Enhancement in compressive strength of foamed concrete by ultra-fine slag. (April 2023)

• Record Type: Journal Article
• Authors: Li, Maogao; Tan, Hongbo; He, Xingyang; Jian, Shouwei; Li, Guangyan; Zhang, Junjie; Deng, Xiufeng; Lin, Xiaoli
• Is Part Of: Cement & concrete composites. Volume 138(2023)
• Publication Date: 2023-04
• Subjects: Foamed concrete -- Enhance skeleton -- Ultra-fine slag -- Pore structure -- Strength; Composite-reinforced concrete -- Periodicals; Concrete -- Periodicals; Composite materials -- Periodicals; Composites de ciment -- Périodiques; Béton -- Périodiques; Composites -- Périodiques; Béton léger -- Périodiques; Cement composites; Composite materials; Composite-reinforced concrete; Concrete; Lightweight concrete; Periodicals; Electronic journals; 620.135
• DOI: 10.1016/j.cemconcomp.2023.104954
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: In this study, ultra-fine slag (UFS) was used to prepare foamed concrete by replacing Portland cement (PC) to enhance the compressive strength of foamed concrete. PC-UFS system was designed and the replacement ratio of UFS to cement was 10%, 20%, 30% and 40%. The compressive strength at the age of 7 d, 14 d and 28 d were measured, and the fluidity was evaluated. The hardness of PC-UFS foamed concrete was characterized by nanoindentation test. The related mechanism was researched by XRD, TGA, SEM and 29 Si-NMR, and pores structure was analyzed by X-ray micro-computed tomography. Results exhibited that the compressive strength of PC-UFS foamed concrete was higher than that of PC foamed concrete, noting that the 7 d and 28 d compressive strength of S0 (0% UFS) was 4.46 MPa and 6.99 MPa, and that of S40 (40% UFS) reached to 5.59 MPa and 7.75 MPa, with an increase by 25% and 11%. The reason was that UFS showed a great filling and particle grading effect, and it was also found that UFS accelerated the formation of C-A-S-H gel and densified the microstructure. Moreover, adding UFS decreased the average diameter and the diameter distribution of the pores. Such results proposed a novel method to improve the mechanical properties of foamed concrete.