Mode of innovative green production for concrete engineering: life cycle assessment of accelerators prepared from aluminum mud wastes.

Abstract

In this study, two types of liquid alkali-free accelerators were prepared by aluminum sulfate (AF1) and aluminum mud wastes (AF2), and the life cycle assessment (LCA) in the preparation of AF1 and AF2 was compared. The LCA was considered from cradle to gate including raw materials used, transportation, and accelerator preparation based on the method ReCiPe2016. The results indicated that AF1 had a higher environmental impact in all midpoint impact categories and endpoint indicators than that of AF2, and AF2 reduced 43.59% emission of CO2, 59.09% emission of SO2, 71% consumption of mineral resources, and 46.67% consumption of fossil resources than that of AF1 respectively. As an environment-friendly accelerator, AF2 had a better application performance than traditional accelerator AF1. When the dosage of accelerators was 7%, the initial setting times of cement pastes containing AF1 and AF2 were 4 min 57 s and 4 min 04 s respectively, the final setting times of cement pastes containing AF1 and AF2 were 11 min 49 s and 9 min 53 s respectively, and the compressive strengths at 1 d of mortars containing AF1 and AF2 were 7.35 MPa and 8.33 MPa respectively. This study aims to provide technical feasibility and environmental impact assessment for exploring new avenues of preparing environment-friendly liquid alkali-free accelerators with aluminum mud solid wastes. It has great potential in reducing carbon and pollution emissions and has a greater competitive advantage due to great application performance.