In addition, polycarboxylic acids are reduced due to fluctuations in the quality of concrete raw materials, changes in the water content in sand and gravel, and errors in the measurement system.During the use of the water agent, the machinability of the concrete mixture is not stable (easy to separate or slump loss too fast), even cannot meet the construction requirements.How to choose polycarboxylate superplasticizer which is easy to control and easy to produce stable quality is one of the important factors to obtain stable concrete quality.
In the selection of polycarboxylate superplasticizer, in addition to the basic performance tests (such as solid content, water reduction, water retention and other performance tests), the polycarboxylate superplasticizer should also be sensitive.Quality of polycarboxylate superplasticizer.Sensitivity to dose variations adjusts the mixing ratio of the tested concrete until the machinability and retention of the concrete meet the requirements.
The raw materials in concrete remain unchanged, respectively increase or decrease the dosage by 0.1% or 0.2%, and test the concrete slump and expansion rate.The smaller the difference between the measured value and the basic mixing ratio, the smaller the change of mixing quantity.Sensitivity, indicating that the superplasticizer is more sensitive to dose.The purpose of this test is to prevent the mixture from mutating in the concrete mixture state due to metering system errors.
