What should I do if there is a problem with the concrete mixed with water reducer, don't worry, I have a solution
First of all, we need to know what the water reducer does? Most of the superplasticizers belong to anionic surfactants, and the commonly used ones are polycarboxylic acid superplasticizers, naphthalene superplasticizers, etc., which can greatly reduce the mixing water consumption, improve the strength of concrete, reduce the occurrence of cracks, and play an important role in the adjustment of concrete properties under the condition of maintaining the slump of concrete. Due to the decline in the quality of raw materials, the lack of professionalism of the staff and other factors, there will be a variety of phenomena in the concrete mixture mixed with water reducing agent, you can choose Zhengzhou Kexin Construction MachineryConcrete mixerAvoid such as the following:
1. Sticky stirring tank:
The cement mortar part sticks to the wall of the mixer barrel, resulting in uneven concrete, less ash and sticky concrete.
Reason: The concrete is sticky, which mostly occurs after being mixed with a retarding superplasticizer, and the cement falls into the mixing shaft, resulting in uneven powder on the edge of the tank.
Solution: 1) Pay attention to flushing and removing the remaining concrete powder in time;
2) Stir with material and part of the water first, and then add cement, residual water and superplasticizer to mix.
3) Use a large shaft-diameter ratio or compulsory mixer.
2. False coagulation.
After leaving the machine, the concrete mixing material quickly loses its fluidity and cannot even be poured for construction.
Reasons: 1) The insufficient content of calcium sulfate and gypsum in cement leads to the rapid hydration of calcium aluminate;
2) The superplasticizer has poor adaptability to this type of cement.
3) Triethanolamine content is more than 005-0.1% is very early at this time, but not final.
Solution: 1) Replace the cement model;
2) Appropriately adjust the ratio of admixtures and carry out reasonable compounding;
3) Supplementation of Na2SO4 components in admixtures.
3. Non-condensation.
After mixing with water reducing agent, the concrete has not solidified for a long time, even a day and night; Or the surface is pulpy and yellowish-brown.
Reasons: 1) The amount of superplasticizer is too large;
2) Excessive use of retarder.
Solution: 1) No more than 2-3 times of the recommended dosage, although the strength is slightly reduced, the 28d intensity is reduced less, and the long-term strength is reduced less;
2) After the final setting, the curing temperature should be appropriately increased, and the watering and curing should be strengthened;
3) Remove the formed part and re-pour.
4. Low strength
The intensity is much lower than that of the same age trial results; Or the concrete has solidified, but its strength is extremely low.
Reasons: 1) The amount of air entrainment superplasticizer is too large, so that the gas content of the concrete is too large;
2) The vibration is not enough after mixing with the gas entrainment superplasticizer;
3) The water-cement ratio is not reduced or increased.
4) The quality of the superplasticizer is not up to standard, such as the content of the active ingredient is too low.
Solution: 1) adopt other reinforcement measures or re-pouring;
2) Strengthen the vibration after pouring;
3) take measures against the aforementioned reasons;
4) Identification of this batch of superplasticizers.