Light Truck Tires Research Articles

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.

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.

Compression Behavior of Large-Sized Tire-Derived Aggregate for Embankment Application

Tire-derived aggregate (TDA) has been successfully used for highway embankment applications in the past. Previous applications mainly used small and medium tire sizes as TDA sources. There are no published test results in the literature regarding the compression behavior of TDA made solely from off-the-road tires (OTR). In this study, large-scale, one-dimensional compression tests are carried out to study the compression behavior of TDA from OTR as well as from passenger and light-truck tires (PLTT). Samples for the tests are prepared by varying the initial unit weights. The results show that there is a general trend of decreasing compressibility with increasing initial unit weight for both TDA sources. The compression test results are also used to compare compression behavior between the two TDA sources. It is found that the compression behavior of TDA from OTR and PLTT is more or less similar. Moreover, one-dimensional stress-strain regression equations were developed for TDA from OTR.

Nitrogen Inflation for Passenger Car and Light Truck Tires

Abstract Nitrogen as an inflation gas for passenger car and light truck tires use is widely available commercially. Consumers are confronted with a bewildering selection of offerings, and suppliers tout the purity of their nitrogen generation systems and effectiveness of using the gas in place of air. This paper develops models for the initial tire nitrogen purity, the inflation pressure loss rate, and the evolution of the nitrogen gas purity in the tire as a function of the gas used to top off the tire over its life. A series of simulations using the basic model is developed for air and various purities of nitrogen initial inflation with monthly top-off using air or various purities of nitrogen. The initial inflation pressure loss rate is shown as a function of the tire’s initial nitrogen purity. This paper proposes the use of the total oxygen passing through the tire over its lifetime as a metric for evaluation of various inflation schemes. This metric is developed for several of the popular available nitrogen inflation purities using both air and nitrogen as a top-off gas.

Gas Transport in the Tire Aging Test and Intracarcass Pressure Issues

Abstract Development of the laboratory-based accelerated service life testing—“tire aging test”—encountered difficulties due to the complexity of multidisciplinary processes in the tire materials and structures while trying to induce thermooxidative degradation similar to that taking place in the “worst case” in-service. Preliminary experience with the oven aging at elevated temperatures showed that in some light truck tires damaging conditions occur in the form of sidewall blisters/detachments and casing separations due to inflation gas built up in interior tire layers during oven aging, even prior the roadwheel endurance testing (DOT HS 810 799, Research Report to Congress on Tire Aging), National Highway Traffic Safety Administration (NHTSA), Washington, D.C., 2007, http://www.cbsatlanta.com/download/2010/0512/23529107.pdf). Analysis and comprehensive modeling techniques are developed for gas diffusion and oxidation in the tire structure, with focus on the intracarcass pressure (ICP) build-up predictions. In finite element models, the temperature dependent diffusion properties are used with account for their high heterogeneity in different tire components. Results of transient simulations predict higher oxidation/degradation rate in the sidewall and a detrimental effect of ICP build-up for Load Range E tires—mainly due to excessive nitrogen permeation. Influence of the butyl liner barrier permeability and gauge is evaluated, as well as impact of other tire construction variations. Predicted trends agree with the available observations and measurements. ICP levels in simulations of the long-term gas diffusion under regular service conditions are significantly lower than in the oven aging test modeling. Mechanical aspects of the ICP-induced sidewall separation are also discussed. Modified aging test conditions are proposed that will greatly reduce the deleterious side-effect of the ICP buildup, as assessed in simulations.

Effect of ground rubber powder and devulcanizates on the properties of natural rubber compounds

AbstractGround rubber powder (GRP) and devulcanized rubber (Dev.R) waste through a continuous shear‐flow reaction were used as fillers for virgin natural rubber. A Horikx plot and the gel fraction proved that both main‐chain scission and crosslink scission occurred during the devulcanization. The cure characteristics, swelling behavior, crosslink density, and mechanical properties were studied. GRP and Dev.R, generated from passenger car and light truck tires, showed applicable mechanical properties in the new rubber compounds, and the compounds containing Dev.R demonstrated better properties than those containing GRP. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 208–217, 2005

Improvement of mechanical properties of rubber compounds using waste rubber/virgin rubber

Ground rubber powder (GRP) and devulcanized rubber waste obtained using the process of continuous shear flow reaction were used as both fillers and a part of rubber in virgin natural rubber (NR). The cure characteristics, swelling behavior, cross-link density, mechanical properties, and morphology were studied in our laboratory. The GRP and devulcanized rubber, which were generated from passenger car and light truck tires, showed applicable mechanical properties in new rubber compounds, and the compounds that contained devulcanized rubber showed better properties than those with GRP. In particular, devulcanized rubber as a part of rubber obtained through a cross-link reaction exhibited excellent mechanical properties, with a strong potential for future applications. POLYM. ENG. SCI., 45:1239–1246, 2005. © 2005 Society of Plastics Engineers

Processing guayule for latex and bulk rubber

The production of latex or bulk rubber from guayule has been pursued at various times since guayule rubber ceased being an article of commerce more than 60 years ago. Hypo-allergenic guayule latex has been prepared in 25–50-kg laboratory batches. Dilute latex was first washed from ground shrub and then concentrated by a combination of multi-stage centrifugation and creaming steps. This material was used to fabricate prototype medical products. A total of 8.8 t of dry guayule rubber was produced by simultaneous extraction of rubber and resin with a mixed organic solvent, followed by fractionation of the polymer stream. This material was tested in aircraft and light truck tires. At present, those seeking to process guayule must be prepared to meet several challenges: increasing the bulk viscosity of the rubber polymer, reducing the level of entrained resin and assuring oxidative and thermal stability. From this standpoint, latex process development remains in its early stages, whereas processing guayule for bulk rubber has been more thoroughly and successfully evaluated.

TIRE MAKERS TURN TO POLYURETHANE

MINDFUL OF FIRESTONE'S recent tire problems, Goodyear and Michelin are working on new-generation polyurethane technology that may be the key to making tires less prone to tread separation and blowout. Goodyear has signed an agreement to jointly develop an all-polyurethane car tire with Amerityre, a six-year-old Boulder City Nev., company that now makes polyurethane bicycle tires but has produced demonstration car and light-truck tires. According to Richard A. Steinke, Amerityre's president and CEO, a mixture of polyol, methylene diphenyl isocyanate (MDI), and a proprietary package of four additional ingredients can be injected into a mold containing a tire bead and reinforcement fabric and then spun to ensure a perfectly round tire Unlike conventional tires made by bonding several layers, monolithic polyurethane tires not subject to belt separation could be made on automated equipment to allow more rapid tire production at costs comparable to tires made today, Steinke says. The tire has a number of skepti...

The investigation of a towed trailer test for passenger tire coast-by noise measurement

It is difficult to quantify the portion of coasting vehicle noise that is due to tire-pavement interaction alone. There are often contributions from aerodynamic noise of the vehicle, transmission whine, noise from suspension components, and other miscellaneous sources. The towed-trailer method used in the revised SAE J-57 standard has been shown to be an effective means of isolating tire-pavement noise for truck tires. This paper reports the results of a test program conducted by SAE Tire Noise Standards Committee to evaluate the feasibility of towed-trailer coast-by testing of passenger and light truck tires. The results of tests conducted in April 1996 at the Ohio Transportation Research Center are described and they indicate that accurate measurements are possible for towed-trailer testing of passenger tires. It is shown that a key aspect of performing such a test is reducing the noise of the tow vehicle and that sufficient reduction is possible even for quiet test tires. During the period of this work, the ISO/TC 31/WG 3 working group developed a draft trailer test method for evaluating tire noise. This test procedure was also evaluated. The results show the proposed test method to be highly accurate for tire noise evaluation.

Construction of Rubber‐Modified Asphalt Pavements

Public road agencies are currently evaluating hot mix applications of PlusRide™ and Arm‐R‐Shield™ modified asphalt pavements. The processes use reclaimed rubber from ground automotive and light truck tires to reduce reflective and thermal cracking, suppress traffic noise, increase resistance to studded tire wear, and reduce the environmental impact of tire disposal. The projects constructed to date have primarily been experimental because the capital cost for this surfacing alternative ranges from 1.5 to 2 or more times the cost of conventional asphaltic concrete. A literature review of the construction practices and a questionnaire survey of contractors are used to determine why the construction costs of the modified mixes have been so high. One of the factors is the increase in financial risk perceived by contractors who bid on these types of pavements. Another cost factor, especially with the PlusRide™ system, is the unusual aggregate gradation required by the process. Still another concern is the increased mixing temperatures and times required by both rubber‐modified products. For Arm‐R‐Shield™, the high cost of the mix primarily reflects the cost of the asphalt‐rubber binder supplied by the manufacturer. These costs could be reduced by development of specifications which limit the contractor's risk, such as the use of conventional aggregate gradings, requiring minimum increases in mixing temperature and time, and allowing competition between rubber‐modified asphalt suppliers.