<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>Solar-reflective asphalt thin layer with TiO₂ and glass beads: A sustainable solution for permafrost protection and pavement performance enhancement in cold-regions</title>
      <link>https://trid.trb.org/View/2662139</link>
      <description><![CDATA[In cold regions, intense solar radiation on asphalt pavements induces thermal degradation and permafrost thaw settlement, causing cracking and uneven subsidence that compromise pavement serviceability and lifespan. Conventional heat-reflective coatings can reduce heat absorption but suffer from poor skid and fracture resistance, as well as limited durability due to texture loss and interfacial delamination, which ultimately diminishes their long-term cooling performance. To address these limitations, a novel heat-reflective asphalt thin layer was proposed using a clear asphalt binder with TiO₂ and glass beads incorporated via aggregate replacement. An innovative high-precision xenon lamp irradiation chamber was employed to conduct indoor tests, evaluating both surface and in-depth cooling performance. Pavement performance, including high-temperature stability, low-temperature cracking resistance, water stability, and skid resistance, was comprehensively assessed. Results showed that: (1) the optimal composition of 4 % TiO2 and 1.5 % glass beads (T4G1.5) balanced cooling performance and cost, reducing surface temperatures by over 8 °C and bottom-layer temperatures by up to 5 °C; (2) T4G1.5 exhibited superior texture depth (1.1 mm) and British Pendulum Number (83) compared to conventional coatings; and (3) T4G1.5 achieved satisfactory high-temperature and water stability, along with enhanced −10 °C fracture properties relative to SBS-modified asphalt mixtures, increasing stress intensity factor by 66.7 %, fracture energy by 128.1 %, and cracking resistance index by 35.9 %. These findings demonstrate that the heat-reflective asphalt thin layer is a durable and practical solution for protecting permafrost while maintaining pavement performance in cold regions.]]></description>
      <pubDate>Fri, 01 May 2026 14:33:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2662139</guid>
    </item>
    <item>
      <title>Computational analysis of ice formation on asphalt pavement incorporating phase change material (PCM)</title>
      <link>https://trid.trb.org/View/2643502</link>
      <description><![CDATA[The ice on the road surface could significantly reduce the skid resistance and pose a threat to traffic safety. To alleviate these safety issues, asphalt pavement incorporating phase change material (PCM) was developed to provide a sustainable anti-icing effect. A computational model was developed with the finite difference method to simulate the ice formation process. N-tetradecane-polymethyl methacrylate microcapsule powder was used to prepare asphalt concrete and experiments were conducted to validate the model. Results indicate that the average absolute error between the simulated and measured values is 1.2℃, which is acceptable. Compared to traditional models, this model considers the phase change of both the PCM-incorporated asphalt concrete (PCM-AC) and water-ice film. The analysis results indicate that the optimal phase change temperature for anti-icing is approximately 2–5°C. PCM-AC with higher thermal conductivity is more recommended, but when the thermal conductivity is reduced by 0.14–0.69 W·m−¹·K−¹, the anti-icing effect is more likely to be cancelled out. It is worth noting that there is an optimal thickness for the PCM-AC layer. The computational analysis helps transportation agencies understand the mechanism of ice formation on the PCM-incorporated pavement and the potential application of PCM in anti-icing.]]></description>
      <pubDate>Sun, 22 Feb 2026 14:58:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/2643502</guid>
    </item>
    <item>
      <title>Field Friction Testing</title>
      <link>https://trid.trb.org/View/2672003</link>
      <description><![CDATA[The primary goal of this project is to perform comprehensive field friction testing on various Stone Matrix Asphalt (SMA) surfaces with polymer-modified asphalt binders (i.e, “H” and “V” binders) across the entire state. Conducting these tests in real-world conditions is crucial for identifying potential safety concerns related to skid resistance. Previous year friction testing conducted on certain SMA surfaces within the SE region using the “V” binder indicated that these surfaces exhibited notably lower skid resistance values compared to other SMA surfaces after few years of construction. Building on these findings, this project intends to carry out an additional round of field friction measurements targeting those same SMA surfaces in the SE region, while also expanding the scope of testing to include more SMA sections throughout the state. The data collected from this expanded field testing will be instrumental in determining whether the relatively low friction numbers are attributable to the specific type of binder used, the aggregate materials involved, or a combination of both factors. Furthermore, to gain a broader understanding of the current skid resistance condition of the state’s pavement infrastructure, several additional pavement sites will be evaluated as part of this study. This holistic approach aims to provide actionable insights that can guide improvements in pavement design and material selection to enhance overall road safety and durability.]]></description>
      <pubDate>Wed, 18 Feb 2026 14:27:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2672003</guid>
    </item>
    <item>
      <title>Skid resistance evaluation of thin overlay asphalt mixtures based on three-dimensional texture reconstruction</title>
      <link>https://trid.trb.org/View/2639969</link>
      <description><![CDATA[Thin overlays, widely applied in road engineering to improve pavement smoothness and extend service life, generally demonstrate an initial decline and rapid deterioration in skid resistance. In this study, an optimized gradation design was conducted by adding supplementary sieve sizes of 5.6 mm, 6.7 mm, and 8 mm to enhance the skid resistance of the thin overlay asphalt mixture. The variation patterns of texture parameters featuring skid resistance were analyzed by three-dimensional reconstruction technology. Additionally, the road performance of the mixture was investigated through rutting tests and low-temperature bending tests. The skid resistance and its deterioration patterns were explored with pendulum tests, sand patch methods, and three-dimensional reconstruction technology. The results suggest that the optimized gradation-10, obtained by adding supplementary sieve sizes, exhibited better high-temperature stability and low-temperature crack resistance compared to SMA-10. The optimized gradation-10 also revealed superior performance in skid resistance decay, with a BPN attenuation rate of 21.7 %, which was lower than that of SMA-10 (29.9 %). Texture parameters, such as Sq, Sa, Ssk, Sku, Sdq, Sdr, Vmp, Vmc, and fractal dimension, reflect that the surface of the optimized gradation-10 had more peaks and valleys, greater texture depth, and sharper surface textures compared to SMA-10. Furthermore, correlation analysis specifies that Sa, Sdr, and Sdq were the primary texture parameters for characterizing skid resistance. Finally, regression equations for texture parameters, including EMTD-Sdr, MPD-Sdr, and BPN-fractal dimension, were established.]]></description>
      <pubDate>Fri, 06 Feb 2026 13:54:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2639969</guid>
    </item>
    <item>
      <title>Analysis of Porous Asphalt Mixtures Regarding Their Mechanical and Surface Characteristics</title>
      <link>https://trid.trb.org/View/2561983</link>
      <description><![CDATA[Porous asphalt (PA) is a type of layer utilized in flexible pavements, facilitating rapid drainage of water from the road surface. Consequently, the use of porous asphalt has been demonstrated to enhance road safety by improving skid resistance in wet weather conditions, reducing the incidence of hydroplaning, and preventing the transfer of water between vehicles. Furthermore, it contributes to a reduction in noise pollution and hydroplaning. The objective of this study was to investigate the performance and surface properties of porous asphalt mixtures. To this end, polymer-modified bitumen (PMB) was produced by the addition of 7%, 7.5%, and 8% of an SBS polymer additive to pure bitumen with a penetration class of 50/70 and 70/100. Subsequently, porous asphalt specimens were prepared in accordance with the Marshall design method. The Marshall parameters of the specimens were determined, and the Cantabro test (Part Loss), indirect tensile strength (TSR) test, and macrotexture tests were also performed on these specimens. The results obtained from the porous asphalt specimens for different polymer additive ratios, bitumen class, and bitumen ratios were compared. Essentially, the paper suggests that a 7.5%–8.0% SBS additive would be appropriate to meet the criteria for porous asphalt design.]]></description>
      <pubDate>Tue, 27 Jan 2026 16:16:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2561983</guid>
    </item>
    <item>
      <title>Laboratory evaluation of traffic effects on asphalt concrete contaminated by accident spills using Hamburg Wheel Tracking Device</title>
      <link>https://trid.trb.org/View/2595367</link>
      <description><![CDATA[A vehicle crashing against a surface or object always produces solid or liquid debris. The presence of foreign substances or distress on the asphalt concrete (raveling, potholes, ruts, cracking) leads to a reduction in road skid resistance. Skid resistance is one of the main factors contributing to the safety of road users. Over the years, numerous studies have been conducted on the presence of hydrocarbon spills, especially diesel, on the road surface. However, little attention has been paid to other types of dangerous liquid that can be spilled after a road accident. Moreover, these studies have focused on the performance degradation after spills, without examining the passage of vehicles on contaminated road surfaces. The idea developed in the present research is to analyse the consequences of the passage of a tire on a contaminated pavement. The effect of four different types of hazardous spills was tested on a wearing layer bituminous mixture (diesel, petrol, engine oil, brake oil). To simulate vehicle traffic on the road surface, a Hamburg wheel tracking device with rubber wheels at room temperature was employed. Asphalt concrete performances were evaluated in terms of skid resistance and rutting. The simulation of a vehicle load due to traffic showed different behaviour for oil and hydrocarbon spills on road surface.]]></description>
      <pubDate>Wed, 22 Oct 2025 09:02:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/2595367</guid>
    </item>
    <item>
      <title>Assessing mechanical properties and structural contribution of thin asphalt mixtures containing polymer and epoxy modified asphalt binders</title>
      <link>https://trid.trb.org/View/2595325</link>
      <description><![CDATA[Thin asphalt mixtures (TAMs) are commonly used functional surface layers with a thickness of 1.5 in. or less for pavement preservation. Examples include Open-Graded Friction Course (OGFC) and coarse-graded (CG) asphalt mixtures. OGFC mixture has a porous aggregate structure to facilitate drainage, reduce splash and spray, and improve skid resistance and driving safety. CG mixture has a dense aggregate structure with larger aggregates and fewer fines used for performance restoration, rutting correction, aging deceleration, and prolonging service life. However, most state highway agencies do not assign structural contribution of these TAMs in the design stage. The objective of this study was to evaluate the physical and mechanical performance of various TAMs and quantify their structural contribution to the pavement structure. Three TAMs were used, namely, CG mixture containing PG 70–22 asphalt binder (CG-70), OGFC containing PG 76–22 asphalt binder (OGFC-76), and OGFC containing 50 % epoxy asphalt binder (OGFC-50EAB). A suit of physical and mechanical tests was conducted followed by structural response analysis. The results showed that all TAMs were rutting-, moisture-, and raveling-resistant as measured by Hamburg wheel track, tensile strength ratio, and Cantabro abrasion loss tests, respectively. The improved performance of OGFC-50EAB as compared to OGFC-76 can be attributed to the cross-linked network formed between the epoxy resin and curing agents in the EAB. Pavement stress analysis showed that incorporating 1.5 in. of TAMs is expected to improve rutting by 13.9–21.1 % and fatigue cracking by 9.0–17.2 %.]]></description>
      <pubDate>Wed, 22 Oct 2025 09:02:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/2595325</guid>
    </item>
    <item>
      <title>A study on the development of Microsurfacing surface performance under laboratory-scale traffic simulation</title>
      <link>https://trid.trb.org/View/2571395</link>
      <description><![CDATA[In the field of preventative maintenance techniques, microsurfacing has gained scientific and practical interest, especially because of its effectiveness in restoring several distresses on structurally sound pavements; moreover, it provides social, economic, and environmental benefits since it is cold-applied in thin layers (less material and energy consumption), and it is fast-setting, allowing a quick reopening to traffic. Microsurfacings are also widely recognised for providing a regular and even surface texture with high skid resistance. Besides, assessing how the pavement surface performance changes over time under traffic conditions becomes essential in road pavement management. In light of the above and within the RILEM TC 280-CBE research activities framework, the work focused on optimising different bituminous cold microsurfacing mixtures: ‘Basalt 0/6’, ‘Basalt 0/8’, and ‘Granite 0/8’. The optimised mixtures were fully characterised and subjected to a laboratory traffic simulator’s action to study the development of the surface performance in terms of texture and skid resistance. A procedure has been implemented to model the relationship between the surface performance and the loading cycles, identifying the most representative phases (polishing and equilibrium) of the surface characteristics evolution. Notably, pertaining to skid resistance, the ‘Granite 0/8’ mixture achieves the same percentage decrease (about 18%) in a shorter conditioning period compared to the basalt ones. Regarding texture, the ‘Basalt 0/8’ mixture rapidly reaches the equilibrium phase but exhibits a lower drop (24.0%) compared to ‘Basalt 0/6’ and ‘Granite 0/8’ (38.0% and 39.6%, respectively).]]></description>
      <pubDate>Tue, 02 Sep 2025 08:45:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2571395</guid>
    </item>
    <item>
      <title>Effects of hazardous spills by road accidents on pavement texture and its deterioration mechanism</title>
      <link>https://trid.trb.org/View/2571254</link>
      <description><![CDATA[Hazardous spills from road accidents affect road safety, reduce the skid resistance of pavement and have a long-term impact on pavement texture. This paper conducted experimental investigation and molecular dynamics simulations on common road accident hazardous spills (petrol, diesel, engine oil, and brake fluid). A low-cost close-range photogrammetry technique was used to measure changes in pavement texture. The texture wear process of the contaminated pavement was simulated by using the Hamburg Wheel Tracking Device. Material Studio was used to simulate the interaction between hazardous spills and the bituminous conglomerate. Results showed an average reduction of 47 % in terms of skid resistance after contamination, with an absolute maximum decrease of 71 % observed with engine oil spillage. While cleaning can partially restore skid resistance, effects of contamination vary by spill type. Petrol and diesel dissolve bitumen, weakening the pavement structure, whereas engine oil remains on the surface, posing prolonged safety risks. Brake fluid infiltrates aggregates, potentially affecting their mechanical properties. The correlation between texture parameters and skid resistance is weak on newly paved roads but become more pronounced as wear progresses. Simulations reveal that hazardous spills adhere readily to bitumen and aggregates, exacerbating contamination effects. These findings provide scientific insights for optimizing spill response strategies and improving road safety management.]]></description>
      <pubDate>Fri, 29 Aug 2025 10:03:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/2571254</guid>
    </item>
    <item>
      <title>A Comprehensive Methodology for Predicting Field Skid Resistance of Bituminous Aggregates Based on Laboratory Test Data as Well as Their Past Skid Performance</title>
      <link>https://trid.trb.org/View/2567146</link>
      <description><![CDATA[A comprehensive laboratory and field test program was undertaken with the objective of developing an improved procedure for predicting field skid resistance performance of bituminous aggregates. The field test program included monitoring of 55 test pavement sections that were located in various climatic zones within the state of Texas over the 3-year study period. As a part of this monitoring program skid resistance of the pavement at 64 kmph and other lower speeds, British pendulum number, and pavement macrotexture were measured. The laboratory test program consisted of complete characterization of the pavement coarse aggregates using the following test methods: polish value test, Magnesium sulfate soundness test, LA abrasion test, acid insoluble residue test and petrographic analysis. The skid resistance data collected over the 3-year study period were then used to develop a "skid performance rating" for each pavement section. Subsequently, appropriate statistical analyses were conducted to develop regression models that relate skid performance rating to various laboratory test parameters. The findings revealed that much better correlations are obtained when aggregates are categorized into sub-groups that contain aggregate with similar mineralogical make up. Accordingly aggregates were categorized based on percent carbonate minerals and the acid insoluble residue. Statistical regression models were then developed for each aggregate category. A methodology was also developed to predict skid performance rating of the aggregate based on past skid performance data. This approach utilizes skid resistance measurements on in-service pavement that have been constructed previously using the aggregate of interest. A windows based computer software named SKIDRATE was developed to implement the proposed methodology.]]></description>
      <pubDate>Mon, 11 Aug 2025 16:31:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2567146</guid>
    </item>
    <item>
      <title>Development of a Standard Practice for the Design of Durable Open-Graded Friction Course (OGFC) Mixtures with Epoxy Asphalt</title>
      <link>https://trid.trb.org/View/2563638</link>
      <description><![CDATA[Open-graded friction course (OGFC) is a thin asphalt mixture surface layer. It is gap-graded with a high percentage of coarse aggregates that are nearly uniform in size, resulting in a high percentage of interconnected air voids and asphalt binder, which provides improved skid resistance, visibility, and decreased pavement-tire noise. However, construction personnel at the Louisiana Department of Transportation and Development (DOTD) reported that conventional OGFC mixtures have durability issues and a shorter service life compared to thin asphalt mixture lifts. The objective of this study was to evaluate the durability and performance of OGFC mixtures containing various types of asphalt binders. Six types of asphalt binders were utilized: unmodified PG 67-22 asphalt binder; conventional styrene-butadiene-styrene (SBS)-modified PG 76-22M asphalt binder; high-SBS content PG 88-28 asphalt binder; diluted epoxy-modified asphalt (EA) binder prepared at two dosage rates (25% and 50% by weight of asphalt binder); and a hybrid PG 76-22G modified asphalt binder prepared with SBS and crumb rubber modifier (CRM). Chemical compatibility and microscopic analyses were first conducted on EA binders to assess the compatibility between multiple asphalt binder sources and the EA binder. The optimal aggregate structures were determined based on the minimum required air voids and voids in coarse aggregate. Rheological and chemical characterization was conducted on the selected asphalt binders. Further, a suite of physical and mechanical mixture tests was performed to assess the performance of OGFC mixtures, including: draindown for mixture; draindown during production, storage, and construction; permeability for water drainability; loaded wheel track (LWT) for rutting and moisture susceptibility; Cantabro abrasion loss for durability; and indirect tensile strength for moisture susceptibility. Results from SARA fractions and Fourier Transform Infrared Spectroscopy tests showed that EA binders had the highest aging resistance. OGFC mixtures with EA binders exhibited the lowest draindown values. Mixtures with 50%EA and PG 88-28 binders demonstrated the highest resistance to rutting and moisture damage, as measured by LWT test for unconditioned and conditioned samples, respectively. All mixtures studied were durable, as determined by Cantabro abrasion loss values of 20% and 30% on unaged and aged (5 and 15 days) samples, respectively. Mixtures with 25%EA and 50%EA binders exhibited the highest resistance to moisture damage, as indicated by their tensile strength ratio results. Cost-effectiveness ratio (CER) results showed that mixtures containing 25%EA and 50%EA binders have higher effectiveness compared to the conventional OGFC mixture with PG 76-22M when tested for 30 days aged moisture-conditioned Cantabro specimens.]]></description>
      <pubDate>Fri, 20 Jun 2025 17:03:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/2563638</guid>
    </item>
    <item>
      <title>Field implementation of a rational Otta seal mix design for enhanced performance on low-volume roads</title>
      <link>https://trid.trb.org/View/2543887</link>
      <description><![CDATA[Low-volume roads connecting rural communities and agricultural fields face unique challenges due to heavy traffic and constrained budgets for maintenance and rehabilitation. The Otta seal surfacing technique utilizing bituminous material and graded aggregates to create a durable road surface has emerged as a promising solution. This study explores a rational mix design, a modified McLeod method, for Otta seal application considering local material properties, and compares it with existing design guidelines. The study involves constructing test sections following a rational design technique and conventional Overby recommended guidelines. The performance of the test sections was assessed by testing skid resistance, surface roughness, dust generation, and structural stiffness over a two-year period. The test section constructed following the modified McLeod method outperformed sections built per traditional Overby guidelines in terms of cost-effectiveness and overall performance. Specifically, the test section that was constructed using the modified McLeod method exhibited the lowest roughness, dust, and loose aggregate from the surface. Results from life cycle cost analysis (LCCA) highlight the economic benefits of the rational mix design technique, demonstrating the economic advantages of the rational mix design, showcasing lower construction and maintenance costs. By adapting the modified McLeod method to suit the local aggregate materials, engineers can achieve more appropriate and accurate application rates for both aggregates and binders, thereby optimizing the performance of the overall mixture. The study contributes practical insights for optimizing Otta-seal surfacing, emphasizing the significance of using local material properties and rational mix design for enhancing the longevity and cost-effectiveness of low-volume roads in Iowa.]]></description>
      <pubDate>Wed, 21 May 2025 09:52:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/2543887</guid>
    </item>
    <item>
      <title>Optimizing Agro-based Natural Fiber Parameters to Address Binder Drainage in Open-Graded Asphalt Friction Course Mixes Employing Response Surface Methodology</title>
      <link>https://trid.trb.org/View/2506147</link>
      <description><![CDATA[Open-graded asphalt friction courses (OGAFCs) offer benefits in terms of the absence of rainwater film, high skid resistance, low tire-pavement interaction noise, and better visibility under wet weather. Among the critical problems of binder draindown, raveling, and clogging encountered with OGAFCs, binder draindown is the one that can be largely resolved by using fiber with appropriate length, dosage, and type. With the growing interest in sustainable materials in road construction, the application of agro waste–derived natural fibers in pavements forms an innovative domain of research. In this study, four agro waste–derived biofibers, including banana fiber, sisal fiber, sunnhemp fiber, and pineapple fiber, were investigated as stabilizing agents to address the binder draindown challenge within OGAFC mixes. A response surface methodology (RSM) was used to optimize the fiber parameters of four agro waste–derived fibers for their application in OGAFC mixtures fabricated with unmodified and polymer-modified binders. RSM-based models were developed using three distinct input parameters: fiber lengths ranging from 3 to 12 mm, fiber dosages ranging from 0.15 to 0.45 %, and binder dosages ranging from 5.5 to 6.5 %, as well as one output parameter, binder draindown. The RSM-based developed regression models were statistically significant, with average R2 and adjusted R2 values higher than 0.9830 and 0.9695, respectively. Furthermore, the desirability function used to optimize fiber parameters yielded a desirability value greater than 0.84 for each developed model, indicating an exceptional level of predictive precision. Finally, during the model validation phase, an average percentage error deviation of 5.61 % demonstrated the efficacy of the RSM approach for fiber parameter optimization. The RSM-based optimization for each model with both binders, followed by parameter validation, yielded optimal values of 0.45 %, 9 mm, and 5.5 % for fiber dosage, fiber length, and binder dosages, respectively.]]></description>
      <pubDate>Tue, 25 Mar 2025 16:57:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/2506147</guid>
    </item>
    <item>
      <title>Effects of aggregate shape on the macrotexture and performance of chip seal: a laboratory study</title>
      <link>https://trid.trb.org/View/2509318</link>
      <description><![CDATA[Chip seal is an efficient maintenance strategy for bituminous pavements, with aggregate shape significantly impacting its embedment and performance, but there is limited quantification of its effects. Using the Aggregate Image Measurement System II (AIMS-II) for shape classification, this study investigated the influence of aggregate shape on chip seal's macrotexture and performance through a series of tests, including 3D laser scanning test, aggregate coverage test, skid resistance test, and sweep test, employing response surface methodology (RSM) for quantification. Results indicated that an abundance of flat aggregates deteriorates surface quality by increasing roughness and altering texture spacing, recommending their proportion be kept under 10%. Conversely, elongated aggregates enhance performance by enriching texture depth and sharpening surface peaks. Spearman rank correlation analysis identified the arithmetic mean peak curvature (Spc) and the root mean square height (Sq) as reliable measures for evaluating skid resistance and aggregate retention of chip seals, respectively.]]></description>
      <pubDate>Thu, 27 Feb 2025 10:46:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/2509318</guid>
    </item>
    <item>
      <title>Effect of Nominal Maximum Aggregate Size and Bitumen Content on Frictional Properties of Different Bituminous Surface Courses</title>
      <link>https://trid.trb.org/View/2407314</link>
      <description><![CDATA[Skid resistance, a measure of the force produced when a vehicle tire is prevented from sliding along the road surface, is a salient functional requirement of a pavement surface. Skid resistance is influenced by several factors, such as road surface texture, aggregate characteristics, aggregate gradation, binder content, surface temperature, and environmental conditions (presence of water film). This study investigated the frictional characteristics of three different asphalt surface courses, which included bituminous concrete (BC), open-graded friction course (OGFC), and stone matrix asphalt (SMA). The different factors considered during skid resistance measurement are: dry and wet surface conditions, varying nominal maximum aggregate size (NMAS—BC: 19.0 mm and 13.2 mm; OGFC: 19.0 mm and 12.5 mm; SMA: 13.2 mm and 9.5 mm), and variable binder content/percentage (for BC—5.5, 6.0, and 6.5%; for OGFC: 6.0, 6.5, and 7.0%; for SMA: 6.0, 6.5, and 7.0%). The British pendulum and sand patch test methods were used to evaluate the frictional/skid resistance and surface texture properties of these mixtures, respectively. OGFC mixtures showed better frictional characteristics compared to BC and SMA mixes. Texture depth played an important role in the development of friction, especially during the presence of water over the mix surface. Furthermore, the presence of a water film had a detrimental impact on frictional efficiency, i.e., higher water depth resulted in lower frictional resistance. Surface texture for different types of asphalt mixes (BC, SMA, and OGFC) had a fairly good correlation with skid resistance under both dry and wet conditions.]]></description>
      <pubDate>Wed, 11 Dec 2024 17:01:38 GMT</pubDate>
      <guid>https://trid.trb.org/View/2407314</guid>
    </item>
  </channel>
</rss>