Performance of Recycled Concrete Made from Railway Sleeper: Experimental Study

Concrete railway sleeper has been used in Indonesia since about 1990�s. It has more advantage that is less maintenance, stabile, good quality, shapeable, onsite raw material, and higher loading ability [9-10, 20 - 22]. But It is prone to damage such as cracking and breaking during construction, so it is often thrown away as a solid waste that can contaminate the land and reduce soil fertility. Therefore, it should be utilized in order to be more useful that is used as recycle aggregate. The concrete waste that is taken from broken concrete railway sleeper will be crush as an aggregate as raw material in the concrete to substitute part or all of the normal concrete. It is called recycled aggregate and concrete that is made from recycled aggregate is called recycled concrete. Base on the testing of raw material, the recycled aggregate can be met to the specification as ASTM [1], so it can be used for concrete raw material. Recycled concrete compressive strength result lower the normal concrete compressive strength in the same initial strength design. The strength value of recycled concrete is decrease about 1 � 17% for 25 MPa and 10 � 18% for 30 MPa. It is also happened to tensile strength of recycled concrete that decrease about 2 � 13 % for 25 MPa and 7 � 22 % for 30 MPa.

Full-Scale Field Experimental Investigation on the Intended Irregularity of CWR Track in Vertical Plane

The purpose of the following paper is to present the author’s experimental field investigations of a jointless railway track subjected to a generated imperfection and analysis of track response to applied static loads. An optical measurement system, Pontos, was used for the static and dynamic analysis of the track’s deflections in 3D. The investigations allow us to recommend a direct application of this system for the non-contact measurement, visualization and analysis of simulated defects in the jointless track, as presented by the author. It is stated that simulation of an effect called the hanging sleeper, a short irregularity in the railway track with the initial parameters provided (a gap and a length of irregularity), is possible. The proposed method, based on the measurement in the loaded track (a static load from the locomotive wheels), allows for a description of the effect of the changing track support condition. Moreover, it also proves its usefulness for the analysis of the changes in deflection and stress values and the force transferred from the rail on the railway sleeper and for the assumed shape of defects simulating the short irregularities arising in the operated railway track. The arising irregularity in the track affects driving comfort and the safety of travellers.

WOOD-GLASS-FIBER COMPOSITE MATERIALS BASED ON POLYESTER RESINS FOR TIMBER RAILWAY SLEEPER STRUCTURES

Wood-glass-fiber composite materials (WGFCM) are used in transport construction (sleepers, switch bars, etc.). Polymer solutions based on furfuralacetone monomer (FAM) served as a matrix for the manufacture of WGFCM. The article suggests using Holex HAS- 2061 polyester resin as a matrix, which, in turn, has chemical resistance, dielectric properties, increased impact strength, having sufficient strength characteristics, and significant extensibility. For the application of the above material in the structural elements of sleepers of logging railways, it is necessary to know its operation under repeated loading. Endurance experiments were conducted at different coefficients of the load application cycle asymmetry pb=0,1; 0,3; 0,6. As a result of the experiments, the values of the endurance limit of the material under study were obtained, which allow us to conclude that it can be used in the construction of timber railway sleepers.

Novel Bending Test Method for Polymer Railway Sleeper Materials

Alternative sleeper technologies have been developed to address the significant need for the replacement of deteriorating timber railway sleepers. The review of the literature indicates that the railway sleepers might fail while in service, despite passing the evaluation tests of the current composite sleeper standards which indicated that these tests do not represent in situ sleeper on ballast. In this research, a new five-point bending test is developed to evaluate the flexural behaviour of timber replacement sleeper technologies supported by ballast. Due to the simplicity, acceptance level of evaluation accuracy and the lack of in-service behaviour of alternative sleepers, this new testing method is justified with the bending behaviour according to the Beam on Elastic Foundation theory. Three timber replacement sleeper technologies—plastic, synthetic composites and low-profile prestressed concrete sleepers in addition to timber sleepers—were tested under service loading condition to evaluate the suitability of the new test method. To address the differences in the bending of the sleepers due to their different modulus of elasticities, the most appropriate material for the middle support was also determined. Analytical equations of the bending moments with and without middle support settlement were also developed. The results showed that the five-point static bending test could induce the positive and negative bending moments experienced by railway sleepers under a train wheel load. It was also found that with the proposed testing spans, steel-EPDM rubber is the most suitable configuration for low bending modulus sleepers such as plastic, steel-neoprene for medium modulus polymer sleepers and steel-steel for very high modulus sleepers such as concrete. Finally, the proposed bending moment equations can precisely predict the flexural behaviour of alternative sleepers under the five-point bending test.

Behaviour of Polymer Filled Composites for Novel Polymer Railway Sleepers

A novel concept of polymer railway sleeper is proposed in this study that has the potential to meet static performance requirements within the cost of hardwood timber. The existing challenges of composite sleepers, such as low performance or high cost, can be overcome using this innovative concept. Such a proclamation is proven through limit state design criteria and a series of experimentations. Results show that polyurethane foam as an infill material can provide sufficient strength and stiffness properties to the sleeper, but the inadequate screw holding capacity could be a problem. This limitation, however, can be overcome using a particulate filled resin system. The findings of this study will help the railway industry to develop a timber replacement sleeper.

Machine learning-aided identification of train weights from railway sleeper vibration

Within the UK and many other countries, the weight of a train is a critical factor in determining how much the train operator must pay to use the railway network. This study explores the use of different machine learning algorithms to predict the weight of a train based on the vibration signals recorded in a railway sleeper. The vibration signals are split into two groups: time-domain and frequency-domain signals. Then, different algorithms are developed for each group, to see which domain offers the best representation of a vibration signal for use within models to determine target values. From the study, it can be seen that machine learning has the potential to predict the weight of a train effectively. This insight can lead to the use of mobile sensors in practice, such as the application of wireless accelerometers connected with a smartphone, to help engineers audit and provide assurance of the train access integrity.

Quality Control of Pre-stressed Concrete Sleepers in Sudan Railways

Nowadays, railway transport plays a very important role in the transport system in a period of positive growth of commerce, economy and industry. In accordance with other modes of transport, railway is the most stable mode for transporting, safety, capability carrying, social and economic benefits. Sleepers have major roles in the complex railway system and distributed the load from rails when train goes through to the ballast. This study discussed pre-stressed concrete sleepers in Sudan railways and compare them with other varies of sleepers taken in consideration the service life, handling, weight of sleeper, damage, suitability for fastening and vibration resistance. On the other side explained the manufacturing stages that sleepers undergoes and the quality control accompanying them. A numerical static analysis for a pre-stressed concrete mono-block railway sleeper is carried out using finite element package named "ANSYS 15". Using SOLID65 solid element, the compressive strength of concrete is facilitated using plasticity algorithm while the concrete cracking in tension zone is accommodated by the nonlinear material model. Since the section of concrete sleeper is fully pre-stressed by nature, the smeared crack analogy is impracticable. Discrete reinforcement modeling with truss elements, LINK8, is then more suitable to utilize. Perfect bonding is presumed herein between concrete and pre-stressing wires. Thus, the results of the analysis that evaluate the effect of cables in deformed shape, strains, stress of pre-stressed concrete sleepers are compared to the solid concrete sleepers. Therefore, the insight into static behaviors will not only result in a safer and more reliable design method for railway infrastructure, but it can also translate and apply to other civil concrete structures.