Off-the-road Research Articles

Developing thermal insulation cement-based mortars using recycled carbon black derived from scrapped off-the-road tires

This study appraised the feasibility of recycled carbon black (RCB) derived from scrapped off-the-road (OTR) tires, denoted as RCB-OTR, as aggregates to develop thermal insulation mortars. Sand in Ordinary Portland cement (OPC)-based mortars was replaced by RCB-OTR in volumetric proportions of 0, 30, 60, and 100%. The results revealed that the developed thermal insulation mortars had oven-dry densities between 1058 ± 1 and 2045 ± 5 kg/m3 and 28-day UCS between 8.6 ± 0.74 and 37.3 ± 0.76 MPa. Mortars at RCB-OTR replacement ratios below 30% can be employed as load-bearing units. Replacing all sand with RCB-OTR resulted in a considerable decrease in thermal conductivity from 1.800 ± 0.071 to 0.272 ± 0.021 W/mK, the volumetric heat capacity from 1.438 ± 0.063 to 1.044 ± 0.079 MJ/m3K, and thermal diffusivity from 1.255 ± 0.089 to 0.263 ± 0.034 mm2/s. Overall, mortars mixed with RCB-OTR exhibited good thermal insulation performance and satisfactory mechanical properties, demonstrating that RCB-OTR is a promising lightweight aggregate for thermal insulation building materials. This is the first study to incorporate RCB-OTR into the cement-based materials and evaluate the thermal properties. It contributes to the development of eco-friendly thermal insulation building materials using RCB-OTR and delivers an innovative solution for mining industry to dispose of waste OTR tires.

Effects of site operating conditions on real site TKPH (tonne-kilometer-per-hour) of ultra-large off-the-road tires

The objective of this study is to investigate the effects of site operating conditions on the real site TKPH (tonne-kilometer-per-hour) of ultra-large off-the-road (OTR) tires. To achieve this, a novel finite element OTR tire thermal (OTRTire-T) model was developed to predict the temperatures of OTR tires. As per the results from the OTRTire-T model, the cycle length coefficient K1and the site ambient temperature coefficient K2were refined and then compared with existing coefficients in the literature for cross-verification. After cross-verification, these K1and K2coefficients were used to calculate the real site TKPHs. The real site TKPHs were investigated under different site operating conditions (i.e. average vertical tire loads, average cycle speeds, ambient temperatures, and cycle lengths). The results showed that the real site TKPH increased with a rise in average cycle speeds from 10 to 45 km/h and an elevation of ambient temperatures from −30°C to 40°C. At low ambient temperatures below 15°C, as per the real site TKPH, the loading capacity of the truck may increase (compared with its rating payload of 363 t) at mine sites. In addition, the real site TKPH increased relatively rapidly when the cycle lengths were short but rose slowly, or even leveled off, with a further increase in cycle lengths.

Numerical Investigation of Temperatures in Ultra-Large Off-the-Road Tires Under Operating Conditions at Mine Sites

Abstract The objective of this study is to conduct a numerical investigation to examine the temperatures in off-the-road (OTR) tires under operating conditions at mine sites. To achieve this, a new mathematical equation was developed based on a modified Mooney–Rivlin (MR) strain energy function, the pseudo-elasticity theory, and the inverse analysis method. This equation was used to determine the internal heat generation rates of tire rubbers. With heat generation rates, the governing equation of heat conduction and the mathematical expression of boundary conditions were further generated to describe the heat transfer in tire rubbers. Based on these equations, a novel finite element (FE) OTR tire thermal (OTRTire-T) model was developed. This OTRTire-T model was used to numerically investigate temperatures in OTR tires at vertical loads from 0.34 to 1.04 MN, hauling speeds from 5 to 30 km/h, and ambient temperatures from −30 to 40 °C. The results showed that a large vertical load (e.g., 1.04 MN) increased the tire rubber temperatures considerably. Tire rubber temperature also increased with an increase in hauling speeds, and the increase became more significant at larger vertical loads (e.g., 1.04 MN). The OTRTire-T model identified an inverse proportional relationship between the rubber temperature increments and the ambient temperatures from −30 to 40 °C. Nonetheless, the rubber temperature in the OTR tire increased relatively rapidly with an increase in ambient temperatures.

Review on National Competitive Advantage for Marketing Potentials for Off-The Road (OTR) Tyre Industry in Sri Lanka

Among countless number of products manufactured around the world certain countries have developed highly competitive positions in the global market for certain products. This case study looks into the national competitive advantage of nations through the Porters diamond model and investigates how countries could develop leading position in a product facing the fierce global competition. Sri Lanka being the world’s largest solid tyre manufacturer, the country has great potential to develop in the much larger off the road tyre segment. A country being situated in a region where an industry cluster is strong has proven to give the country higher potential success in the particular industry. Further Asia’s newly industrialized countries starting from similar positions to Sri Lanka held competitive positions in the apparel industry. However, the economic development shifted their national competitive advantage to other more industrialized sectors including the tyre industry. Sri Lanka as a country featured with national advantages in rubber sector should look into shifting our national competitive advantage to other industries where tyre industry is a highly potential candidate. The review on the said content has been presented in this paper followed by a literature-based discussion as the main research instrument. Paper discusses the main concepts and related justifications on national competitive advantages by referring to accepted models and empirical review. It has concluded the main points whilst encouraging future research works to examine the ways and means to expand the marketing potential of Sri Lankan rubber industry.

A novel phenomenological model for predicting hysteresis loss of rubber compounds obtained from ultra-large off-the-road tires

The objective of this study was to develop a novel phenomenological model that can predict the hysteresis loss of rubber compounds obtained from ultra-large off-the-road (OTR) tires under typical operating conditions at mine sites. To achieve this, first, cyclic tensile tests were conducted on tire tread compounds to derive the experimental results of hysteresis curves, peak stress, residual strain, and hysteresis loss at 6 strain levels, 8 strain rates, and 14 rubber temperatures. Then, referring to these experimental results, a phenomenological model was developed – the HLSRT model (a hysteresis loss model considering strain levels, strain rates, and rubber temperatures). This HLSRT model was generated based on a novel strain energy function that was modified from the traditional Mooney-Rivlin (MR) function, and the model was used to predict the hysteresis loss of rubber compounds in OTR tires. The prediction results show that the HLSRT model estimated the hysteresis loss of tire tread compounds with average and maximum mean absolute percent errors (MAPEs) of 11.2% and 18.6%, respectively, at strain levels ranging from 10% to 100%, strain rates from 10% to 500% s−1, and rubber temperatures from −30°C to 100°C. These MAPEs were relatively low when compared with previous studies, showing that the HLSRT model has higher prediction accuracy. For the first time, the HLSRT model derived from this study has provided a new approach to predicting the hysteresis loss of OTR tire rubbers to guide the use of OTR tires in truck haulage at mine sites.

Morphological and Mechanical Properties of Thermoplastic Elastomers Based on Recycled High Density Polyethylene and Recycled Natural Rubber

Abstract In this work, thermoplastic elastomers (TPE) are produced by melt mixing of recycled high-density polyethylene (RHD) with two types of off-the-road (OTR) ground tire rubber (GTR). Non-regenerated (NR) and regenerated (RR) rubbers are used to investigate the effect of GTR concentration and regeneration on the blends properties containing up to 90 wt.% GTR. The blend morphology is studied by scanning electron microscopy (SEM) to show incompatibility and low interfacial adhesion between RHD and GTR (NR and RR) especially above 40 wt.% RR. This behavior is attributed to the GTR regeneration process and agglomeration of RR particles with lower surface area and affinity toward RHD compared with NR. In all the compounds, the mechanical properties in tension of RR blends were lower than for NR blends, which is attributed to the degradation of the GTR backbone chains lowering the molecular weight (MW) during the regeneration process. Also, NR has a more important effect on impact strength improvement due to its higher crosslinked structure making the particles more deformable/elastic to absorb the mechanical energy before crack initiation. The experimental results also show that 80 wt.% GTR is the optimum concentration for the production of low cost and eco-friendly TPE based on recycled materials.

Hysteresis loss of ultra-large off-the-road tire rubber compounds based on operating conditions at mine sites

The objective of this study is to investigate the hysteresis loss of ultra-large off-the-road (OTR) tire rubber compounds based on typical operating conditions at mine sites. Cyclic tensile tests were conducted on tread and sidewall compounds at six strain levels ranging from 10% to 100%, eight strain rates from 10% to 500% s−1 and 14 rubber temperatures from −30°C to 100°C. The test results showed that a large strain level (e.g. 100%) increased the hysteresis loss of tire rubber compounds considerably. Hysteresis loss of tire rubber compounds increased with a rise of strain rates, and the increasing rates became greater at large strain levels (e.g. 100%). Moreover, a rise of rubber temperatures caused a decrease in hysteresis loss; however, the decrease became less significant when the rubber temperatures were above 10°C. Compared with tread compounds, sidewall compounds showed greater hysteresis loss values and more rapid increases in hysteresis loss with the rising strain rate.

Compressibility characteristics of TDA from OTR (off-the-road) tires: A numerical approach

This paper aims to use the discrete element method (DEM) to study the performance of discarded off-the-road (OTR) tire chips under compression. The results of small-scale laboratory tests were used to calibrate a model built in PFC3D. This model was validated using the results of a large-scale laboratory experiment. The results show that the discrepancy between the calculated strain and the strain measured in the laboratory was 1.94%. Furthermore, the calculated elastic modulus was 0.11 MPa lower than the elastic modulus determined in laboratory measurements. A sensitivity analysis done on the parameters included in the simulation indicated that Poisson’s ratio and the local damping ratio had a significant impact on the simulation results, whereas the loading rate, particle size and scale effect of the loading cylinder had a limited effect on the simulation results. The compressibility characteristics of OTR tire chips in the field embankment were simulated using a cuboid filled with the same size clumps as the TDA chips used in laboratory tests, and the simulation results were compared with available information. The results indicated that the parameters calibrated based on the small-scale laboratory tests can be used to predict the deformation of OTR tire chips in the field. The discrepancy between the calculation and field measurements for strain was 1%. Due to the extremely low winter temperatures in Edmonton (as low as −40 °C), the impact of temperature on the mechanical properties of OTR tire chips was also considered by varying the values of elastic modulus used in the simulation. The results show that the tire chip embankment had a larger strain in summer than in winter as a result of the high elastic modulus in warmer temperatures; however, the difference between the summer and winter strain values is only 0.4%. This paper presents valuable results on the deformation characteristics of OTR tire chips, using a combination of field measurements and laboratory measurements, and exploring the impact of temperature on the deformation of OTR chips using a numerical approach.

Increasing the Brand Awareness of PT. Banmadju Mandiriperkasa’s Customers Through A Company Profile Video

PT. Banmadju Mandiriperkasa is located at Jl. Pattimura 104b, Kediri. As a tyre retreading company, the main product of PT. Banmadju Mandiriperkasa are both hot and cold retreading systems. Meanwhile, the company also offers a complete tyre sizing for each category of a vehicle from sedan, minibus, bus, truck, forklift, and also OTR (Off the Road). The company’s main problem is the intense competition between the competitors in the global retread tyre market, which causes PT. Banmadju Mandiriperkasa should increase brand awareness to the customers. Therefore, it is better to make a company profile video as a solution to overcome the company’s problem. To gain awareness from the potential customer, the company profile video will be distributed by using social media such as WhatsApp, Instagram, Facebook, and YouTube. By having a company profile video, PT. Banmadju Mandiriperkasa can increase the brand awareness to the potential customers from all over Indonesia. Keywords: retreading company, tyre, awareness, company profile video, potential customers.

Stubble resistance of rubber vulcanizates: Influence of short fiber and resin

Stubble resistance of tread rubber vulcanizate of a tyre is crucial, especially for the off-the road (OTR) tyres. However, it has not been vividly discussed in the literature. Here, we developed a test method for stubble resistance, and studied the effect of short aramid fibre and two different types of resins on the stubble resistance of a conventional tire tread recipe with a view to its improvement. Resin filled compositions, being flexible, showed better cut initiation resistance, as compared to aramid fibre filled stiffer compositions, by dissipating the stress through chain orientation. During penetration, both cut growth and frictional force were important. For the aramid fibre composition, the frictional force dominated, whereas the cut growth was predominant for the resin filled vulcanizates. How the different energies associated with the fracture, e.g. cut initiation and growth energies, frictional energy and total fracture energy, altered with respect to the modulus or elongation at break of the rubber vulcanizates has also been discussed. At 4–6 phr of aramid filler concentration, stubble resistance drastically improved. On the other hand, the resin at 4 phr concentration exhibited an overall improvement in stubble resistance as compared to the conventional recipe. In summary, the present work contributed to the effect of different parameters on the stubble resistance of a tire tread rubber vulcanizate using an inhouse developed new test method.

FEM Optimization of a Steel Belt of OTR Tyres

This paper deals with an FEM simulation of a steel belt of tyres. A belt is a part of a tyre that plays a very important role in all radial tyres especially in case of heavy-duty off-the-road (OTR) ones. It is a composite composed of rubber material and a steel reinforcement. High peak stress inside this composite can initiate cracks, which subsequently lead to a complete tyre failure. In this work, the belt is extracted from the tyre and simulated separately in order to be able to cover individual cords. Belt behaviour under tension is studied and optimal cord distribution is proposed to decrease the risk of the failure. FEM software MSC Marc/Mentat is employed as a calculation tool.

Rotomolding of Thermoplastic Elastomers Based on Low-Density Polyethylene and Recycled Natural Rubber

In this study, regenerated and nonregenerated off-the-road (OTR) ground tire rubber (GTR) was blended with low-density polyethylene (LDPE) to produce thermoplastic elastomers (TPE) by rotational molding. In particular, blending was performed by two different methods: melt blending (extrusion) and dry blending (high shear mixer). Then, different GTR concentrations (0, 20, 35, and 50 wt %) were used to determine the effect of rubber content on the processability and properties of the rotomolded compounds. From the samples produced, a complete morphological (optical and scanning electron microscopy), physical (density and hardness), and mechanical (tension, flexion, and impact) characterization was performed. The results showed that increasing the rubber content decreased the mechanical rigidity and strength but increased the elasticity and ductility. Finally, although melt blending led to slightly better properties than dry blending, the latter is more interesting to limit possible material degradation (mechanical, thermal, and oxidative), while reducing processing cost and time.

Reverse logistics network design for large off-the-road scrap tires from mining sites with a single shredding resource scheduling application

The mining industry is one of the world’s massive scrap off-the-road (OTR) tire generators. Reverse logistics (RL) allows for a cost-effective treatment of residual items with environmentally friendly practices. This paper aims to design a RL network for large OTR tires discarded from scattered mining sites, which requires a substantial initial investment in tire downsizing equipment. Therefore, the on-site use of a single shared shredding resource set is proposed with a schedule of visits between mines. Our contribution is a mixed-integer linear programming model set to determine the OTR tires optimal network, including decisions regarding a tire-fuelled power plant location, tire shredding and transport amounts, and a shredding resource set schedule to maximize the profits of the RL network while considering whole waste tire stockpile limits per year. Results showed that the proposed RL network starting from mine shredding tires and supplying a power generation plant might be a profitable solution that could help mines to comply with the legal regulations and turn this waste into a positive economic value good. Environmental and social implications are the mitigation of scrap tires, an increased job demand triggered by power plants, and public health improvement in the vicinity of the mining sites.

Reducing mining footprint by matching haul fleet demand and route-oriented tire types

Off-The-Road (OTR) tires represent an important part of the operational costs of the mining industry. Each year, a typical operation consumes hundreds of tires. In general worn and damaged tires are not reused and represent a major issue for mining sustainability. In terms of operational costs, tires are only second to fuel, translating into several USD millions per year for an average mine operation. In addition, tires affect equipment performance and availability and, consequently, put at risk the capacity of the haul fleets to deliver the production targets.OTR tire lifespan depends on proper type selection. Each tire-type implies choosing a combination of rubber compounds and geometric specifications that are suited to road parameters. Medium and long term mining plans specify routes and production goals. In general, each route has a specific optimal tire type. The traditional approach is to consider the most demanding conditions and selecting a single tire type for the whole fleet. In such a way, truck dispatch is flexible as any truck can haul on any route. A drawback is that this one-size-fits-all policy increases tire consumption as the worst-case route sets the type of tire for the entire fleet.The above builds an interesting case for optimizing tire selection and haul fleet usage schedule as both decisions can be relevant in search for reducing tire consumption, decrease operational costs, and assure production plan adherence. As tire type may influence haul cycle times, assignment of trucks to different routes should also be considered. This work introduces a novel methodology for setting a usage allocation plan for the haul fleet and selecting route-oriented tire types.We test our methodology using a medium size open-pit operation in northern Chile. The case study shows a tire consumption reduction of 7.3% with respect to the traditional approach over a 5 year time span. Net present tire costs are reduced by USD 2.7 millions (−7.2%). Our methodology presents a novel approach to both reducing costs and achieving long-term production plans.

Field Evaluation of Load-Bearing Capacity of Tire Fill Embankment Pavements

Abstract Tire-derived aggregates (TDAs) are produced by shredding scrap tires. These materials have desirable engineering properties and can be appropriately used in pavement embankment fills. Several pavements have been constructed using TDA fill embankment; however, the seasonal performance of the pavements composed of these materials has not been widely investigated. This study investigates seasonal changes in load-bearing capacity of tire-filled embankment pavements after two years of construction in comparison to conventional pavement in a test road in Edmonton, Alberta, Canada. Three sections were constructed using different TDA materials, including passenger and light-truck tires (PLTT), off-the-road (OTR) tire particles, and a mix of PLTT and local subgrade soil, which was placed adjacent to a conventional section that acted as a control section. Falling weight deflectometer (FWD) tests were conducted in different seasons, and the back-calculation results revealed that although the subgrade of the TDA sections showed higher deflection and a lower resilient modulus compared with the control section, the load-bearing capacity of the TDA sections was greater than that for the control section. The section constructed using a mix of TDA material and soil showed almost the same performance as the control section.

Forecasting of a Thermal Condition of Pneumatic Tires of Dump Trucks

Over the last 10 years the world consumption of coal has grown almost by 50%. Coal is one of the main energy resources capable to satisfy basic energy demands of increasing population and developing world economy. On January 24, 2012 the long-term Coal Industry Development Program for the period till 2030 was approved in Russia. According to this Program coal mining in Kuzbass in 2030 will make 260 million tonns of coal per year. Development of the coal industry is impossible without upgrade of coal production by avoiding inefficient technological, organizational and economic solutions. Off the road (OTR) tires play an important role in ensuring effective, continuous and safe work of mining motor transport.

Performance Evaluation of Highway Embankment Constructed from Tire-Derived Aggregate Using Falling Weight Deflectometer Tests

To evaluate the performance of tire-derived aggregate (TDA) for use as highway embankment fill material, a test embankment was constructed in Edmonton, Alberta, Canada. The test embankment was 80 m in length and contained four different test sections, each 20 m in length. The four test sections consisted of embankment material made from passenger and light truck tires (PLTT), off-the-road (OTR) truck tires, TDA-soil mixture, and soil without TDA. The performance of the test embankment was evaluated using falling weight deflectometer (FWD) tests following the placement of each pavement layers (subgrade, base course, and asphalt). FWD deflection data measured at different times for a year, and backcalculated moduli and deflection basin parameters, such as maximum deflection (Do), base layer index (BLI), middle layer index (MLI), and lower layer index (LLI) computed from the deflection data suggest that a TDA fill with a design similar to that used in this study would perform satisfactorily as highway fill.

Finite-Element Analysis of Highway Embankment Made from Tire-Derived Aggregate

Tire-derived aggregate (TDA) has been used in many civil engineering applications. Despite its successful use in the past, the amount of experimental research available on TDA applications is not sufficient to provide data for the evaluation of an appropriate constitutive model. The majority of TDA constitutive models have been developed from laboratory tests performed on tire chips smaller than those used in field applications. In this study, nonlinear elastic material models, with an elastic modulus that varies as a function of vertical stress, have been developed for TDA produced from passenger and light truck tire (PLTT) and off-the-road (OTR) vehicle tires. The material model for TDA is established based on previous large-scale laboratory constrained compression tests conducted on TDA up to 300 mm in size. The model is used in a finite-element (FE) analysis using geotechnical software to predict the settlement of full-scale test embankment during construction. The results indicate that the settlements obtained from the FE analysis agree with the settlements measured in the field during construction of full-scale test embankment. This paper also provides design charts to compute overbuild required on top of TDA layer(s) to compensate immediate compression under an applied load during the placement of cover on top of TDA.

On the compressibility of tire-derived aggregate: comparison of results from laboratory and field tests

Compression behavior of tire-derived aggregate (TDA) was investigated through relatively small-scale and large-scale laboratory one-dimensional compression tests, as well as a full-scale field test. Two types of TDA produced from passenger and light truck tire (PLTT) and off-the-road (OTR) tire were tested. The influence of initial void ratio (e0), particle size, tire source, and testing method on the compression behavior of TDA was investigated. The results indicated that the compressibility of TDA was primarily dominated by its e0. OTR yielded lower e0 than PLTT with similar particle size and the same compaction method. TDA in the field was pre-compressed by self-weight, resulting in lower e0 and compressibility compared with laboratory samples. At relatively high stress levels, all TDA exhibited similar void ratio–stress curves regardless of e0, particle size, tire source or testing method. High e0, small particle size, and granular particle shape facilitated the sliding and rolling of TDA particles, resulting in high plastic strain. The elastic deformation of TDA, reflecting the elastic behavior of tire rubber, was primarily dominated by the average contact area ratio of the TDA particles, depending mainly on the sample void ratio.

Investigation of tire derived aggregate as a fill material for highway embankment

This study investigates the compression behavior and performance of tire derived aggregate (TDA) used to construct an 80-m long embankment for a highway test road in Edmonton, AB, Canada. The road contained four test sections made from passenger and light truck tires (PLTT), off-the-road (OTR) truck tires, TDA–soil mixture, and native soil. A total of 30 temperature probes and 25 settlement plates were embedded into the road to monitor the embankment. Falling Weight Deflectometer (FWD) test was also conducted under different load levels to determine the embankment material’s deflection behavior after the placement of the soil cover. Through observation, field data, and FWD testing, it was determined that PLTT is more compressible than OTR and the TDA–soil mixture, and TDA–soil mix section showed equivalent performance with the control section. Additionally, all the temperature probes revealed no internal heating during the 8-month monitoring period.