Effects of Steel Slag Powder Content and Curing Condition on the Performance of Alkali-Activated Materials Based UHPC Matrix

Abstract

The accumulation of steel slag and other industrial solid wastes has caused serious environmental pollution and resource waste, and the resource utilization of steel slag is imminent. In this paper, alkali-activated ultra-high-performance concrete (AAM-UHPC) was prepared by replacing ground granulated blast furnace slag (GGBFS) powder with different proportions of steel slag powder, and its workability, mechanical properties, curing condition, microstructure, and pore structure were investigated. The results illustrate that the incorporation of steel slag powder can significantly delay the setting time and improve the flowability of AAM-UHPC, making it possible for engineering applications. The mechanical properties of AAM-UHPC showed a tendency to increase and then decrease with the increase in steel slag dosing and reached their best performance at a 30% dosage of steel slag. The maximum compressive strength and flexural strength are 157.1 MPa and 16.32 Mpa, respectively. High-temperature steam or hot water curing at an early age was beneficial to the strength development of AAM-UHPC, but continuous high-temperature, hot, and humid curing would lead to strength inversion. When the dosage of steel slag is 30%, the average pore diameter of the matrix is only 8.43 nm, and the appropriate steel slag dosage can reduce the heat of hydration and refine the pore size distribution, making the matrix denser.

Mechanical Performance Optimization and Microstructural Mechanism Study of Alkali-Activated Steel Slag–Slag Cementitious Materials

“…The active silica and alumina content in steel slag is lower than that in slag, and the addition of steel slag will theoretically reduce the compressive strength of the sample. However, this study found that the addition of suitable steel slag can improve the strength to a certain extent, and Song et al [42] and Shi et al [43] also reached the same conclusion. The presence of this phenomenon is due to the high content of insoluble materials, primarily calcium carbonate, within the steel slag.…”

Physical, Mechanical and Structural Characteristics of Sulfur Concrete with Bitumen Modified Sulfur and Fly Ash

“…Such types of waste include waste from the fuel and energy complex and waste from gas and oil plants. For example, with regard to the use of fuel and energy complex waste in construction technology, there are many works on the use of fly ash [4][5][6][7][8][9], slag [10][11][12][13][14][15] and microsilica [16][17][18][19][20][21][22]. As for gas and oil production, the main types of waste are oil sludge, spent proppant and sulfur.…”