Dependence of water reducing effect on water reducing agent dosage

The water-reducing effect is highly dependent on the amount of water-reducing agent

The admixture used is composed of concrete, slaked lime and fly ash powder, and the total admixture output is 477kg/m3. The results of the soil experiment show that when the content of the polycarboxylic acid-based water-reducing agent PC is increased from 0.80% to 1.40%, the “water-reducing rate” increases from 18.1% to 32.4%. It can be seen that the polycarboxylic acid-based water-reducing agent PC The water-reducing effect of water-reducing agent is highly dependent on its dosage.

In specific construction projects, the admixture can be composed of concrete and slaked lime, fly ash powder, silica fume, etc. The admixture dosage therefore exceeds 400kg/m3, and for concrete mixed with water-reducing agent Characteristics are specified in various aspects, such as water volume size, cohesion, water solubility, initial setting time, tensile strength, etc. However, when inspected in accordance with relevant specifications, only concrete is used, and the concrete dosage is 330kg/m3, or It is 390kg/m3 when inspected according to underwater concrete agent specifications. The water-reducing effect of polycarboxylic acid-based water-reducing agents is highly dependent on its dosage, and as the dosage of admixtures increases, this dependence becomes even greater. At the same time, the water-retaining solubility of the polycarboxylic acid-based water-reducing agent is also closely related to the amount of water-reducing agent.

For example, a certain type of polycarboxylic acid superplasticizer (PCA, solubility 20%), in concrete with admixture dosages of 330, 380, 440 and 550kg/m3, ” As we know, under the same admixture dosage, the relationship between the water-reducing effect of polycarboxylic acid-based water-reducing admixture and the dosage is that as the dosage of water-reducing agent increases, the relationship between Expansion, but there are often exceptions, that is, after reaching the required dosage, there may even be a situation where the water-reducing effect “decreases” as the dosage increases. This does not mean that the water-reducing effect decreases as the dosage increases, but because of this At that time, serious bleeding occurred in the concrete, the concrete mixture agglomerated, and the fluidity could not be reflected by the slump method. In order to ensure that the inspection results of our polycarboxylic acid superplasticizer products are all qualified, the specific product dosage during re-inspection cannot be too high.

Therefore, the product quality inspection report reflects only some basic data, and the application function of a certain type of product should be calculated based on the actual experimental results of the construction project.

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