Effects of Blast Furnace Slag Powder and Limestone Powder on the Mechanical Properties and Durability of Shotcrete Using Monocalcium Aluminate Setting Accelerator

• Published in: Materials Vol. 15; no. 7; p. 2495
• Main Authors: Kang, Bonghee, Kim, Gyuyong, Lee, Taegyu, Koo, Kyungmo, Lee, Sangkyu, Son, Minjae, Sasui, Sasui, Eu, Hamin
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 28-03-2022; MDPI
• Subjects: Admixtures; Blast furnace slags; Calcium aluminate; calcium aluminate accelerator; Cement; cement hydration; Chloride ions; Composite materials; Compressive strength; Concrete mixing; Diffusion coefficient; durability; Evaluation; ground granulated blast-furnace slag; Hydration; Limestone; limestone powder; Mechanical properties; Mixing ratio; Mortars (material); Penetration resistance; shotcrete; Slag; Sprayed concrete; cement hydration; ground granulated blast-furnace slag; shotcrete; calcium aluminate accelerator; limestone powder; durability
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15072495

In this study, the effect of fine blast furnace slag powder (SP) and limestone powder (LSP) as a mineral admixture in shotcrete using monocalcium aluminate (CA) as a quick-setting accelerator was evaluated. The shotcrete was prepared with up to 25 wt.% substitutions of mineral admixture, i.e., (SP and LSP), and then the CA accelerator was incorporated by 5 wt.% of binders. To examine the optimal mixing ratio for mineral admixture in shotcrete, penetration resistance, compressive strength, XRD analysis, and MIP analysis were performed on the mortar. On the other hand, compressive strength test, chloride diffusion coefficient, and freeze-thaw resistance were conducted on concrete to evaluate the field applicability of shotcrete. The study revealed the addition of LSP improved setting time and early compressive strength while the addition of SP increased long-term compressive strength. With the addition of both SP and LSP, the early and long-term strength was increased due to the influence of the properties of each admixture. Furthermore, the addition of SP and LSP improves the resistance of shotcrete to chloride ions and freeze-thaw.