete Admixtures to meet different requirements of customers, for example some customers are from extreme cold region like Russia, in this case we provide customers with anti-freezing agent, including Nitrite; while some customers need early strength agent, we have Calcium Formate here.