Engineering properties of cementless concrete produced from GGBFS and recycled desulfurization slag

This study used the byproducts of steel manufacturing, ground granulated blast furnace slag (GGBFS) and desulfurization slag (DS), to produce cementless concrete. Superplasticizers (SP) were added to improve the higher water absorption of DS and enhance the compressive strength of cementless concrete. The feasibility of manufacture was evaluated by the engineering properties of slump, setting time, compressive strength, length change, sulfate attack resistance and scanning electron microscopy (SEM) analysis. The results showed that 14 MPa could be obtained with the addition of 550 kg/m3 of GGBFS. The compressive strength and sulfate attack resistance of the cementless concrete were enhanced as the amount of added SP was increased, and the length change did not exceed 0.05% within 90 days, indicating good volume stability. SEM showed that the main hydration products were ettringite, calcium hydroxide, and tobermorite gel during the early stage of hydration, which gave the cementless concrete its early strength.