Powder Characteristics and Cementitious Properties of Steel Slag Used as Supplementary Cementitious Materials

Abstract

Powder characteristics and granule morphology of steel slag cooled by water-quenching and air splashing were observed with SEM and their rest angle, compressed density and mechanical characteristics were measured. The result shows that particle sphericity of air splashing steel slag is lower than that of water-quenching steel slag. A compressive stress has a more effective on the deaggregation of water-quenching steel slag powder. Both of the two steel slag powders are typical Coulomb powder. Compared with the water-quenching steel slag powder, air splashing steel slag powder has a higher internal friction angle and cohesiveness. The cementitious activity of BOFS Powder can only meets the standard of the second grade powder according to the Chinese National Standards.

Feasibility of Preparing Steel Slag–Ground Granulated Blast Furnace Slag Cementitious Materials: Synergistic Hydration, Fresh, and Hardened Properties

“…However, if the content of cement is too high, it can actually decrease the strength of the system. This is because when there is an excess amount of cement, the concentration of Ca 2+ in the early solution quickly reaches saturation, making it difficult for it to react with GBFS in a timely manner, impeding the dissolution of calcium aluminate and calcium silicate in steel slag [75][76][77].…”

“…In experiments conducted by You et al [47], when water glass is used as an alkaline activator, the 1 d and 28 d compressive strength of alkali-activated Providing an alkaline environment directly is the easiest way to improve the mechanical properties. Research has shown that several commonly used alkaline activators have different stimulating effects on SGM, with water glass having the best effect, followed by NaOH, Na 2 SO 4 , and Na 2 CO 3 having the worst effect [34,77]. When water glass is used as the alkaline activator, the 28 d compressive strength can reach 76.6 MPa thanks to the dual stimulation of OH − and [SiO 4 ] 4− .…”

“…The mass loss is only 1.1% and the frost resistance reaches the F300 level. Li et al [77] compared the durability of alkali-activated steel slag material with Portland cement and found that the frost resistance of alkali-activated steel slag cementitious materials was better than that of Portland cement. The compressive strength loss rate and mass loss rate of alkali-activated steel slag cementitious materials after 50 freeze-thaw cycles are 5.9% and 1.03%, respectively, lower than the values of 9.6% and 1.11% for Portland cement.…”