Performance and Microstructure of Alkali-Activated Red Mud-Based Grouting Materials Under Class F Fly Ash Amendment
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TECHNICAL NOTE
Performance and Microstructure of Alkali-Activated Red MudBased Grouting Materials Under Class F Fly Ash Amendment Chunjin Lin1 • Wenjie Dai1 • Zhaofeng Li1 • Fei Sha1
Received: 5 January 2020 / Accepted: 5 May 2020 Ó Indian Geotechnical Society 2020
Abstract From the perspective of sustainable development and environmental protection, the environmental friendly substitute of ordinary grouting materials is needed to be proposed. In this paper, we prepared a high-performance and low-cost grouting materials from red mud, granulated blast furnace slag (GBFS) and class F fly ash (FFA). In order to determine the optimal raw materials property, we investigated the effect of FFA dosages on red mud–GBFS grouts system. The results showed that 10% of FFA content could improve the 90-day compressive strength of grouts by 15.4%; fluidity and volume stability were also improved considerably. But when the FFA content is overmuch, it would result in some negative effects, such as longer setting time and higher bleeding rate. According to the mineral phase analysis, the effects of FFA mainly attributed to the physical properties before 28 days, such as ball effect, filling effect and micro-aggregate effect, and the pozzolanic effect of FFA influenced the long-term performance chiefly. Above all the results in this study, the optimum dosage of FFA is 10%. Keywords Class F fly ash Red mud Granulated blast furnace slag Grouting materials Workability Microstructure
& Zhaofeng Li [email protected] 1
Geotechnical and Structural Engineering Research Center, and Civil Engineering School, Shandong University, Jinan 250061, Shandong, China
Introduction In 1980s, mineral polymer with tridimensional structure was proposed by Frenchman Davidovits, and it was formed by polycondensation of aluminosilicates which dissolved in alkaline medium [1]. Geopolymer has excellent engineering performance such as outstanding fire resistance and acid or alkali corrosion resistance, and the geopolymer can obtain a strength as high as cement do with the same solidto-water ratio [2, 3]. In addition, the production of ordinary Portland cement (OPC) per ton at least results in CO2 emissions of 600 kg [4]. In comparison, the production of geopolymer cement per ton only exhausts CO2 of 271 kg [5]. Actually, geopolymer cement was mainly prepared with industrial by-productions such as red mud, GBFS and fly ash [6]. It was conducive to solve the serious environmental problems. The geopolymer was applied into many engineering fields such as tunnel, road, bridge and underground engineering [7–9]. Hence, it was hailed as green and sustainable material. Fly ash is obtained from coal-fired thermal power plants. With the rapid development of power industry, the emissions of fly ash were increased year by year; the effective utilization of fly ash has become a severe challenge [10, 11]. The effect of fly ash on the workability, mechanical strength and long-term performance was studied widely around the world [12, 13]. It was reported by Pan et al
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