Effect of pre-drilling, loading rate and temperature variation on the behavior of railroad spikes used for high-density-polyethylene crossties

2016 ◽  
Vol 231 (1) ◽  
pp. 44-56 ◽  
Author(s):  
Ibrahim Lotfy ◽  
Maen Farhat ◽  
Mohsen A Issa
Keyword(s):  
Finite Element ◽  
High Density Polyethylene ◽  
High Density ◽  
Environmental Benefits ◽  
Experimental Program ◽  
Great Promise ◽  
Static Testing ◽  
Plastic Composite ◽  
Track System ◽  
The Usa

Railroad spikes represent a vital component of the rail track system, as they fasten the rail to the supporting crossties. Thus, it is important to understand its behavior and effect on the fastening assembly to mitigate any local failure, which, in turn, could lead to system deterioration or damage. Currently, alternative solutions to the traditional hardwood timber crossties are increasing being adopted by the railroad industry in the USA, with recycled plastic composite crossties being among the available alternatives. Their sustainably, environmental benefits, durability and ease of installation render them an attractive and competitive solution. Several research programs have studied this material and its fastening system in the past; however, additional research is required to fully understand the behavior of these materials and their interactions with the fastening system components. This paper presents an investigation that aims to understand and assess the performance of typical railroad spikes used for recycled high-density-polyethylene crossties. The study encompassed a comprehensive experimental investigation and analytical finite element modeling. The testing program evaluated railroad spikes using static testing methods recommended by the American Railway Engineering and Maintenance-of-Way Association (AREMA) manual. These tests addressed the rail spike pullout and lateral restraint for both screw and cut spikes. Finite element models were constructed and calibrated using the data obtained from the experimental program in order to extrapolate on the experimental results and predict the behavior of full-scale systems beyond the scale of the laboratory. The results observed in this study showed great promise, surpassing all the AREMA recommendations, which highlights the potential of these materials if properly optimized and engineered. Screw spikes exhibited a very good performance, surpassing the minimum recommendations by a significant margin (up to more than 200%) and are thus are highly recommended for future implementation.

Structural Behavior of Rail Fastening System Used for Recycled Plastic Composite Crossties

2015 ◽  
Author(s):  
Ibrahim Lotfy ◽  
Maen Farhat ◽  
Mohsen A. Issa
Keyword(s):  
Finite Element ◽  
Test Methods ◽  
Environmental Benefits ◽  
Experimental Investigations ◽  
Great Promise ◽  
Static Test ◽  
Railroad Industry ◽  
Plastic Composite ◽  
System Components ◽  
Alternative Solutions

Currently, the railroad industry is leaning towards alternative solutions to hardwood timber for crossties applications. This trend is part of an effort to increase train speeds beyond the wooden crossties capacity and minimize the negative environmental effects associated with them. Among the available alternatives are recycled plastic composite crossties. Their sustainably, environmental benefits, durability performance and ease of installation or one to one replacement of timber crossties render them an attractive and competitive solution. Several research programs have studied this material in the past. However, additional research is required to fully understand the behavior of these materials. This study aims to investigate the performance of fastening system used for recycled High Density Polyethylene crossties. The study encompasses comprehensive experimental investigations and analytical finite element modeling. The testing program evaluated each of the fastening system components using static test methods recommended by the AREMA manual. These tests addressed the spike pullout and lateral restraint for both screw and cut spikes as well as the fastening system uplift behavior. Moreover cyclic testing was also conducted on the full system to study the interactions of the fastening system components with the plastic composite crosstie. Finite element models were constructed and calibrated using the experimental data in order to extrapolate on the experimental results and predict different scenarios. The results observed in this study showed great promise highlighting the potential of these material if properly optimized and engineered.

Mechanical Properties and Thermal Conductivity of Coal Ash-Recycled High-Density Polyethylene Composite

2018 ◽  
Vol 06 (01n02) ◽  
pp. 1850002
Author(s):  
Ban M. Alshabander ◽  
Awattif A. Mohammed ◽  
Asmaa Sh. Khalil
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
High Density Polyethylene ◽  
Waste Product ◽  
Construction Materials ◽  
Coal Ash ◽  
High Density ◽  
Plastic Composite ◽  
The Impact ◽  
Recycled Hdpe

In this study, coal ash/recycled plastic composite material was fabricated with post-consumer high-density polyethylene (HDPE) and coal ash particles. The main idea of using coal ash, since it is also a waste product, as reinforcing filler in recycled HDPE is to reduce the cost, develop lightweight and produce environmental-friendly materials. Coal ash/recycled plastic composite have been used in significant applications as construction materials including flooring, landscaping, fencing, railing window framing and roof tiles. Effect of coal ash loading on the mechanical properties and thermal conductivity of coal ash/recycled HDPE composite were determined. It is expected to use waste materials in new field by getting novel composite materials with developed mechanical properties. It was found that coal ash filler indicated significant improvement on the mechanical properties of composites. The results show that the impact decreased tremendously from 57.32 to 15.8[Formula: see text]kJ/m2 with only 30[Formula: see text]wt.% loading of coal ash. The filler increases the elasticity of the material and reduces its ability to absorb deformation energy.

scholarly journals Influence of Backfill Compaction on Mechanical Characteristics of High-Density Polyethylene Double-Wall Corrugated Pipelines

2019 ◽  
Vol 2019 ◽  
pp. 1-24 ◽  
Author(s):  
Hongyuan Fang ◽  
Peiling Tan ◽  
Bin Li ◽  
Kangjian Yang ◽  
Yunhui Zhang
Keyword(s):  
Finite Element ◽  
High Density Polyethylene ◽  
Three Dimensional ◽  
Local Buckling ◽  
Element Model ◽  
High Density ◽  
Model Matching ◽  
Exterior Wall ◽  
Finite Element Software ◽  
Hdpe Pipe

For flexible pipelines, the influence of backfill compaction on the deformation of the pipe has always been the focus of researchers. Through the finite element software, a three-dimensional soil model matching the exterior wall corrugation of the high-density polyethylene pipe was skillfully established, and the “real” finite element model of pipe-soil interaction verified the accuracy through field test. Based on the model, the strain distribution at any position of the buried HDPE pipe can be obtained. Changing the location and extent of the loose backfill, the strain and radial displacement distributions of the interior and exterior walls of the HDPE pipe under different backfill conditions when external load applied to the foundation were analyzed, and the dangerous parts of the pipe where local buckling and fracture may occur were identified. It is pointed out that when the backfill is loose, near the interface between the backfill loose region and the well-compacted region, the maximum circumferential strain occurs frequently, the exterior wall strain is more likely to increase greatly on the region near crown or invert, the interior wall strains increase in amplitude at springline, and the location of the loose region has a greater influence on the strain of the pipe than the size of the loose area.

scholarly journals Flexural Creep Behavior of High-Density Polyethylene Lumber and Wood Plastic Composite Lumber Made from Thermally Modified Wood

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 262 ◽  
Author(s):  
Murtada Abass A. Alrubaie ◽  
Roberto A. Lopez-Anido ◽  
Douglas J. Gardner
Keyword(s):  
Creep Behavior ◽  
Creep Deformation ◽  
High Density Polyethylene ◽  
Creep Compliance ◽  
High Density ◽  
Wood Plastic Composite ◽  
Creep Stress ◽  
Plastic Composite ◽  
Thermally Modified Wood ◽  
Modified Wood

The use of wood plastic composite lumber as a structural member material in marine applications is challenging due to the tendency of wood plastic composites (WPCs) to creep and absorb water. A novel patent-pending WPC formulation that combines a thermally modified wood flour (as a cellulosic material) and a high strength styrenic copolymer (high impact polystyrene and styrene maleic anhydride) have been developed with advantageous viscoelastic properties (low initial creep compliance and creep rate) compared with the conventional WPCs. In this study, the creep behavior of the WPC and high-density polyethylene (HDPE) lumber in flexure was characterized and compared. Three sample groupings of WPC and HDPE lumber were subjected to three levels of creep stress; 7.5, 15, and 30% of the ultimate flexural strength (Fb) for a duration of 180 days. Because of the relatively low initial creep compliance of the WPC specimens (five times less) compared with the initial creep compliance of HDPE specimens, the creep deformation of HDPE specimens was six times higher than the creep deformation of WPC specimens at the 30% creep stress level. A Power Law model predicted that the strain (3%) to failure in the HDPE lumber would occur in 1.5 years at 30% Fb flexural stress while the predicted strain (1%) failure for the WPC lumber would occur in 150 years. The findings of this study suggest using the WPC lumber in structural application to replace the HDPE lumber in flexure attributable to the low time-dependent deformation when the applied stress value is withing the linear region of the stress-strain relationship.

scholarly journals Life-Cycle Assessment of Recycling Postconsumer High-Density Polyethylene and Polyethylene Terephthalate

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Khaled M. Bataineh
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Polyethylene Terephthalate ◽  
High Density Polyethylene ◽  
Greenhouse Gas Emission ◽  
High Density ◽  
Environmental Benefits ◽  
Atmospheric Pollutants ◽  
System Expansion ◽  
Allocation Methods

This study aims to quantify the overall environmental performances of mechanical recycling of the postconsumer high-density polyethylene (HDPE) and polyethylene terephthalate (PET) in Jordan. The life-cycle assessment (LCA) methodology is used to assess the potential environmental impacts of recycling postconsumer PET and HDPE. It quantifies the total energy requirements, energy sources, atmospheric pollutants, waterborne pollutants, and solid waste resulting from the production of recycled PET and HDPE resin from the postconsumer plastic. System expansion and cut-off recycling allocation methods are applied. The analysis has been carried out according to the LCA standard, series UNI EN ISO 14040-14044:2006. A standard unit of output (functional unit) is defined as “one ton of PET flake” and “one ton of HDPE pellet.” The results of the production of virgin resin are compared with the “cut-off” and “system expansion” recycling results. Depending on the allocation methods applied, a nonrenewable energy saving of 40–85% and greenhouse gas emission saving of 25–75% can be achieved. Based on two allocation methods, PET and HDPE recycling offers important environmental benefits over single-use virgin PET and HDPE. LCA offers a powerful tool for assisting companies and policy-makers in the waste plastic industry. Furthermore, the “system expansion” recycling method is not easy to apply because it requires detailed data outside of the life cycle of the investigated product.

Flame retardancy and mechanical properties of thermal plastic composite panels made from Tetra Pak waste and high-density polyethylene

2014 ◽  
Vol 37 (6) ◽  
pp. 1797-1804 ◽  
Author(s):  
Changyan Xu ◽  
Weicheng Jian ◽  
Cheng Xing ◽  
Handong Zhou ◽  
Yuqing Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flame Retardancy ◽  
High Density Polyethylene ◽  
High Density ◽  
Composite Panels ◽  
Plastic Composite ◽  
Tetra Pak
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