Preparation and Performance of a Low-Carbon Foam Material of Fly-Ash-Based Foamed Geopolymer for the Goaf Filling.

Lijuan Su,Jianing Zhang,Baoxin Jia,Guangchun Yao,Yunlong Wang,Guosheng Fu,Xinchao Xu

doi:10.3390/ma13040841

Lijuan Su, Jianing Zhang + Show 5 more

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https://doi.org/10.3390/ma13040841

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Journal: Materials	Publication Date: Feb 12, 2020
Citations: 7	License type: CC BY 4.0

Affiliation: Liaoning Technical University, Northeastern University

Abstract

The treatment of goaf subsidence is important for sustainable development. Geopolymer is a new type of cementing material with excellent mechanical properties, durability, corrosion resistance, and other advantages owing to its unique three-dimensional spatial aggregation structure. Herein, a type of preparation technology of fly-ash-based foamed geopolymer suitable for goaf filling was developed by adding a chemical foaming agent to the matrix of fly-ash-based geopolymer. The mechanical properties, chemical composition, and pore structure characteristics of the samples were discussed. When the samples with different contents of fly ash, sodium metasilicate, sodium stearate, H2O2, and NaOH were prepared, a uniaxial compression test was performed to analyze the uniaxial compression failure characteristics and compression strength of the samples. The mineralogical composition of each sample was analyzed by X-ray diffraction (XRD) test, and the microstructure images of different samples were observed using scanning electron microscopy (SEM). The effects of the content of each component on the properties of the samples were discussed. Finally, the CO2 emission, energy consumption, and cost of producing fly-ash-based foamed geopolymer were analyzed. Overall, the material had the advantages of low energy consumption, low CO2 emission, environmental-protection ability, and waste utilization and thus has a broad application prospect in treating subsidence.

Highlights

With the large-scale exploitation of mineral resources, the problem of goaf subsidence has increasingly become prominent [1,2]
This study aimed to develop a type of foamed geopolymer material for goaf filling
A type of fly-ash-based foamed geopolymer, which is suitable for goaf filling is prepared

Summary

Introduction

With the large-scale exploitation of mineral resources, the problem of goaf subsidence has increasingly become prominent [1,2]. The collapse of the mined out area causes serious damage to the surface ecological environment and a series of geological environmental problems, such as large-scale water accumulation and surface cracking, thereby resulting in great difficulty to the subsequent geological environmental treatment and ecological restoration [3]. This finding is contrary to the introduction of the basic strategy of “insisting on the harmonious coexistence of human and nature”. Developing a green and low carbon filling material for goaf filling is urgent

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Conclusion