Innovative Cement‐Free Alkali‐Activated Concrete: A Study on Ultra‐Rapid Hardening under Negative Temperature Curing Condition

Abstract Conventional silicate cement is difficult to use in extremely cold regions. But alkali‐activated slag concrete (AASC) can use alkali‐activated chemistry to accelerate the production of C‐A‐S‐H cementitious materials, resulting in high mechanical properties in a short period of time. In this paper, it investigated the static mechanical properties of alkali‐activated slag concrete with different CaO contents and insulation methods under low‐temperature conditions (‐15 °C). It was shown that when the CaO content was 2%, the flexural strength of the concrete with a curing time of only 4h was 9.20 MPa, the compressive strength was 47.6 MPa. Both in the fully wrapped insulation method and the upper and lower wrapped insulation method could be used in low temperature conditions. The flexural strengths of both methods were 9.90 MPa and 8.93 MPa in 4 h. Their compressive strengths were 59.1 MPa and 66.53 MPa, respectively. Therefore, AASC can achieve ideal strength at low temperatures. It is a building material that can be used under extreme conditions.