Study on Synergistic Improvement of Properties of Low Temperature Calcium Sulphosilicate - Calcium Sulphoaluminate Cement by Water Reducer and Retarder

Abstract

Calcium sulfosilicate-calcium sulfoaluminate (TCSA) setting time is shorter while the flow rate and mechanical strength are lower. Herein, the method of synergistic regulation of polycarboxylate superplasticizer (PCE) with the compounding of β-cyclodextrin (β-CD) was adopted to solve this. The results showed that, compared to the reference sample, when the mass admixture of PCE and β-CD was 0.25% compounded with 0.05%, respectively, the setting time of TCSA was prolonged, the fluidity was increased by 118% (201 mm). And the net slurry flexural strength reached 9.5 MPa and 11.2 MPa for 7 days and 28 days, respectively, and the compressive strength reached 73.9 MPa and 103.8 MPa, which were increased by 16% and 43%, respectively. In addition, the synergistic of PCE compounded with β-CD also significantly reduced the early hydration heat rate and the total cumulative heat release, and delayed the formation of ettringite (AFt). The synergistic effect of the two admixtures, on the one hand, inhibited the early hydration of calcium sulfoaluminate, on the other hand, improved the denseness of the product due to the reduction of water consumption, thus achieving the effect of normal setting time, suitable flow and high mechanical strength.

Keywords: Ternesite-Calcium Sulfoaluminate Cement, Admixtures, Strength, Antifreeze performance, Improvement