Synthesis and characterization of one-part alkali-activated grouting materials based on granulated blast furnace slag, uncalcined coal gangue and microscopic fly ash sinking beads. (22nd August 2022)

• Record Type: Journal Article
• Authors: Xu, Cheng; Zhang, Zhengqi; Tang, Xiuming; Gui, Zengjian; Liu, Feifei
• Is Part Of: Construction & building materials. Volume 345(2022)
• Publication Date: 2022-08-22
• Subjects: GBFS granulated blast furnace slag -- CG coal gangue -- UCG uncalcined coal gangue -- MFASB microscopic fly ash sinking beads -- OAGM one-part alkali-activated grouting material -- W/S ratios water to solid ratios -- ASM anhydrous sodium metasilicate -- BR borax -- AAMs alkali-activated materials -- EDTA-4Na tetra sodium ethylene diamine tetra acetate -- IDS tetrasodium iminidisuccinate -- XRD X-ray diffraction -- FTIR Fourier transform infrared spectroscopy -- SEM scanning electron microscopy -- EDS energy dispersive X-ray -- MIP mercury intrusion porosimetry -- XRF X-ray fluorescence -- MPD medium pore diameter -- APD average pore diameter -- RH relative humidity; One-part alkali-activated grouting materials -- Granulated blast furnace slag -- Uncalcined coal gangue -- Microscopic fly ash sinking beads -- Borax -- Flowability -- Setting time -- Compressive strength -- Microstructure; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2022.128254
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: GBFS, UCG and MFASB were used to synthesis the ternary OAGM. Effects of various factors on flowability, setting time and strength were studied. Borax is the optimal retarder for the ternary OAGM. The ternary OAGM with BR has high compressive strength and great flowability. Reaction product, microstructure and pore structure of different OAGMs were studied. Abstract: To obtain an environment-friendly grouting material suitable for in situ application, the granulated blast furnace slag (GBFS), uncalcined coal gangue (UCG) and microscopic fly ash sinking beads (MFASB) were used to synthesis the one-part alkali-activated grouting material (OAGM). Firstly, OAGMs with different combination of precursors were prepared respectively, which are GBFS-based OAGM (the unitary OAGM), GBFS/UCG-based OAGM (the binary OAGM) and GBFS/UCG/MFASB-based OAGM (the ternary OAGM). The flowability, setting time and compressive strength of them were measured to analyze their applicability and feasibility in grouting engineering and obtain the OAGM with a reasonable combination of precursors. Next, the effects of different water to solid ratios (W/S ratios), different retarders, and the content of selected retarder on the OAGM were investigated to put forward its rational composition under the best overall performance. Finally, the reaction product, microstructure and pore structure of OAGMs were characterized to probe into their mechanism. Results show that compared with other OAGMs, the ternary OAGM with the retarder borax (BR) has the best overall performance. This material not only has the best flowability and the longest setting time, but also has high compressive strength, thus, it is more suitable for grouting engineering. Microstructural tests reveal that adding UCG and MFASB sequentially into GBFS-based OAGM makes important impacts on the formation of C-A-S-H gel, thus affecting the compressive strength. And adding MFASB into the binary OAGM increases the harmless pores, causing the ternary OAGM has higher porosity. However, the increase of porosity does not necessarily bring about the decrease of compressive strength. Besides, pore structure characteristics shows that adding BR increases the porosity of the ternary OAGM. This study can provide guidance for preparing environment-friendly OAGM suitable for in situ application and promote the recycling of industrial solid wastes.