1, reducing the water effect on the concrete raw materials and the dependence of the mix ratio
Concrete water reduction rate is a very strict definition, but it is often caused by misunderstanding, in many different occasions, people always borrow the water reduction rate to express the product water reduction effect. At a lower dosage, taking polycarboxylic acid water reducing agent as an example, it has been proved that the water reducing rate is much larger than other kinds of water reducing agent, and has a good water reducing effect. However, it must be noted that compared with other water reducing agents, the water reducing effect of polycarboxylic acid water reducing agent is more affected by the test conditions.
Among the influencing factors of plasticizing effect of polycarboxylic acid water reducing agent, sand ratio of aggregate in concrete and particle gradation also have great influence. The plasticizing effect of polycarboxylic acid superplasticizer is greatly affected by the mud content of fine aggregate compared with other high efficiency superplasticizers such as naphthalene series.
2. The effect of water reduction depends greatly on the dosage of water reducer
Under normal circumstances, with the increase of water reducing agent dosage, concrete water reducing rate also increases, especially polycarboxylic acid system water reducing agent, dosage size directly affects the effect of water reducing. However, there is an exception in the practical application, that is, after a certain amount of mixing, the water reduction effect with the increase of mixing amount instead "decreased", this is because at this time the concrete mix material is cemented, concrete appears serious bleeding phenomenon, slump method can no longer express its liquidity.
