Abstract: In order to improve the utilization rate of steel slag and slag high valueadded and the admixture of steel slag in cementitious materials,the effects on the compressive strength and flexural strength of the composite cementitious materials were investigated based on different steel slagslag admixtures,ratios and different excitation methods of cementitious activity,and the hydration mechanism of the steel slagslag composite cementitious materials were investigated using Xray diffraction,scanning electron microscopy and thermogravimetric analysis and other testing methods.The results showed that when the steel slagslag dosing was 80%,the steel slagslag mass ratio was 5∶5,and the grinding time of steel slag was 80 min (specific surface area was 509 m2/kg),the 28 d flexural strength of the steel slagslag composite cementitious material was 7.3 MPa and the compressive strength was 31.3 MPa.When NaOH,Na2CO3,Na2SO4 and water glass were selected as the excitation agents,only water glass improved the activity of the composite gelling material,and its 28 d flexural strength was 8.4 MPa and compressive strength was 43.0 MPa when the modulus of water glass was 2 and the Na2O equivalent was 4%.Through SEM microscopic morphology and XRD analysis of the gelling hydration products with the addition of water glass,the microscopic morphology was tight and dense,and the generated C—S—H gel,Ca(OH)2 and Aft interweave with each other,which improves the strength of the gelling material.

Key words: steel slag,slag,gelling activity,mechanical activation,chemical inspiration