Performance and Hydration Mechanism of Modified Tabia with Composite-Activated Coal Gangue

Yanbing Zhao,Bokun Wang,Zhiren Wu,Caiqian Yang,Songlin Cheng

doi:10.3390/cryst12020150

Yanbing Zhao, Bokun Wang + Show 3 more

Open Access

https://doi.org/10.3390/cryst12020150

Copy DOI

Abstract

The feasibility of modified tabia (MT) with composite-activated coal gangue (CACG) as the subgrade material of low-grade highways was experimentally investigated. A composite activation method was employed to improve the pozzolanic activity of coal gangue. The effect of CACG content on the mechanical properties of MT was investigated through a series of experiments. It was found that the pozzolanic reactivity of coal gangue was remarkably enhanced by the composite activation method. Compared with traditional tabia (TT), the unconfined compressive strength, splitting strength, and flexural tensile strength of the MT with 50% of CACG content increased by 5.03 times, 9.71 times, and 1.50 times, respectively. The impermeability of specimens with CACG significantly improved. Furthermore, the mass loss rate of MT was less than 2.83%, while it reached up to 34.20% in TT after being conditioned to 40 freeze–thaw cycles. Finally, the microstructure change and hydration mechanism of MT are discussed and revealed.

Highlights

The feasibility of modified tabia (MT) with composite-activated coal gangue (CACG) as the subgrade material of low-grade highways was experimentally investigated
This paper proposes a modified tabia technology with composite-acti2 of 19 vated coal gangue (CACG) to enhance the subgrade performance of low-grade highways around coal mines
This paper proposes a modified tabia technology with composite-activated

Summary

Introduction

The feasibility of modified tabia (MT) with composite-activated coal gangue (CACG) as the subgrade material of low-grade highways was experimentally investigated. A composite activation method was employed to improve the pozzolanic activity of coal gangue. Qiu et al [6] investigated the influence of calcined coal gangue content on the mechanical behavior of cement mortar. Zhao et al [7] proposed that coal gangue can be employed as a primary cementitious material after being modified by an activation method. Huang et al [8] investigated the effect of the coal gangue replacement ratio as the coarse aggregate on the concrete properties of concrete subjected to freeze-and-thaw cycles. Few investigations have concentrated on the feasibility of employing coal gangue to improve the subgrade performance of low-grade highways

Methods

Results

Conclusion