An experimental investigation on the durability of railway ballast material by magnesium sulfate soundness

Köken E. | Özarslan A. | Bacak G.

Article | 2018 | Granular Matter20 ( 2 )

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 sulfa . . .te 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. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature Daha fazlası Daha az

Durability of concrete incorporating non-ground blast furnace slag and bottom ash as fine aggregate

Yüksel I. | Bilir T. | Özkan O.

Article | 2007 | Building and Environment42 ( 7 ) , pp.2651 - 2659

The paper presents investigation of how the usage of bottom ash (BA), granulated blast furnace slag (GBFS), and combination of both of these materials as fine aggregate in concrete affects the concrete durability. To assess durability characteristics of concrete, durability tests were conducted and the results were evaluated comparing with reference concrete. Three series concrete were produced. GBFS, BA and GBFS+BA are replaced the 3-7 mm-sized aggregate. Five test groups were constituted with the replacement percentages as 10%, 20%, 30%, 40% and 50% in each series. These by-products were used as non-ground form in the concrete. Du . . .rability properties of the concretes were compared in order to study the possible advantages of different replacement ratios. According to results, GBFS and BA affects some durability properties of concrete positively in case of it is used as fine aggregate. Resistance to high temperature and surface abrasion are positively affected properties. Capillarity, drying-wetting and freezing-thawing resistance of the concrete can be accepted to some extent. Properties of by-products and its replacement ratio are controlling the influence level and direction. Comparison of the SEM images and test results show that chemical and physical properties of GBFS and BA are the main factors affecting the concrete durability. It is concluded that it is possible to produce durable concrete by using GBFS and BA as fine aggregate. © 2006 Elsevier Ltd. All rights reserved Daha fazlası Daha az

An experimental investigation on rock crushability using jaw and cone crushers

Köken E. | Bilen M. | Özarslan A. | Baris K.

Conference Object | 2019 | IMCET 2019 - Proceedings of the 26th International Mining Congress and Exhibition of Turkey , pp.734 - 743

This study covers the investigation of rock crushability using laboratory-scale cone and jaw crushers for five types of hardrocks. For this purpose, physico?mechanical properties of the investigated rocks are determined. Aggregate samples with a particle size range of 10.00 - 14.00 mm are prepared for crushability tests. After performing crushability tests, crushed particles are sieved and considering sieve analysis results, crushability indices are identified for each rock and crusher type. The performance of the crushers concerning their experimental setup is investigated by Taggart method. It is achieved from crushability tests t . . .hat, the performance of the cone crusher is approximately two times better than the one of the jaw crusher for their experimental setups. The crushing time (Tc) seems to increase with increasing in rock strength properties. Furthermore, remarkable relationships are obtained between several rock properties and crushability test results. It can be claimed that crushability of rocks are dependent upon crusher type, setup of crushing process, rock strength as well as the mineral hardness. Considering these types of variables, higher achieving benefits of aggregate production could be satisfied at lower costs. Copyright © IMCET 2019 International Mining Congress and Exhibition of Turkey. All rights reserved Daha fazlası Daha az

Effect of aggregate type on mechanical properties of reactive powder concrete

Aydin S. | Yazici H. | Yardimci M.Y. | Yigiter H.

Article | 2010 | ACI Materials Journal107 ( 5 ) , pp.441 - 449

This paper focuses on the experimental study of the mechanical properties of reactive powder concrete (RPC) produced with different aggregates, such as korund, basalt, limestone, quartz, sintered bauxite, and granite. The effects of aggregate type on mechanical properties were investigated under standard, atmospheric, and high-pressure steam curing. The test results indicate that very high compressive strength can be achieved even with low-strength or smooth-surface aggregates; however, superior flexural performance requires high-strength aggregate with rough surface characteristics. A compressive strength of approximately 200 MPa ( . . .29 ksi) can be obtained when strong and rough-surface textured aggregate were used under standard curing conditions. Atmospheric and high-pressure steam curing improved the compressive strength significantly. These curing regimes, however, did not considerably improve the flexural performance. Pressure application in fresh state resulted in a great improvement of the compressive strength of RPC, particularly in the case of high-strength and rough-surface textured aggregates. In this way, a compressive strength over 400 MPa (58 ksi) was obtained with bauxite aggregate after pressure application and autoclaving. Copyright © 2010, American Concrete Institute. All rights reserved Daha fazlası Daha az

Usage of industrial by-products to produce plain concrete elements

Yüksel I. | Bilir T.

Article | 2007 | Construction and Building Materials21 ( 3 ) , pp.686 - 694

This paper describes the results of research aimed at studying the possible usage of bottom ash (BA) and granulated blast-furnace slag (GBFS) in production of plain concrete elements. Sufficient number of briquettes, paving blocks and kerbs specimens containing GBFS and BA as fine aggregate replacement were produced in laboratory. Then, some of tests were conducted for investigating durability and mechanical properties of these specimens. Unit weight, compression strength and freeze-thaw tests were conducted for briquette specimens. Compression strength, freeze-thaw, water absorption and surface abrasion tests were conducted for pav . . .ing blocks. Surface abrasion and flexural tensile strength tests were conducted for kerb specimens. While compression strength was decreased slightly, durability characteristics such as resistance of freeze-thaw and abrasion were improved. The results showed that usage of partially fine aggregate of these industrial by-products has more beneficial effects on durability characteristics of plain concrete elements. © 2006 Elsevier Ltd. All rights reserved Daha fazlası Daha az

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