How To Test The Stability Of Polycarboxylate Superplasticizer

Post Date:10,Oct,2023

The high performance superplasticizer represented by polycarboxylate superplasticizer has the advantages of low content, high water reduction rate, good slump retention performance and low shrinkage, and the polycarboxylate superplasticizer superplasticizer has a certain amount of causing, which makes the fluidity, frost resistance and water retention of concrete better than the traditional superplasticizer. Due to the diverse synthesis process of polycarboxylate superplasticizer, the product quality of different manufacturers is very different, coupled with the production process, due to the fluctuation of the quality of concrete raw materials, the change of water content in sand, the error of the measurement system and other reasons, resulting in the unstable work of concrete mix (easy to separate or slump loss too fast) in the construction process of polycarboxylate superplasticizer. Can't even 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 achieve stable quality of concrete.

In the selection of polycarboxylate superplasticizer in addition to the basic performance tests, such as solid content, water reduction rate, slump retention and other performance tests, the sensitivity of polycarboxylate superplasticizer should be tested to comprehensively evaluate the quality of polycarboxylate superplasticizer.

(1) Detection sensitivity to change of dosage

Adjust the test concrete mix ratio to the condition that the workability and slump retention of the concrete mix meet the requirements, keep the dosage of other raw materials of concrete unchanged, increase or decrease the amount of admixture by 0.1% or 0.2% respectively, and detect the slump and expansion of concrete respectively. The smaller the difference between the measured value and the basic blending ratio, the less sensitive it is to the change of the mixing amount. It is shown that the water reducing agent has good sensitivity to the dosage. The purpose of this detection is to prevent the state of the concrete mixture from sudden change due to the error of the measurement system.