Experimental Study of the Mechanical and Microstructure Characteristics of Coal Gangue Road Stabilization Materials Based on Alkali Slag Cementation.

Changbai Wang,Shuzhan Xu,Junxin Yang

doi:10.3390/ma14133601

Abstract

To accelerate the resource utilization of coal gangue and meet the strategic requirements of carbon neutralization, alkali-activated, slag-cemented coal gangue is applied in the preparation of solid waste-based road stabilization materials. Here, the cementation characteristics and microstructure characteristics of alkali-activated, slag-cemented coal gangue road stabilization materials are studied using the alkali equivalent and coal gangue aggregate ratio as experimental variables. The results show that with the increase in alkali equivalent from 1% to 7%, the unconfined compressive strength of the alkali-activated coal gangue road stabilization material initially increases and then decreases, with 3% being the optimal group in terms of stabilization, the aggregate ratio of coal gangue increases from 70% to 85%, and the 7-day unconfined compressive strength of the stabilized material decreases approximately linearly from 8.16 to 1.68 MPa. At the same time, the porosity gradually increases but still meets the requirements of the specification. With the increase in hydration time, a large number of hydration products are formed in the alkali slag cementation system, and they are closely attached to the surface of and interweave with the coal gangue to fill the pores, resulting in the alkali slag slurry and coal gangue being brought closer together.

Highlights

Given its huge output and low degree of resource utilization, coal gangue is the main source of industrial solid waste in China, and it has a significant impact on the ecological environment and on mine safety [1,2]
One of the main ways to utilize coal gangue is as a road stabilization material, and this has attracted the attention of many scholars
This paper studies the preparation of solid-waste coal gangue road stabilization materials using alkali-activated slag as the cementing material, and the relationship between different aggregate rates and alkali equivalents, and the mechanical properties and microstructure of the stabilized materials are analyzed

Summary

Introduction

Given its huge output and low degree of resource utilization, coal gangue is the main source of industrial solid waste in China, and it has a significant impact on the ecological environment and on mine safety [1,2]. China has invested a great deal of labor and material resources to deal with key scientific and technological problems, aiming to accelerate the resource utilization of coal gangue [3,4]. There is a large output of coal gangue, its complex composition, low mechanical strength, and limited economic value have led to low utilization and high stockpiles. One of the main ways to utilize coal gangue is as a road stabilization material, and this has attracted the attention of many scholars. The production of cement is a process involving high pollution and energy consumption, which is contrary to the theme of green building materials

Methods

Results

Conclusion