Properties of Polycarboxylic Superplasticizer

The common description of the performance of Polycarboxylic Superplasticizer is: high water reduction rate, very good adaptability to cement, good workability of concrete, no loss of slump in one hour, etc. In fact, the composition of cementitious materials is complex and changeable. From the perspective of adsorption dispersion mechanism, any admixture can not adapt to all situations. The good adaptability of Polycarboxylic Superplasticizerto cement is also compared with naphthalene water reducer. The workability of concrete can be divided into fluidity index and stability index. The concrete mixed with polycarboxylate superplasticizer has better workability, no obvious segregation and bleeding will occur at higher dosage or higher water consumption, and the settlement of concrete in the formwork is also small, that is to say, from the stability index, the adaptability between polycarboxylate superplasticizer and cement is obviously better than naphthalene superplasticizer. But in terms of liquidity indicators, this is not necessarily the case.

1.The adaptability of Polycarboxylic Superplasticizer is directly related to its content

2.The cement with poor adaptability to naphthalene water reducing agent generally has poor adaptability to Polycarboxylic Superplasticizer

3.The "adaptability" of specific polycarboxylic acid products is not as good as naphthalene products.

Generally speaking, the higher the water reducing rate of water reducing agent is, the more sensitive the mixing logistics mobility is to the content in its effective content range. Therefore, many engineering technicians intuitively think that Polycarboxylic Superplasticizer is too sensitive in application, and emphasize the difficulty of measurement, concrete production and control. The premise of this understanding is to convert the water reducing agent into pure solid and see the improvement of concrete flow performance with the increase of pure solid content. For example, for ordinary grade pumped concrete, the content of naphthalene water reducer can achieve the best working performance of concrete in the range of 0.65% ~ 0.85%, while the content range of polycarboxylate water reducer is 0.14% ~ 0.18%. The dosage range of naphthalene based water reducer is about 0.2%, and the dosage range of Polycarboxylic Superplasticizer is about 0.04%. In this sense, carboxylic acid water reducer is indeed more sensitive than naphthalene based water reducer.