Is it normal for water reducing agent to crystallize at low temperatures? What are the main symptoms?

The water-reducing agent itself has a high water-reducing rate and excellent working performance. It is especially suitable for formulating high durability, large fluidity, high slump retention, high strength and fair-faced concrete projects. Therefore, many of its applications are accustomed to high Development requirements for functional concrete. However, in winter, the crystallization problem of sodium sulfate greatly restricts the use of water-reducing agents. The specific performance is:

In winter, water-reducing agents are also used, and early-strength agents and antifreeze can be added as needed; early-strength agents can increase the early strength of concrete, speed up the form removal time, and can also be used. The setting time of concrete is slightly advanced. If the temperature is below 0 degrees, antifreeze can be added to prevent the concrete from freezing

Water-reducing agent must be added because water-reducing agent can reduce the water consumption of concrete and the amount of cement. Save costs and improve concrete strength

1. When the outdoor temperature is too low, the water-reducing agent will separate into scattered crystals in the shape of whiskers and short needles, which will then cause chain extension, development and It grows up and causes blockage of pipes and valves. As a result, the water-reducing agent cannot enter the mixer, causing the mixing station to be unable to produce normally.

2. While sodium sulfate is crystallizing, it will inevitably absorb some of the active ingredients of the water-reducing agent, which will cause the water-reducing rate of the admixture to decrease after crystallization, causing concrete quality accidents.

Precautions for using water-reducing admixtures in winter

First of all, I think it should be a problem of dosage. Pay attention to the dosage to avoid segregation. In addition, if you mix the admixtures yourself, you must Pay attention to the amount of retarder, and also do antifreeze work. There will be small ice stubble in the mother liquor of the admixture here, so we should pay attention to this precaution

In winter, water-reducing agent is needed, and early-strength agent is also used as needed. Antifreeze can speed up the mold removal time. , the concrete setting time is slightly advanced. If the temperature is below 0 degrees, antifreeze can be added. To prevent concrete from freezing, water reducing agent must be added, because water reducing agent can effectively reduce the amount of concrete and cement used, saving costs.

The temperature difference between day and night changes greatly in winter. In production control, we should always pay attention to the changes in slump of concrete and adjust the amount of water-reducing agent in a timely manner to achieve the principle of low mixing at low temperatures and high mixing at high temperatures.

In the process of using water reducing agent, the water consumption of concrete must be strictly controlled. Once excessive water is used, concrete will segregate, bleed, harden, and have excessive air content.

During the use of water-reducing agents, the impact on the dry shrinkage properties of concrete is relatively small, but this does not mean that concrete mixed with water-reducing agents does not need to be cured. Preliminary maintenance should be strengthened to prevent cracking. phenomenon</p