Exploring the effect of calcium sulfoaluminate cement on the hydration and degree of reaction of slag cement

초록

This study investigates the hydration properties of ternary blended binders composed of Portland cement (PC), calcium sulfoaluminate cement (CSA) and blast furnace slag (BFS). Paste samples with 50% BFS and varying PC-to-CSA ratios were cured for up to 360 d and characterized using various analytical techniques. The results indicate that incorporating 10% CSA enhances the degree of reaction (DOR) of alite and BFS after 28 d of curing, despite its early-age retarding effect. At 360 d, the 10% CSA sample increased the BFS DOR from 55% (in the 0% CSA sample) to 65%, improved compressive strength from 63 MPa to 70 MPa, and reduced porosity from 37% to 32%. These improvements are attributed to ettringite destabilization and secondary nucleation of C-A-S-H, promoting efficient pore filling. However, higher CSA replacements were detrimental to the DOR of alite and BFS. In conclusion, CSA cement can be used as a viable partial substitute for PC to enhance the DOR of both PC and BFS, which contributes to improved long-term strength of the blended system.

키워드