<rss version="2.0" xmlns:atom="https://www.w3.org/2005/Atom">
  <channel>
    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
    <description></description>
    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
    </image>
    <item>
      <title>Laboratory study on the fracture resistance, moisture susceptibility, and marshall stability of hot mix asphalt mixtures containing parafiber, micro-silica, and hydrated lime</title>
      <link>https://trid.trb.org/View/2600855</link>
      <description><![CDATA[The growing volume of traffic in recent years has increased stress levels on pavements, leading to various forms of distress and higher maintenance costs. This problem is especially severe in cold regions, where harsh weather accelerates deterioration. As a result, identifying effective strategies to mitigate pavement damage is becoming increasingly essential. This research aims to investigate the simultaneous effects of Parafiber (PF), Micro-silica (MS), and Hydrated Lime (HL) on the behavior of Hot Mix Asphalt (HMA) and to identify the optimal combination of these additives to achieve the best performance. To reach this objective, the optimal ratio of each additive was first determined using Marshall stability testing based on peak stability. Then, the control and modified HMA samples underwent Marshall stability, Indirect Tensile Strength (ITS), and Semi-Circular Bend (SCB) testing to evaluate their stability, moisture susceptibility, and low-temperature cracking resistance, respectively. Moreover, the volumetric and mechanical properties of the HMA samples were assessed. According to the results, modifying HMA samples increased Marshall stability, density, voids filled with asphalt, moisture resistance, and fracture toughness, while decreasing flow value, voids in mineral aggregates, air voids, and extension at failure point compared to the control sample. Additionally, the 1.5 % PF-modified sample, followed by the sample containing the combination of all additives, exhibited the highest resistance to moisture effects, cracking at low temperatures, and plastic flow among all tested samples. This research helps engineers improve the characteristics of asphalt mixtures in various aspects and reduce the likelihood of cracking and other pavement distresses.]]></description>
      <pubDate>Thu, 30 Oct 2025 08:49:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/2600855</guid>
    </item>
    <item>
      <title>Effect of long-term aging on the fatigue properties of aramid fibres reinforced asphalt mixture</title>
      <link>https://trid.trb.org/View/2310640</link>
      <description><![CDATA[Synthetic fibres have been reported to provide substantial improvements to the mechanical properties of asphalt mixture. This study investigates the impact of aging on the cracking of aramid fibre-reinforced asphalt mixes (AFM) using the simplified viscoelastic continuum damage (S-VECD) theory. Loose asphalt mixtures with 0.05% fibre and control loose asphalt mixes were placed in an oven for 0, 1, 2, 4, and 7 days, respectively. Then, the viscoelastic properties and cracking behaviour of hot mix asphalt (HMA) and AFM were evaluated and compared using the dynamic modulus test and fatigue tests. The test results showed that the difference in the AMR (aging modulus ratio) values increased as the decrease in frequencies and temperatures increased. The aging sensitivity of the AFM was lower than the HMA after the 7d aging condition. The AMR is negatively correlated with the Sapp value which indicates fatigue cracking deterioration and modulus damage are correlated negatively during aging durations. The reductions in fatigue cracking performance of the AFM were 5%, 8%, 20%, and 23% subjected to 1d, 2d, 4d, and 7d aging conditions, which demonstrates the 4d aging condition is the key cracking stage during the aging durations. This study provides a reference for evaluating the anti-cracking performance of AFM under different aging conditions, which can be beneficial to aramid fibre asphalt pavement design and maintenance.]]></description>
      <pubDate>Mon, 05 Feb 2024 16:03:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/2310640</guid>
    </item>
    <item>
      <title>Laboratory Investigation of Draindown Behavior of Open-Graded Friction-Course Mixtures Containing Banana and Sugarcane Bagasse Natural Fibers</title>
      <link>https://trid.trb.org/View/2173740</link>
      <description><![CDATA[Open-graded friction courses (OGFCs) are asphalt paving mixes with a higher number of interconnecting air voids to provide advantages with respect to improved drainage, increased dry/wet surface friction resistance, decreased splash and spray, and reduced aquaplaning. However, binder draindown has been a recurring issue during the manufacture, storage, transportation, and service life of OGFC mixtures. The addition of stabilizers in the form of fiber is often used with OGFC mixes to counteract the draindown. Increasing environmental awareness, the depletion of fossil resources, and the rise of global waste problems have necessitated the use of locally accessible natural fibers as an alternative to expensive synthetic fibers. In this study, the banana fiber obtained from the waste pseudo-stem of the banana plant post-harvesting and the sugarcane bagasse fiber obtained from the post-residual after sugar extraction is explored along with a commercial cellulose fiber to evaluate the draindown characteristics of OGFC mixtures. A cone penetration test and fiber absorption test was performed on the fiber-mixed asphalt binder. The draindown characteristics of 168 combinations of OGFC mixes were evaluated considering various parameters, viz. fiber parameters (types, lengths, dosages), binder dosage, binder types (unmodified binder and polymer-modified binder), and time period. Finally, a statistical analysis was conducted to determine the efficacy of different influencing factors. The best performance was exhibited by banana fiber, which had a dosage of 0.45% and a length of 9?mm, followed by sugarcane bagasse and cellulose fiber. All the input factors were found to be statistically significant.]]></description>
      <pubDate>Mon, 22 May 2023 08:55:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2173740</guid>
    </item>
    <item>
      <title>Evaluation of engineering properties of Fiber-reinforced Usual-temperature Synthetic Pitch (USP) modified cold mix patching asphalt</title>
      <link>https://trid.trb.org/View/1926810</link>
      <description><![CDATA[As a common-used pothole repairing material, cold mix patching asphalt (CMA) has been widely used in practice. This article aims to develop a novel CMA with good overall performance and better environmental-friendliness. A few environmental-friendly ingredients, including a modifier named Usual-temperature Synthetic Pitch (USP), polyester-basalt composite fibers, a commercial anti-stripping agent, a commercial tackifier and biodiesel, were utilized for preparing Fiber-reinforced USP modified CMAs (FUAs). Laboratory tests, including workability assessment tests, Marshall stability tests, boiling water tests, rolling sieve cohesion tests, freeze-thaw splitting tests, wheel tracking tests and three-point bending tests, etc. were conducted to evaluate the workability, Marshall stability, adhesion, moisture susceptibility, rutting resistance, bending resistance and storage stability. Two mix designs of the cutback (termed as Scheme 1 and 2) with weight ratios of 100:6:18:0.3:0.6 and 100:6:20:0.4:0.8 for binder: USP: biodiesel: anti-stripping agent: tackifier were considered. Effect of fiber content (0.2%, 0.3%, 0.4% and 0.5% by aggregate weight) was also investigated considering an optimal polyester to basalt fiber weight ratio of 3:2. The results show that the optimal fiber content is 0.4%. The engineering properties of FUAs meet the construction requirements, and they also present good storage stability. Scheme 2-based cutback shows better workability, smaller penetration and better binder-aggregate adhesion than the Scheme 1-based cutback; consequently, the Scheme 2-based FUA presents advantages over Marshall stability, rutting resistance and bending resistance. Compared with Styrene-Butadiene-Styrene (SBS) modified CMAs, FUAs possess better overall performance and advantages over environmental conservation. The FUAs, therefore, have good application prospects in pavement repair.]]></description>
      <pubDate>Wed, 25 May 2022 09:40:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/1926810</guid>
    </item>
    <item>
      <title>Mechanical characterization of warm mix asphalt mixtures made with RAP and Para-fiber additive</title>
      <link>https://trid.trb.org/View/1767518</link>
      <description><![CDATA[Asphalt recycling can help reserve natural resources and save money. However, in producing hot mix asphalt (HMA), utilizing reclaimed asphalt pavement (RAP) high heat rate is produced which leads to the stiffening of asphalt binder and producing toxic gases. This in turn will cause massive environmental pollution. As a money-saving technology, Warm Mix Asphalt (WMA) produces asphalt mixture at lower temperatures, and reduces environmental pollution as well as ageing and stiffness of the asphalt binder. This study is aimed at investigating the use of two techniques to decrease environmental pollution, save energy and costs, and improve asphalt mixture performance: WMA technique and RAP materials in asphalt mixtures. The Para-fiber additive was also employed in different values. With respect to the RAP, the use of virgin aggregates was decreased. To compare and evaluate the mechanical performance of asphalt mixtures, tests including resilient modulus, dynamic creep, indirect tensile strength, indirect tensile fatigue, and boiling water tests were conducted. According to the results, using RAP led to an increase in resilient modulus of mixtures and improved the resistance against permanent deformation. Also, by the addition of Para-fiber, the fatigue life of asphalt was improved. Moreover, according to the results of the fatigue test, it was shown that by the addition of RAP, the fatigue life of mixtures was decreased remarkably, yet it was enhanced by using Para-fiber.]]></description>
      <pubDate>Mon, 22 Mar 2021 10:34:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/1767518</guid>
    </item>
    <item>
      <title>Effect of Ceramic Fibers on the Thermal Cracking of Hot-Mix Asphalt</title>
      <link>https://trid.trb.org/View/1730438</link>
      <description><![CDATA[Thermal or low-temperature cracking is caused by extremely cold weather or temperature cycles in cold climates. This distress can be controlled by, among others, bitumen modification. In light of the positive performance of natural and synthetic fibers in previous studies, this study investigated the effect of ceramic fiber, a low-cost and available mineral fiber, as a bitumen modifier on the low-temperature cracking potential of asphalt mixtures. Bending beam rheometer (BBR) and semicircular bending (SCB) tests were performed to evaluate the rheological properties of bitumen and low-temperature performance of asphalt mixture, respectively. In addition, direct tensile strength tests using the pull-off method for cohesive failure and adhesive failure conditions, as well as thermodynamic theory based on the surface free energy (SFE) method were used to determine the mechanism of impact of ceramic fibers on bitumen and asphalt mixture properties at low temperature. The results indicated that the application of ceramic fibers up to 0.4% by weight of bitumen reduced creep stiffness and increased m-value, thereby making the rheological properties of bitumen suitable for one grade lower than the control bitumen. The results of the SFE method demonstrated that the application of ceramic fibers increased the acidic component and decreased the total SFE of the control bitumen, thus increasing the free energy of adhesion in samples with both acidic and basic aggregates. Also, bitumen modification increased the nonpolar SFE, and consequently increased the total SFE, thereby improving bitumen resistance to cohesive failure. The results of the pull-off test at the thick and thin bitumen film conditions indicated that the application of ceramic fiber enhanced the resistance to cohesive and adhesive failure. Statistical analysis also revealed that thermodynamic variables played an effective role in the type of failure. Based on the results of the SCB test parameters, the use of ceramic fiber, especially up to 0.4% by weight of bitumen, improved all three parameters of load peak, fracture energy, and fracture toughness, thus decreasing the potential of low-temperature cracking in samples made with the modified bitumen. Also, based on the statistical analysis, the performance parameters of the asphalt mixture against low-temperature cracking were efficiently dependent on the thermodynamic variables obtained from the SFE components of bitumen and aggregate.]]></description>
      <pubDate>Thu, 17 Sep 2020 17:53:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/1730438</guid>
    </item>
    <item>
      <title>Incorporation of synthetic macrofibres in Warm Mix Asphalt</title>
      <link>https://trid.trb.org/View/1679789</link>
      <description><![CDATA[The reinforcement of asphalt concrete with fibres is not a common practice in the pavement field. Although some research papers refer to the use of microfibres, the behaviour of asphalt concrete incorporating macrofibres has not been studied. Warm Mix Asphalt (WMA) is environmentally friendly because it is possible to reduce emissions and fuel consumption. WMA technologies allow the reduction of mixing temperatures. The WMAs performances must be better than or similar to traditional Hot Mix Asphalts (HMAs). This work explores the benefits of incorporating synthetic macrofibres in WMA. Important improvements in rutting performance were observed when comparing to WMA without fibres, outperforming even HMA. Improvements in fracture behaviour at low to medium temperatures represent another benefit of macrofibre incorporation, confirming the advantages of the synergic combination of WMA and synthetic macrofibres.]]></description>
      <pubDate>Fri, 20 Mar 2020 10:11:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/1679789</guid>
    </item>
    <item>
      <title>Performance of hot bituminous mixes admixed with blended synthetic fibers</title>
      <link>https://trid.trb.org/View/1648617</link>
      <description><![CDATA[With increased traffic loads and climate changes, even well designed bituminous surfaced roads are fast deteriorating. Hence, in recent years, research has been focusing on the control of fracture and permanent deformations in flexible pavements. In order to address issues of rutting, fatigue, and low-temperature cracking, different types of polymer modifiers have been utilized. The use of blended synthetic fibers as a low cost modifier in bituminous pavement mix was found to be effective in improving performance compared to other modifiers, as an attractive option. In this study, a mixture of polypropylene and aramid fibers was introduced to evaluate the performance characteristics of a bituminous mixture. The objective of the study was to evaluate the mechanistic properties of conventional and fiber-reinforced bituminous mixtures and implications of fiber addition on thickness and cost reduction of bituminous layers. Effect of addition of fiber on pavement design has also been studied. The laboratory experimental program included indirect tensile strength tests, wet indirect tensile strength after water and MIST (Moisture Induced Sensitivity Test) conditioned, dynamic creep and resilient modulus at different temperatures. This paper reports on the reduction of thickness of pavement also cost analysis with the addition of fibers and resulting properties. Optimum fiber dosage was determined to be 0.05% by weight of mix based on laboratory performance of mix. The results show that fiber improved the mixture performance by a drop of rut depth up to 50% and adding fatigue resistance up to 400%. Moisture resistance and indirect tensile strength of fiber mixture is increased by 9 to 14% in comparison to conventional mix. While the addition of fibers resulted in 2% higher cost, manifold increase of performance and 13% reduction in pavement thickness would justify the act.]]></description>
      <pubDate>Mon, 09 Sep 2019 15:06:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/1648617</guid>
    </item>
    <item>
      <title>Reuse of Carbon Fiber Composite Materials in Porous Hot Mix Asphalt to Enhance Strength and Durability</title>
      <link>https://trid.trb.org/View/1630579</link>
      <description><![CDATA[Porous hot mix asphalt (PHMA) allows runoff to infiltrate through the pavement. Cured carbon fiber composite materials (CCFCM)s from aerospace production lines were ground into three size groups (Fine, Medium, and Large) and reused as reinforcement agents for PHMA in comparison to commercial synthetic fiber. The Fine CCFCMs premixed with liquid asphalt binder performed the best to reinforce PHMA in terms of indirect tensile strength and cracking resistance at both 25 °C and −10 °C. The addition of fine CCFCMs and synthetic fibers reduced the porosity by 17% and infiltration rate by up to 20%, while both fibers showed to prevent draindown of asphalt binder at an elevated temperature. The PHMA reinforced with the Fine CCFCMs performed the best in rutting resistance.]]></description>
      <pubDate>Tue, 27 Aug 2019 09:21:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/1630579</guid>
    </item>
    <item>
      <title>Field Implementation and Monitoring of Behavior of Economical and Crack-Free High-Performance Concrete for Pavement and Transportation Infrastructure Constructions – Phase II</title>
      <link>https://trid.trb.org/View/1595698</link>
      <description><![CDATA[Economical and crack-free high-performance concrete (Eco-HPC) is a new class of environmentally friendly and cost-effective high-performance concrete (HPC) that is made of low binder content, high volume of supplementary cementitious materials (SCMs), and shrinkage mitigating materials. The initial phase of research that involved an extensive laboratory investigation indicated that the designed Eco-HPC can secure high resistance to shrinkage cracking, and high strength and durability. The aim of this project was to validate findings of the previous research via field implementation and develop guidelines for the use of EcoHPC for sustainable transportation infrastructure construction. Two classes of Eco-HPCs were developed for field demonstrations: Eco-Pave-Crete made for pavement construction and Eco-Bridge-Crete for bridge construction. Fresh, mechanical properties, and shrinkage of these Eco-HPC mixtures were validated through laboratory and prototype-scale testing and compared to those obtained using a MoDOT reference mixture. The Eco-Pave-Crete, Eco-Bridge-Crete, and MoDOT reference mixture were proportioned with binder contents of 320 kg/m3 (540 lb/yd3), 350 kg/m3 (590 lb/yd3), and 375 kg/m3 (632 lb/yd3) cementitious materials, respectively. Test results indicate that it is possible to design Eco-HPC with low drying shrinkage (＜ 300 μstrain after 250 days) and no restrained shrinkage cracking up to 55 days. Prototype-scale slabs cast with Eco-Bridge-Crete exhibited lower shrinkage compared to the reference concrete. Further prototype-scale reinforced concrete beams made with Eco-Bridge-Crete containing more than 50% replacement of cement to SCMs and either 0.35% structural synthetic fibers or recycled steel fibers developed significantly higher flexural strength and toughness. A comprehensive probabilistic life-cycle cost analysis methodology was carried out to quantify the life cycle costs of Eco-HPC and conventional materials that link laboratory-measured parameters to actual field performance. Compared to the MoDOT reference mixture, the optimized Eco-HPC mixtures developed for pavement and bridge applications exhibited approximately 40% lower embodied energy and 55% lower global warming potentials. The use of the proposed Eco-HPC mixtures could lead to reductions of about 4.7% of agency costs and 17.3% of the total life-cycle cost for bridge deck construction and 3.2% of agency cost and 6.2% of the total life-cycle cost for pavement construction in high traffic conditions.]]></description>
      <pubDate>Wed, 24 Apr 2019 09:33:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/1595698</guid>
    </item>
    <item>
      <title>Experimental Evaluation of the Interaction between Geosynthetic Reinforcements and Hot Mix Asphalt</title>
      <link>https://trid.trb.org/View/1558695</link>
      <description><![CDATA[The advent of interlayer reinforcements with a wide range of stiffness properties has provided the opportunity to produce a specially-designed composite material that can enhance pavement performance in various aspects (e.g., rutting, fatigue cracking, reflective cracking). However, reinforcements may negatively affect the bonding between asphalt layers. The objective of this paper is to evaluate experimentally the interlayer de-bonding effect. In particular, reinforced and unreinforced asphalt specimens were tested in a direct shear test setup and their interlayer bond strength was characterized. The reinforcement inclusions used in the testing program involved synthetic materials made from various polymers, including polyester, polyvinyl alcohol, and glass fiber. Results of the experimental program indicated that the de-bonding effect impacts not only the maximum bond strength, but also the stiffness and the average interlayer shear strain at the maximum bond strength. Moreover, coverage ratio and the thickness of the reinforcement yarns were identified as additional important parameters in characterization of the interlayer de-bonding effect.]]></description>
      <pubDate>Sun, 16 Dec 2018 21:39:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/1558695</guid>
    </item>
    <item>
      <title>Improving the Mechanical Properties of Cold Mix Asphalt Mixtures Reinforced by Natural and Synthetic Fibers</title>
      <link>https://trid.trb.org/View/1558706</link>
      <description><![CDATA[The enhancement of the performance of flexible pavements by reinforcing asphalt mixtures is considered valuable because of the negative environmental conditions and heavy loads pavements endure resulting in the unsatisfactory performance of conventional mixtures. This research investigates the mechanical properties of cold mix asphalt (CMA) mixtures reinforced by natural (coir) and synthetic (glass) fibers, the main aim being to develop and optimise a high performing CMA mixture for use as a surface course, incorporating natural and synthetic fibers, which could be used in place of hot mix asphalt (HMA) in any situation. Laboratory investigations were performed to measure and evaluate the mechanical properties of reinforced and unreinforced mixtures with different fiber types, contents and lengths. These investigations included the indirect tensile stiffness modulus test, uniaxial creep test, wheel tracking tests and water sensitivity in terms of indirect tensile strength. The results revealed a considerable improvement in the mechanical properties of CMA specifically because of the high stiffness and tensile strength properties of the fibers used. Due to these improvements, rutting resistance and structural resistance to distress occurring in asphalt pavements and pavements service life, may be enhanced.]]></description>
      <pubDate>Tue, 04 Dec 2018 11:38:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/1558706</guid>
    </item>
    <item>
      <title>A Laboratory Study of High-Performance Cold Mix Asphalt Mixtures Reinforced with Natural and Synthetic Fibres</title>
      <link>https://trid.trb.org/View/1510957</link>
      <description><![CDATA[This research aims to examine the impact of using natural and synthetic fibres as reinforcing materials, on the mechanical properties and water susceptibility of cold mix asphalt (CMA) including indirect tensile stiffness and resistance to rutting, cracking and moisture damage. Four different types of fibres were used: glass as a synthetic fibre, and hemp, jute and coir as natural fibres. Various samples of CMA, with and without fibres, were fabricated and tested. Traditional hot mix asphalt (HMA) was also used for comparison. The results indicate a significant improvement in the indirect tensile stiffness modulus, for all fibre-reinforced CMA mixtures, over different curing times. The improved tensile behaviour represents a substantial contribution towards slowing crack propagation in bituminous mixtures, while scanning electron microscopy analysis confirmed the fibre shape and surface roughness characteristics. The improved performance of the reinforced mixtures with both natural and synthetic fibres, facilitated a substantially lower permanent deformation than traditional hot and cold mixtures at two different temperatures (45 °C and 60 °C). When using glass and hemp fibres as reinforcing materials, there was a significant improvement in CMA in terms of water sensitivity. Resistance to surface cracking was also improved when fibres were incorporated. Based on the test results, 0.35% fibre content by mass of dry aggregate and 14?mm fibre length are recommended to achieve the optimum performance output for indirect tensile stiffness.]]></description>
      <pubDate>Fri, 22 Jun 2018 16:40:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/1510957</guid>
    </item>
    <item>
      <title>Effects of Confinement on the Dynamic Modulus of Hot Asphalt Mixtures and Interaction with Binder/Fiber Combinations and Air Voids</title>
      <link>https://trid.trb.org/View/1392956</link>
      <description><![CDATA[Dynamic modulus (|E*|) is used to evaluate the response of asphalt concrete in mechanistic-empirical pavement design. Test values measured at different temperature/frequency combinations are used to create a mastercurve, which allows interpolating |E*| for any other condition. Tests are usually performed unconfined even though confined conditions may be more representative of field conditions. This paper describes test results for 4 mixes with a dense gradation used at the Honolulu International Airport. The different mixes were obtained by using two different asphalt binders, a PG64-22 and a polymer modified PG76-22, with and without the addition of a synthetic fibers for each binder. The synthetic fibers used consist of a mix of polyolefin and aramid fibers. The objective is to study the effects on the mastercurve of these different mixtures at different confinement levels (0, 69, 138, and 207 kPa) and different air voids levels (4%, 7%, and 9%). The benefits of confinement varied with the combination of binder type and air voids. For modified mixtures, |E*| was observed to increase significantly with confinement (normally at a decreasing rate) at high temperatures and low frequencies. These benefits are observed for all air voids. For unmodified mixtures, confinement increases substantially at lower and intermediate air voids but the benefits practically disappear at higher air voids. At low temperatures/high frequencies, the confinement effects are minimal. At high temperature/low frequencies, the modified binder increases the confined |E*| significantly but the fibers tend to reduce it slightly with respect to the control mix]]></description>
      <pubDate>Wed, 20 Jan 2016 12:41:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/1392956</guid>
    </item>
    <item>
      <title>Alternative Pavements for Snowmobile Crossings</title>
      <link>https://trid.trb.org/View/918733</link>
      <description><![CDATA[Excessive highway pavement wear from snowmobile traffic is a maintenance problem for the New Hampshire Department of Transportation. The snowmobiles and trail grooming equipment scar and erode the pavement surfaces, eventually creating wide ruts across the State’s highways that cause potential safety issues for vehicular traffic. The damage includes breaking off bits of the pavement’s edge until the travel lanes are threatened. The Department performed an evaluation of alternative pavement treatments intended to protect the pavement surface from excessive degradation. Cleanosol is a surface-applied thermoplastic material that has been successfully used to armor snowmobile crossings in Michigan and Wisconsin. Imprint® is a synthetic surface material developed in the United Kingdom that consists of a hot applied resin-based compound with graded sand and granite aggregate, reinforced with two types of fibers. Three pairs of snowmobile crossings, known for heavy snowmobile traffic and excessive pavement wear, were treated with each product. Wear was measured and patterns were observed over three winters. Unit wear rates of the test materials did not indicate a greater durability than conventional hot mix asphalt (HMA). Cleanosol was the easiest and quickest product to install, and was the least expensive as compared with Imprint and HMA repair. The convenience and lower cost of installing Cleanosol make it a good choice for the repair of snowmobile trail damage across the State’s highways. Recommendations include: (1) Adoption of a revised Motorized Recreational Vehicle Trail Crossing detail for use in permitting new trail crossings; (2) Improvement of existing trail crossings to bring them into reasonable compliance with the Motorized Recreational Vehicle Trail Crossing detail; and (3) A statewide program for treating, improving and maintaining snowmobile crossings in collaboration with the recreational vehicle community.]]></description>
      <pubDate>Wed, 02 Jun 2010 16:33:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/918733</guid>
    </item>
  </channel>
</rss>