Influence Of Steel Slag Grinding Aids On Properties Of Steel Slag-based Cementitious Materials

The mineral composition of steel slag is similar to that of cement.In theory,it can replace cement clinker to prepare cementitious materials.However,because it contains more difficult-to-grind phases such as RO,it causes poor grindability,which reduces the activity of steel slag.In this project,grinding aids are added.The method can improve the grindability of steel slag,reduce grinding energy consumption,and improve the gelling activity of steel slag after grinding.Characterized by specific surface area,sieve allowance and particle size distribution,the effect of different grinding time on the grinding aid of steel slag was carried out without adding grinding aid.The test showed that when the grinding time was 60min,the specific surface area of steel slag was 438m²/kg;the sieve balances of 45μm and 80μm were 24.4%and 7.9%;the content of 3～30μm particle size particles was 45.32%.Six different single-component grinding aids,including triethanolamine,ethylene glycol,glycerol,1,2-propanediol,triisopropanolamine and sodium sulfate,were selected to study the specific surface area,sieve effect of different dosages of grinding aids on steel slag grinding.The influence of residual weight,particle size distribution and flexural and compressive strength,the grinding aid effect is triisopropanolamine>triethanolamine>1,2-propanediol>ethylene glycol>glycerol>sodium sulfate.The single-component grinding aids triethanolamine,ethylene glycol and 1,2-propanediol with good grinding effect were selected to obtain different proportions of composite grinding aids through orthogonal experiments,and the influence of different composite grinding aids on the grinding effect of steel slag was studied.The test shows that the composite grinding aid S2（triethanolamine:ethylene glycol:1,2-propylene glycol=0.05%:0.07%:0.07%）has the best grinding aid effect.The addition of S2increases the specific surface area of the steel slag to 495m²/kg,which is 13.0%higher than that of the blank group.Compared with the blank group,the 3d and 28d flexural strengths were increased by 59.4%and 42.5%respectively.Compared with the blank group,the compressive strength of 3d and 28d was increased by 53.1%and 36.7%,respectively.At the same time,the activity of the steel slag-based cementitious material with the addition of the grinding aid is enhanced,and the activity index of the steel slag-based cementitious material with the addition of the composite grinding aid S2 is 109%.The effect of different grinding aids on the micro-morphological characteristics of the hydration product cementitious materials of the hydration age of the steel slag was studied by XRD,TG,SEM and other test methods.The results showed that the S2composite grinding aid increased Ca（OH）₂in the hydration product of the steel slag-based cementitious material,and reduced the unhydrated particles.At the same time,the microstructure was denser,the inter-structure gap was smaller,and the slurry was more compact.Macroscopically,it shows an increase in strength,indicating that the composite grinding aid has a better grinding effect on steel slag.Figure 19;Table 15;Reference 60...