Granular Matter (2018) 20:29 https://doi.org/10.1007/s10035-018-0804-3 ORIGINAL PAPER An experimental investigation on the durability of railway ballast material by magnesium sulfate soundness Ekin Köken 1 · Ahmet Özarslan 1 · Gürkan Bacak 2 Received: 26 January 2018 © Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract In this study, the durability of railway ballast material is investigated by magnesium sulfate soundness tests. Two types of ballast aggregates, which are produced from basaltic rocks and currently used as railway ballast in such high speed railway routes in Turkey, are investigated regarding their resistance against freezing–thawing (FT) and traffic loads. Firstly, the mineralogical and physico-mechanical properties of rocks are determined. Then the degradation of investigated ballast aggregates is determined by magnesium sulfate soundness and Los Angeles abrasion (LAA) tests. The natural FT effects are simulated by magnesium sulfate soundness tests up to 40 cycles, whereas the traffic loads are represented by LAA tests up to 3000 revolutions. The ballast fouling that leads to such problems are also investigated within the scope in the present study. The degree of ballast fouling is quantified as fouling index (FI) which is determined using the crushed particles generated after LAA tests. It is concluded from laboratory studies that rock properties considered are considerably influenced by simulated FT cycles. It is also achieved from the laboratory studies that magnesium sulfate soundness and Los Angeles abrasion tests are good indicators to clarify the fragmentation mechanism of the ballast aggregate in laboratory scale. In conclusion several empirical formulas are developed to predict LAA and FI for each rock type. The proposed empirical formulas could be utilized as a pre-design tool for new railway routes in design stage provided that the investigated ballast aggregates are considered. Keywords Railway ballast material · Aggregate · Simulated FT cycles · Magnesium sulfate soundness · Los Angeles abrasion · Ballast fouling 1 Introduction High speed railways have recently become widespread throughout the world, as rail is acknowledged the most eco- nomic and emissions-efficient mode of transportation [1]. The quality of railway ballast plays a key role in terms of satisfying the stability of railway route, since the axle loads have increased with increasing the speed of trains. When con- structing a substructure layer for any railway route, the most important issues are to maintain settlements of top ballast layer within acceptable limits, attenuate the loads acting on rails and sleepers and facilitate surface water drainage [2,3]. This statement necessitates a well-constituted substructure B Ekin Köken ekin.koken@beun.edu.tr 1 Mining Engineering Department, Bulent Ecevit University, Zonguldak, Turkey 2 Geological Engineering Department, Bulent Ecevit University, Zonguldak, Turkey layer (i.e. a combination of top ballast, subballast and sub- grade layer). If the quality of ballast is not satisfactory (i.e. use of poor quality ballast material), problems will be encountered for the ballast layer, rails and sleepers. For instance, the ballast aggregates with poor quality may easily be disintegrated by traffic loads and environmental factors. Because of that rea- son, the transmission of loads acting on concrete sleeper and rail is not desired as planned [4–6]. In addition to this, the ballast layer may be contami- nated by organic matter (i.e. action of plants) that causes fouling, piping and drainage problems [7–10]. Another note- worthy point occurs if the ballast layer is at an inappropriate thickness. If the thickness of ballast layer is more than the optimized thickness, compaction problems take place dur- ing tamping. On the other hand, when it is thinner than the optimized thickness, the transmission of the loads acting on sleepers is not as desired [11]. Apart from the thickness of ballast layer, the strength of ballast aggregate, traffic loads and environmental conditions 0123456789().: V,-vol 123