Pre-treatments of MSWI bottom ash for the application as supplementary cememtitious material in blended cement paste

Author(s): Boyu Chen (1), Yubo Sun (1), Loic Jacquemin (1), Shizhe Zhang (1), Kees Blom (2)Mladena Luković (3) Guang Ye
Paper category: Proceedings
Book title: Proceedings of the International Conference on Sustainable Materials, Systems and Structures (SMSS2019) New Generation of Construction Materials
Editor(s): Marijana Serdar, Nina Štirmer, John Provis
ISBN: 978-2-35158-217-6,
Vol 1. ISBN: 978-2-35158-223-7
e-ISBN: 978-2-35158-218-3
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 211-217
Total Pages: 7
Language : English

Abstract: At present, most municipal solid waste incineration (MSWI) bottom ash, as being disposed of as waste, is directly landfilled, raising concern about the environmental issue and potential loss of resources. Given that the natural raw materials used for cement production are being depleted, the recycling of MSWI bottom ash for the application as building materials is meaningful and promising. The feasibility of using MSWI bottom ash as mineral additives in concrete has been demonstrated in the literature. In this research, as-received MSWI bottom ash has high mineral content and shows stable leaching behaviour. But, when used as cement substitute, the residual metallic Al in bottom ash always causes matrix swelling and strength loss by reacting with Ca(OH)2 and releasing H2 gas. In this research, dry and wet pre- treatment methods were performed to remove the metallic Al in as-received bottom ash (0- 2mm). The results show that both of these two methods are effective. When comparing these two methods, wet method is time-consuming but can remove the metallic Al completely; dry method is fast but always has limitation that it can only reduce the metallic Al content by 80%. Regarding compressive strength, the decrease introduced by 10% dry-treated bottom replacement in cement paste is less than that of wet-treated bottom ash. The lower strength development observed in wet-treated bottom ash blended cement may be due to the removal of soluble reactive phases during the treatment.

Online publication : 2019
Publication type : full_text
Public price (Euros) : 0.00