Effects of superplasticizers and retarders on the fluidity and strength of sulphoaluminate cement

- The workability of SAC admixed with different types of superplasticizer and retarder was studied.
- The effects of different combinations of superplasticizer and retarder on the fluidity were quite different.
- CA and SG had little negative effects on the fluidity of paste admixed with PC.

The effects of three superplasticizers, β-naphthalenelfonic acid-based superplasticizer (BNS), aminosulfonic acid-based superplasticizer (AS) and polycarboxylate acid-based superplasticizer (PC), and two retarders, citric acid (CA) and sodium gluconate (SG), on the fluidity, flow loss and compressive strength of sulphoaluminate cement were studied. The competition adsorption effects between the retarder CA and the superplasticizers of BNS and AS were intensively and lead to low initial fluidity. Besides, there is not any competition effect between SG and superplasticizer of BNS and AS, and the combinations of the two retarders and superplasticizer of PC had better influence on the fluidity and flow loss. Furthermore, superfluous retarders would lead to decrease of compressive strength due to the inactivity of cement particle.