Abstract
As a massive solid waste, the high value-added utilization of coal gangue has received more and more attention in China. This study focuses on the utilization of coal gangue aggregate in railway engineering for coal transportation passage. Coal gangue aggregate was employed as high-grade railway subgrade filler andprepared concrete for roadbed drainage (named coal gangue roadbed protecting concrete—CGRPC). First, the basic properties of coal gangue such as particle size distribution, ignition loss, strength change under water softening, and compression performance were measured. Then, the technology to use coal gangue as filler in railway subgrade was put forward based on a real engineering application with the Jingang coal-carrying railway special line. Field tests showed that the coal gangue roadbed had excellent performance. The dynamic stiffness expressed as K30 was more 130 MPa/m, which meets the requirement for high-speed railway roadbeds. The distribution of vertical earth pressure according to the backfill depth showed a linear growing tendency. Finally, the technical and economic benefits of using coal gangue railway roadbeds were analyzed. The application of coal gangue near the railway line not only solved the problem of aggregate shortage in engineering construction, but it also consumes the coal gangue waste and leads to huge social benefits.
Highlights
Coal gangue is normally seen as an industrial solid waste, and it is widely distributed in coal mining areas, such as northwest China or Newcastle (Australia)
Zhang et al [11] demonstrated that coal gangue is suitable for use as a lightweight aggregate in construction materials, its practical application is still relatively limited because concrete compressive strength requirements limit its usage as an aggregate
It was found that about 35.4% strength reduction would be produced by the transition from the dry statTeabtloe t2h. eThseatcuhreamteicdal sctoamtep.oAsitfitoenrstoefsthinegratwhemcartuersihalesdfoirnCdGexRPoCf. the coal gangue and comparing it to the limestone (Figure 3c), Zezhou coal gangue was found to have the larger index, whichMmaTetehtretiahles or below 30%
Summary
Coal gangue is normally seen as an industrial solid waste, and it is widely distributed in coal mining areas, such as northwest China or Newcastle (Australia). Coal gangue is a type of shale rich in minerals and has a similar hardness to gravel It can be used as aggregate in concrete and subgrade fillers. Thanks to the development of sustainability technology, coal gangue has been widely recycled in construction [1,2], power plants [3], agriculture [3,4,5], and backfills [6] This mineral has the properties of natural aggregate and contains organic substances and can spontaneously combust [7,8]. Bricks do not have the same strict requirements regarding compressive strength In this way, coal gangue can be utilized as fillers in roadbed construction. From the perspective of the later railway construction, the positive social effects from this practical project could promote this coal gangue utilization technology
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