Effect of Water Reducing Agent and Retarder on Properties of Ternesite-Calcium Sulfoaluminate Cement Synthesized at Low Temperatures

Abstract

The setting time of ternesite-calcium sulfoaluminate (TCSA) is shorter while the fluidity and mechanical strength are lower. Herein, the method of synergistic regulation of polycarboxylate superplasticizer and β-cyclodextrin was adopted to solve this. The results showed that, compared to the reference sample, when 0.25% polycarboxylate superplasticizer compounded with 0.05% β-cyclodextrin, the setting time of TCSA was prolonged, the fluidity was increased by 118% (201 mm). And the net pastes compressive strength reached 73.9 MPa and 103.8 MPa for 7 days and 28 days, respectively. In addition, under the synergistic effect of polycarboxylate superplasticizer and β-cyclodextrin, the early hydration heat rate of TCSA was decreased significantly, which delayed the formation of ettringite. Meanwhile, the density of the product was improved due to the reduction of water consumption, thus achieving the effect of normal setting time, suitable fluidity and high mechanical strength. Moreover, the cement has good frost resistance.