Effect of curing regime on the immobilization of municipal solid waste incineration fly ash in sustainable cement mortar

Baoju Liu; Lei Yang; Jinyan Shi; Shipeng Zhang; Çağlar Yalçınkaya; Abdullah Faisal Alshalif

doi:10.1016/j.envpol.2022.120839

Effect of curing regime on the immobilization of municipal solid waste incineration fly ash in sustainable cement mortar

Environ Pollut. 2023 Jan 15:317:120839. doi: 10.1016/j.envpol.2022.120839. Epub 2022 Dec 6.

Authors

Baoju Liu¹, Lei Yang², Jinyan Shi³, Shipeng Zhang⁴, Çağlar Yalçınkaya⁵, Abdullah Faisal Alshalif⁶

Affiliations

¹ School of Civil Engineering, Central South University, Changsha 410075, China; National Engineering Research Center of High-speed Railway Construction Technology, Changsha 410075, China.
² School of Civil Engineering, Central South University, Changsha 410075, China.
³ School of Civil Engineering, Central South University, Changsha 410075, China. Electronic address: jinyan.shi@csu.edu.cn.
⁴ Department of Civil and Environmental Engineering, Research Centre for Resources Engineering Toward Carbon Neutrality, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
⁵ Department of Civil Engineering, Faculty of Engineering, Dokuz Eylül University, İzmir, Turkiye.
⁶ Jamilus Research Centre for Sustainable Construction (JRC), Faculty of Civil Engineering and Built Environment, Universiti Tun Hussein Onn Malaysia, 86400, Parit Raja, Johor, Malaysia.

PMID: 36493937
DOI: 10.1016/j.envpol.2022.120839

Abstract

Stabilizing/solidificating municipal solid waste incineration fly ash (MIFA) with cement is a common strategy, and it is critical to study the high-value utilization of MIFA in ordinary Portland cement (OPC) components. With this aim, binary-binding-system mortar was produced by partially replacing OPC (∼50%) with MIFA, and the effects of different curing regimes (steam curing and carbonation curing) on the properties of the cement mortar were studied. The results showed that the setting time of the cement paste was shorten with the increase of MIFA content, and steam curing accelerated the hardening of the mixture. Although the incorporation of MIFA reduced the strength of the mortar, compared to conventional curing method, steam curing and carbonation curing increased the 3-d strength of the mortar. For high-volume MIFA mortars, the CO₂-cured samples had the highest long-term strength and lowest permeability. The incorporation of MIFA increased the initial porosity of the mortar, thereby significantly increasing the carbonation degree and crystallinity of the reaction product - CaCO₃. Steam curing also further narrowed the difference in the hydration degree between MIFA-modified sample and plain paste, which may be due to the enhanced hydraulic reactivity of MIFA at high temperatures. Although the incorporation of MIFA increased the porosity of the mortar, this waste-derived SCM refined the bulk pore structure and decreased the interconnected porosity. Additionally, the heavy metal leaching contents of MIFA-modified mortars were all below 1%, which meet the requirements of Chinese standards. Compared with standard curing, steam curing and carbonation curing made the early-age and long-term performance of MIFA-modified mortar better, which can promote the efficient application of MIFA in OPC products.

Keywords: Carbonation curing; Cement mortar; Leaching toxicity; Municipal solid waste incineration fly ash; Sustainability.

MeSH terms

Coal Ash* / analysis
Incineration / methods
Metals, Heavy* / analysis
Solid Waste / analysis
Steam

Substances

Coal Ash
Solid Waste
Steam
Metals, Heavy