Freeze–thaw resistance of alkali–slag concrete based on response surface methodology: Fid-Bau Portal

Freeze–thaw resistance of alkali–slag concrete based on response surface methodology

Cai, Liangcai / Wang, Haifu / Fu, Yawei

Highlights • Response surface methodology (RSM) is used to study ASC’s freeze–thaw resistance. • The influence on the freeze–thaw resistance from high to low is A/S, slag content and sand ratio. • The interaction of A/S and slag content is the most prominent. • Air-void structure is a decisive factor, and space coefficient and specific surface area are related well to D F.

Abstract Alkali–slag concrete (ASC), with the frost resistant grade of above F300 and frost resistant coefficient D F of about 90%, is prepared using slag and composite activator composed of Na2SiO3 and NaOH. Response surface methodology (RSM) is applied to study the freeze–thaw resistance of ASC. The effects of activator solution–slag ratio (A/S), slag content and sand ratio on the freeze–thaw resistance are analyzed using the softwares of Design Expert and Box-Benhnken Design (BBD). Models are established for D F and the influence of air-void structure of hard concrete on the freeze–thaw resistance, respectively. The result shows that the D F model coincides well with the test results and can be used to analyze and predict the freeze–thaw resistance of ASC. The influence on the freeze–thaw resistance from high to low is A/S, slag content and sand ratio. The interaction of A/S and slag content is the most prominent and air-void structure is the crucial factor. The air bubble space coefficient and its specific surface area have good correlation with D F. The freeze–thaw resistance tends to better with smaller air bubble space coefficient and bigger specific surface area.