Effect of strontium slag on early hydration and mechanical properties of belite-C4A3$ cement

Abstract

Belite-calcium sulfoaluminate (Belite-C4A3$) cement is one type of low-calcium clinker with good long-term compressive strength and durability. Yet, its early mechanical property is lower than P·І 42.5. In this paper, the effect of strontium slag on the preparation and performance of belite-C4A3$ cement was investigated. Moreover, the effect of SrO on crystal form and hydration characteristic of silicate minerals was studied. It was found that SrO could improve the early hydration activity of silicate minerals by stabilizing the β-type C2S and M-type C3S. The experiment results showed that the addition of strontium slag improved the burnability of cement, stabilized the high temperature active crystalline form of silicate minerals and promoted its formation, which were benefited to the rapid generation of hydration products and increase of early compressive strength of belite-C4A3$ cement. It was found that the compressive strength of belite-C4A3$ cement at different ages was increased to various degrees under the content of 1∼8% strontium slag. The optimal content of strontium slag was 5%, and its compressive strength of 1, 3, 7 and 28 days was 8.43, 35.83, 71.25 and 103.73 MPa, respectively. Compared with the blank group without strontium slag, the compressive strength was increased by 270%, 210%, 320% and 13%, respectively. This indicated that strontium slag had a significant effect on improving the early mechanical properties of belite-C4A3$ cement.