Journal Article

The synergistic hydration mechanism and environmental safety of multiple solid wastes in red mud-based cementitious materials

Bai, Rong, Zhu, Junge, Yue, Hongzhi, Li, Zichao, Ma, Laijun

2023

Overview

Red mud (RM) is a solid waste material with high alkalinity and low cementing activity component. The low activity of RM makes it difficult to prepare high-performance cementitious materials from RM alone. Five groups of RM-based cementitious samples were prepared by adding steel slag (SS), grade 42.5 ordinary Portland cement (OPC), blast furnace slag cement (BFSC), flue gas desulfurization gypsum (FGDG), and fly ash (FA). The effects of different solid waste additives on the hydration mechanisms, mechanical properties, and environmental safety of RM-based cementitious materials were discussed and analyzed. The results showed that the samples prepared from different solid waste materials and RM formed similar hydration products, and the main products were C–S–H, tobermorite, and Ca(OH) 2 . The mechanical properties of the samples met the single flexural strength criterion (≥ 3.0 MPa) for first-grade pavement brick in the Industry Standard of Building Materials of the People's Republic of China-Concrete Pavement Brick . The alkali substances in the samples existed stably, and the leaching concentrations of the heavy metals reached class III of the surface water environmental quality standards. The radioactivity level was in the unrestricted range for main building materials and decorative materials. The results manifest that RM-based cementitious materials have the characteristics of environmentally friendly materials and possess the potential to partially or fully replace traditional cement in the development of engineering and construction applications and it provides innovative guidance for combined utilization of multi-solid waste materials and RM resources.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Additives / Air pollution control / Alkalinity / Aquatic Pollution / Atmospheric Protection/Air Quality Control/Air Pollution / Blast furnace slags / Bricks / Building materials / Calcium hydroxide / Calcium Sulfate / Cement / class / Coal Ash / Concrete pavements / Construction / Construction materials / Earth and Environmental Science / Ecotoxicology / Environment / Environmental Chemistry / Environmental Health / Environmental quality / Environmental science / Flexural strength / Flue gas / Flue gas desulfurization / Fly ash / furnaces / Gypsum / Heavy metals / Hydration / industry / Industry standards / Leaching / Mechanical properties / Metal concentrations / Metals, Heavy - analysis / modulus of rupture / pavements / people / Pollution control equipment / Portland cement / Portland cements / Quality standards / Radioactivity / Red mud / Research Article / Safety / Slag / Slag cements / slags / Solid Waste - analysis / Solid wastes / Steel / Surface water / Waste materials / Waste Water Technology / Water Management / Water Pollution Control / Water quality