Research On Preparation Of High Reactive Mineral Admixture Composed Of Steel Slag

As a by-product generated during steel-making,steel slag(SS)is a kind of potential resource.The amount of steel-making in China is 50% of the world,but the usage of SS is only 10%.How to use it reasonably becomes an issue about resource and environment.Using SS as a supplementary mineral admixture is an effective way because of its composition similar to cement,but CxS of mineral admixture is less than that in clinker of cement,which results in lower reactivity than cement.The paper is designed to heighten the reactivity of SS and products of SS.To get the higher reactivity of SS,the thesis systematically research on preparing the activity of different places and pretreatment methods.As the SS without any thermal treatment,the reactivity can be enhanced by mixing adjusting materials and high temperature composite technology.Try to use SS to make aerated concrete blocks(ACB).The results of experiments show that,in the age of 28 d,the reactivity of hot carbon steel slag is lower than rotating drum steel slag.The 28 d reactivity index of rotating drum steel slag C is 99.7%,which is the highest,while the lowest 28 d reactivity index of SS W is 74.2%.The analysis of XRD shows that C2 S and C2 F in hot carbon steel slag is less than that in rotating drum steel slag.The results of orthogonal experiments under cool condition illustrate that in the age of 3d,the reactivity index of SS-GBFS-cement system is up to 81%,while in the age of 28 d up to 102.6%.The fluidity of mixture groups is better than cement group,and the maximumfluidity is 224 mm.The influence of system alkalinity to system activity of early age is negligible,while in the age of 28 d,the bigger is system alkalinity,the higher is system activity.The results of SS-FA-cement experiments indicate that the reactivity index in the age of 3d is 82.2%,and in the age of 28 d,it reaches 91.3%.The reactivity index of SS-GBFS-FA-cement is up to 81.6% and 91.0% in the age of 3d and 28 d,respectively.On the basis of the proportion with 1.5% Na2 Si O3 and 1.5% Ca O,the reactivity index of the system attains 84.2% and 104.7% in the age of 3d and 28 d.On the condition of high temperature,the flexural strength of SS system in the age of 3d is 4.22 MPa,while in the age of 28 d up to 8.15 MPa.Compared with Si and Si-Al,Ca is more suitable for mixing in the system.When the amount of mixture is 50%,the preparation procedure of SS contributes more than Si and Si-Al to the bending strength.It's attainable that the reactivity index of Ca system in the age of 3d is 62.3%,and in the age of 28 d is 104.1%.Replace 40% FA with SS W to make ACB with the mix of N1 and N2,and the compressive strength of blocks can reach 3.83 MPa.The compressive strength of blocks of B3(1.5%N1)is up to 3.83 MPa,while C2(0.4%N2)is 2.98 MPa.Compared with the reference samples,the dry density of the sample mixing activator changed from B06 to B05,indicating that mixing activator possess a better effect.