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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=PHNlYXJjaD48cGFyYW1zPjxwYXJhbSBuYW1lPSJkYXRlaW4iIHZhbHVlPSJhbGwiIC8+PHBhcmFtIG5hbWU9InN1YmplY3Rsb2dpYyIgdmFsdWU9Im9yIiAvPjxwYXJhbSBuYW1lPSJ0ZXJtc2xvZ2ljIiB2YWx1ZT0ib3IiIC8+PHBhcmFtIG5hbWU9ImxvY2F0aW9uIiB2YWx1ZT0iMCIgLz48L3BhcmFtcz48ZmlsdGVycz48ZmlsdGVyIGZpZWxkPSJpbmRleHRlcm1zIiB2YWx1ZT0iJnF1b3Q7TWVtYnJhbmVzJnF1b3Q7IiBvcmlnaW5hbF92YWx1ZT0iJnF1b3Q7TWVtYnJhbmVzJnF1b3Q7IiAvPjwvZmlsdGVycz48cmFuZ2VzIC8+PHNvcnRzPjxzb3J0IGZpZWxkPSJwdWJsaXNoZWQiIG9yZGVyPSJkZXNjIiAvPjwvc29ydHM+PHBlcnNpc3RzPjxwZXJzaXN0IG5hbWU9InJhbmdldHlwZSIgdmFsdWU9InB1Ymxpc2hlZGRhdGUiIC8+PC9wZXJzaXN0cz48L3NlYXJjaD4=" rel="self" type="application/rss+xml" />
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    <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>
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    <item>
      <title>A nonlinear methodology for the sloshing assessment in the membrane-type LNG cargo containment system</title>
      <link>https://trid.trb.org/View/2653035</link>
      <description><![CDATA[With tightening environmental regulations, demand for eco-friendly fuels has been increasing, driving a steady rise in orders for LNG-fueled ships and LNG carriers. In particular, the demand for membrane-type LNG carriers, which offer excellent safety and economic efficiency, has been growing significantly. However, sloshing during operation significantly impacts the structural integrity of cargo tanks, and high-amplitude sloshing loads can cause permanent damage. Traditional linear-based sloshing assessment methods provide conservative, relatively safe results but fail to capture the nonlinear characteristics of actual sloshing loads adequately. Although several classification societies have proposed assessment procedures that incorporate structural nonlinearity, further refinement is required for practical application. In this study, an improved sloshing assessment methodology that considers structural nonlinearity was proposed, based on Lloyd's Register (LR) procedures, and applied to the MARK III Flex cargo containment system (CCS) of a 174K LNG carrier. Model tests were conducted to define the expected ranges of peak pressure and rising time. In addition, numerical simulations incorporating strain-rate effects and the plastic deformation behavior of R-PUF (reinforced polyurethane foam) under sloshing loads were performed, and the predicted dynamic responses were validated against experimental results. Furthermore, empirical formulations of the dynamic response factor were derived for different failure modes of CCS components. Finally, the utilization factor of the MARK III Flex CCS was evaluated using sloshing loads obtained from the 174K LNG carrier model tests, thereby validating the practicality and reliability of the proposed methodology. The proposed method quantitatively accounts for the structural nonlinear response of the MARK III Flex CCS to sloshing loads while considering hull stiffness, thereby balancing prediction accuracy and engineering practicality for practical applications.]]></description>
      <pubDate>Mon, 06 Apr 2026 08:50:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2653035</guid>
    </item>
    <item>
      <title>Anti-aging and self-healing SBS-modified bitumen waterproofing membrane based on montmorillonite and dynamic acylhydrazone bonds</title>
      <link>https://trid.trb.org/View/2578623</link>
      <description><![CDATA[The development of styrene-butadiene-styrene (SBS) block copolymer modified bitumen (SMB) waterproofing membrane with excellent anti-aging and crack self-healing properties is important to solve the persistent problems of building leakage. In this study, vinyltriethoxysilane modified montmorillonite (VTES-MMT) and acylhydrazone compound (AC) were synthesized and used to prepare a novel anti-aging and self-healing SMB. The structures of VTES-MMT and AC were characterized, and the effects of VTES-MMT and AC on the microstructure, physical properties, mechanical properties, self-healing properties and aging properties of SMB were systematically investigated. The results show that vinyl-functionalized VTES-MMT and AC with vinyl ends were successfully synthesized and they have good thermal stability. VTES-MMT and dynamic acylhydrazone bonds were introduced into SMB through the cross-linking reaction between vinyl and SBS. VTES-MMT and AC improved the dispersion stability, physical and mechanical properties of SMB and endowed it with excellent crack self-healing properties. Compared with SMB, the healing index (HI) and the impermeable pressure of VTES-MMT/AC/SMB increased by 52.86 % and 0.41 MPa. The introduction of VTES-MMT and dynamic acylhydrazone bonds effectively mitigated the oxidative condensation of bitumen and the chain-breaking degradation of SBS during the aging process. Compared with SMB, the low temperature flexibility increment, elongation at break retention rate and peel strength retention rate of VTES-MMT/AC/SMB were reduced by 6℃, 18.66 % and 21.76 % after UV aging, respectively. The cracks of VTES-MMT/AC/SMB could still be healed completely after aging, and its HI and impermeability pressure decreased by only 14.38 % and 0.08 MPa after UV aging, which implied that the synergistic effect of VTES-MMT and AC significantly improved the aging resistance of SMB, and VTES-MMT/AC/SMB still maintained a good crack self-healing ability after aging.]]></description>
      <pubDate>Mon, 08 Sep 2025 14:54:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2578623</guid>
    </item>
    <item>
      <title>Aging behavior and life prediction of sustainable self-healing SBS modified bitumen waterproof membrane with dynamic acylhydrazone bonds</title>
      <link>https://trid.trb.org/View/2566609</link>
      <description><![CDATA[The introduction of dynamic acylhydrazone bonds in styrene-butadiene-styrene block copolymer (SBS) can endow SBS modified bitumen (SMB) waterproof membrane with good self-healing ability. In this paper, two kinds of self-healing SMB (SHMB-A and SHMB-B) waterproof membranes were prepared using aliphatic acylhydrazone compound (AC-A) and aromatic acylhydrazone compound (AC-B). The effects of aging on the microstructure, chemical structure, physical properties, mechanical properties and self-healing performances of SHMB waterproof membranes were investigated, and the service lives of SMB and SHMB waterproof membranes were predicted by the Arrhenius model. The results showed that compared with SMB, SBS in SHMB had fewer CC bonds, the microstructure of SHMB was more lightly damaged under the influence of UV light, heat, oxygen and water, and thus the deterioration degree of the physical-mechanical properties of SHMB were smaller than those of SMB after aging. The dynamic acylhydrazone bonds existed stably in SBS after aging and still provide a good crack self-healing ability for SHMB. For example, the elongation at break recovery rate and impermeable pressure of SMB were only 18.51 % and 0.12 MPa after thermal aging, respectively, while the elongation at break recovery rate and impermeable pressure of SHMB-A and SHMB-B reached 68.27 %, 73.36 % and 0.45 MPa, 0.47 MPa after thermal aging, respectively. According to the Arrhenius model, the predicted lifetimes of SMB, SHMB-A and SHMB-B waterproof membranes were 19.31 years, 29.99 years and 27.12 years, respectively, which indicated SHMB had better aging resistance.]]></description>
      <pubDate>Tue, 02 Sep 2025 08:45:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/2566609</guid>
    </item>
    <item>
      <title>A global approach to detecting and characterizing water leakage in a concrete bridge deck: Parametric study to validate an adapted Full-Waveform Inversion method</title>
      <link>https://trid.trb.org/View/2489983</link>
      <description><![CDATA[The objective of this study is to address issues related to defects in waterproofing membranes through the use of Ground Penetration Radar to detect water leakage into the concrete layer of bridge decks. Given that processing radar signals based solely on temporal data introduces significant estimation errors, an advanced method optimized from Full-Waveform Inversion (FWI) is employed. This method accounts for several unknown factors, including boundary conditions, antenna positioning inaccuracies, and approximations inherent in 2D modeling during the inversion process. The method is adaptable and capable of reconstructing both the dielectric and geometric parameters of a multilayered structure with any number of layers and unknown parameters using just a few A-scans (up to 10, depending on the number of parameters and layers). In contrast, other methods typically require several hundred A-scans. This efficiency is achieved due to the two-dimensional nature of the layer system. Additionally, the simplicity of the structure facilitates a much faster and more straightforward inversion algorithm, hence making these features especially advantageous for practical applications. The optimized Full-Waveform Inversion approach allows for an accurate determination of unknown parameters within a multilayered medium. The high accuracy of this method is validated through a direct comparison with experiments, wherein the exact parameters are known. Such an approach enables the attainment of a low relative error using the currently available measurement device.]]></description>
      <pubDate>Thu, 20 Feb 2025 16:25:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2489983</guid>
    </item>
    <item>
      <title>Ultra-thin sealing surface treatments for solar radiation screening on asphalt facing dams</title>
      <link>https://trid.trb.org/View/2465353</link>
      <description><![CDATA[Bituminous materials are widely used in a large range of hydraulic applications due their excellent waterproofing properties. More than 300 asphalt facing reservoirs were built in the last century, presenting higher mechanical and hydraulic performance when compared with other facing alternatives, such as cement concrete or steel membranes. On the other hand, the dark colour of bitumen may lead to high temperatures inside asphalt paved system, affecting long term ageing of binder and jeopardizing the quality of the impervious layer. Recently, multifunctional ultra-thin surface treatments are becoming an alternative to demolition-reconstruction of the impervious layer, significantly abating the quantity of energy and raw materials required for maintenance. High-reflective surface treatments may represent also an effective solution to reduce the temperature of asphalt layers, extending the service life of the dam embankment and reducing the need of maintenance. In fact, there is a lack of literature concerning the assessment of thermal impact on asphalt dams. In the light of above, a number of different combinations of sealing surface treatments were investigated in this study. An ad hoc testing equipment and procedure were designed to perform an artificial solar irradiance test. A complete colorimetry analysis was performed and the outcomes were compared with temperature data, making use of a thermal camera and of embedded sensors for surface and base temperature measurements, respectively. Major results and their relationships have been commented in-depth along with proposed further research activities.]]></description>
      <pubDate>Fri, 27 Dec 2024 15:27:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/2465353</guid>
    </item>
    <item>
      <title>Water Resistance and Pore Characteristics of Organic Silane Waterproof Membrane in Roadbed</title>
      <link>https://trid.trb.org/View/2409517</link>
      <description><![CDATA[In this paper, the inhibiting effect of organic silane waterproofing membrane on the capillary water rise height (CRH) of roadbed soil has been investigated, and the pore characteristics of the waterproof membrane have been studied. Different tests were performed to validate the resulting performance, such as CRH, contact angle (CA), and mercury intrusion porosimetry (MIP). The results showed that at 92 % compaction degree, the consumption of organic silane per unit area (OSA) of 8 g/m2 to 15 g/m2 could effectively inhibit the CRH. The CA of the waterproof membrane increased with OSA consumption and compaction degree. When the compaction degree and OSA consumption increased, the large pores were divided into small pores, resulting in a decrease in the most probable pore size of the waterproof membrane and an increase in the cumulative mesopore volume. Additionally, the specific surface area of the pores and the roughness of the pore surface of the waterproof membrane increased, the pore structure became more complex, and the fractal dimension was closer to 3.]]></description>
      <pubDate>Wed, 18 Sep 2024 09:41:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2409517</guid>
    </item>
    <item>
      <title>Study on single-direction water-blocking of waterproof membrane in silt subgrade</title>
      <link>https://trid.trb.org/View/2398116</link>
      <description><![CDATA[This paper proposes a new concept of single-direction water-blocking for waterproof membranes in silt subgrades to meet the demands of inhibiting capillary rising and allowing subgrade water downward through the waterproof membrane. Furthermore, a new approach to determine the total pore area in water-repellent soil is proposed using a contact angle test. The relationship between the water repellence of the waterproof membrane and the consumption of Sodium Methyl Silicate per unit Area (SMSA) is obtained for different levels of compactness. When SMSA consumption is less than 4 g/m², the water repellence of the waterproof membrane is extremely poor, whereas, in the range of 4–10 g/m², its water repellence is greatly enhanced. When the SMSA consumption is more than 10 g/m2, the water repellence becomes stable. The total pore area of the waterproof membrane decreases when the SMSA consumption is increased.]]></description>
      <pubDate>Tue, 23 Jul 2024 17:43:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2398116</guid>
    </item>
    <item>
      <title>Effect of acylhydrazone self-healing agents with different structures on the properties of SBS modified asphalt waterproofing membrane</title>
      <link>https://trid.trb.org/View/2369853</link>
      <description><![CDATA[To prepare SBS modified asphalt (SMA) waterproofing membrane with excellent self-healing performance, in this paper, four self-healing agents (ASHA-A, ASHA-B, ASHA-C, ASHA-D) with acylhydrazone bonds and carbon-carbon double bonds (CC) were synthesized, and were used to prepare self-healing SMA waterproofing membranes (SSMA-A, SSMA-B, SSMA-C, SSMA-D). The effects of ASHAs with different structures on the structure, high and low temperature properties, joint peel strength and self-healing performance of SSMAs were investigated. The Fourier transform infrared spectroscopy and fluorescence microscope results showed that acylhydrazone bonds of ASHAs were introduced into the chains of SBS molecules, and the SBS in SSMAs occurred crosslinking through the CC of ASHAs and SBS, the crosslinked network structures of SBS in SSMA-C and SSMA-D were denser and more complete because ASHA-C and ASHA-D contained more CC involved in the crosslinking reaction. The softening point and low temperature flexibility of SSMAs were enhanced by the formation of the SBS crosslinked network structure, and the optimum dosage of ASHAs was 0.6%. The joint peel strength of SSMA-A, SSMA-B, SSMA-C and SSMA-D increased by 26.68%, 31.25%, 49.52% and 56.97% compared to SMA. The introduction of acylhydrazone bonds with reversible fracture and rearrangement significantly improved the crack self-healing performance of SMA, the impermeability times of SMA, SSMA-A, SSMA-B, SSMA-C and SSMA-D were 13.28 min, 37.29 min, 42.53 min, 53.34 min and 59.67 min after self-healing at 40℃ for 8 h, which indicated that ASHA-D with benzene ring and multiple CC had the best improvement in self-healing performance of SMA.]]></description>
      <pubDate>Wed, 22 May 2024 16:59:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/2369853</guid>
    </item>
    <item>
      <title>Accelerated evaluation of membranes for pavement structures on orthotropic steel bridge decks</title>
      <link>https://trid.trb.org/View/2310347</link>
      <description><![CDATA[Membranes of sufficient bonding characteristics could improve the integrity of the multi-layer structures on orthotropic steel deck bridges (OSBDs), enhancing thus the structural response of these systems and, ultimately, their service life. In this research, full-scale experiments were performed at the LINTRACK accelerated pavement testing facility of the Delft University of Technology to evaluate the performance of two surfacing systems commonly used in the Netherlands, giving emphasis on assessing the interface response of membranes with the surrounding materials. Results indicated that the tensile strains remain almost uniform at the top of porous asphalt, in both transverse and longitudinal directions, as no appreciable loss in stress-carrying capabilities was seen even at the end of the testing program. The sections exhibited similar behaviour in terms of strains, with some differences in strains indicating the impacts of membranes at interfaces. The importance of membranes of the desired bonding characteristics was also reflected by the relative displacement measurements. The relative interlayer slip had been higher in the transverse direction than the longitudinal one, with slightly higher displacements in one of the test sections. Overall, no cracking was observed on either section, and the current findings support the use of membranes between surfacing layers on OSBDs.]]></description>
      <pubDate>Tue, 09 Apr 2024 18:27:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/2310347</guid>
    </item>
    <item>
      <title>Experimental Study on Influencing Factors Associated with a New Tunnel Waterproofing for Improved Impermeability</title>
      <link>https://trid.trb.org/View/2259047</link>
      <description><![CDATA[Leakage associated with deformation joints seriously affects tunnel structures. Existing tunnel deformation joint waterproofing structures have high construction costs and inconvenient maintenance requirements. This work proposes a new tunnel deformation joint waterproofing structure. Specifically, this structure combines O type water stop, an externally attached water stop, and a concrete component. An impermeability test compares standard waterproofed specimens to improved specimens. Under a variety of deformation joint widths, fatigue loading times, and displacement difference, the variation law of the seepage quantity and impermeability pressure values are obtained. The study also examined the ability of the waterproofing membrane and waterproofing coating to improve on standard practices currently used. The seepage quantity test results indicate a positive correlation of displacement difference and fatigue loading times with seepage quantity. The larger the deformation joint width of the specimen, the more the new construction process demonstrated its ability to resist high fatigue loading times and large displacement differences. As the fatigue loading times increase, the impermeability pressure value of both types of specimens decrease; however, the impermeability pressure value of the improved specimen was less affected, which verifies an increased fatigue resistance. Both waterproofing membranes and waterproofing coatings improve the waterproofing ability of the standard specimen, while the impermeability law demonstrated similar results to the standard process specimen. Ultimately, these findings reveal the value of selecting appropriate deformation joint widths under different practical engineering conditions.]]></description>
      <pubDate>Tue, 31 Oct 2023 10:37:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/2259047</guid>
    </item>
    <item>
      <title>Investigation of Correlation between Component and Molecular Structure of Bitumen and Properties of High-Dosage Styrene-Butadiene-Styrene–Modified Bitumen for Waterproof Membrane</title>
      <link>https://trid.trb.org/View/2125773</link>
      <description><![CDATA[In this article, the correlation between components and molecular structures of base bitumen and properties of high-dosage styrene-butadiene-styrene–modified bitumen (HSMB) for waterproof membrane was investigated. Saturates, aromatics, resins, and asphaltenes (SARA components) of eight base bitumens from different crude oils used to prepare HSMB were analyzed by column chromatography, and the molecular structures of these base bitumens were obtained by proton nuclear magnetic resonance, gel permeation chromatography, elemental analysis, and an improved Brown-Ladner calculation method. Softening point and low-temperature flexibility tests were used to estimate the high- and low-temperature performance of HSMBs. The results showed that the highest softening point of the HSMBs was 119.2°C, whereas the lowest was 102.5°C. The best flexibility of HSMB was -24°C, and the worst was -10°C. The softening point of HSMB raised with the increase of the content of saturates and aromatics, aromatic carbon ratio (fA), and condensation index (CI) while decreasing with the increase of H/C. The flexibility of HSMBs was most significantly influenced by the content of saturates, and when the saturate content was 17 %, the flexibility was optimal. However, the flexibility of HSMB was poor when the number average molecular weight (Mn) of bitumen was large. To prepare HSMB with excellent performance, it is recommended that the content of saturates should be between 12 and 17 %, aromatics content should be between 45 and 55 %, resins and asphaltenes content should not be excessive, and fA &gt; 0.25, CI &gt; 0.17, H/C = 1.55.]]></description>
      <pubDate>Mon, 24 Apr 2023 16:19:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/2125773</guid>
    </item>
    <item>
      <title>Impact of Rumble Strips on Longitudinal Joint Pavement Performance</title>
      <link>https://trid.trb.org/View/2154979</link>
      <description><![CDATA[Milled centerline rumble strips are commonly used to reduce lane departure crashes. Safety benefits of installing rumble strips are viewed as a higher priority than the potential impacts to longitudinal joint performance, often leading to a reduced pavement life. There are several different approaches to minimize the impact that rumble strips may have on joint performance, such as careful selection of pavement candidates for installation of rumble strips, using a sealant on top of the rumble strip (top-down) or using a joint sealer (bottom-up). The objective of this study was to assess the impact of using a void reducing asphalt membrane (VRAM) as a joint sealer on longitudinal joint performance with and without the addition of rumble strips. Laboratory testing was completed on plant mix lab compacted specimens and field cores sampled along the centerline joint of two different roadways. Testing consisted of low and intermediate temperature cracking tests and permeability testing. Results from this study showed that VRAM was effective in mitigating increased permeability concerns with the addition of rumble strips into the pavement surface. In relation to laboratory cracking results, there was no significant difference observed between cracking tolerance index (CT-Index) values with and without rumble strips for cores sampled from one project location, while the second project location showed that CT-Index increased with the presence of the VRAM. Continued monitoring of field sections included in this study and future trial sections will be beneficial in understanding the link between laboratory testing, field performance, and variability associated with centerline joint performance.]]></description>
      <pubDate>Thu, 20 Apr 2023 09:32:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/2154979</guid>
    </item>
    <item>
      <title>Effect of organic attapulgite on properties of SBS modified asphalt waterproofing membranes</title>
      <link>https://trid.trb.org/View/2065459</link>
      <description><![CDATA[In order to improve the aging resistance of styrene butadiene styrene (SBS) modified asphalt waterproofing membranes (SMAWM), in this study, vinyltriethoxysilane grafted attapulgite (VTES-g-ATP) and octadecyl-dimethyl-benzyl-ammonium chloride intercalated attapulgite (ODBA-i-ATP) was prepared, respectively. The effects of VTES-g-ATP and ODBA-i-ATP on properties of SMAWM before and after thermal and ultraviolet aging were investigated. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and loss on ignition test indicated that the cationic surfactant octadecyl-dimethyl-benzyl-ammonium chloride (ODBA) was intercalated into the porous structure of attapulgite (ATP), while the coupling agent vinyltriethoxysilane (VTES) was grafted on the surface of ATP. The water contact angles of ATP, VTES-g-ATP and ODBA-i-ATP were 0°, 50.25° and 72.25°, respectively, revealing VTES-g-ATP and ODBA-i-ATP had better hydrophobicity. Compared to ATP, VTES-g-ATP and ODBA-i-ATP effectively improved the softening point and viscosity and had less effect on the low-temperature flexibility of SMAWM. The results of thermal and ultraviolet aging showed that VTES-g-ATP and ODBA-i-ATP were superior to ATP in enhancing aging resistance of SMAWA, particularly ODBA-i-ATP. FTIR analysis showed that ATP, VTES-g-ATP and ODBA-i-ATP effectively inhibited the oxidative polycondensation of asphalt and the degradation of SBS. Considering the balance of physical properties and aging resistance of modified SMAWM, the ODBA-i-ATP was more suitable as an additive for SMAWM, and the optimal dosage of ODBA-i-ATP in SMAWM is 3.0 wt%.]]></description>
      <pubDate>Tue, 24 Jan 2023 09:31:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/2065459</guid>
    </item>
    <item>
      <title>Evaluation of Performance of Void-Reducing Asphalt Membrane and Tack Coat on Asphalt Mixtures’ Longitudinal Joints</title>
      <link>https://trid.trb.org/View/2089374</link>
      <description><![CDATA[The longitudinal joint is one of the most crucial parts of asphalt pavement construction becuase several types of distress of the pavement can occur if the target density does not meet at the joint. A low density of asphalt pavement causes the pavement at the joint to be more exposed to water penetration, accelerating the rate of deterioration. To address this issue, asphalt agencies use various construction techniques and innovative materials to improve the joint’s performance. Void-reducing asphalt membrane (VRAM) is an innovative adhesive liquid that consists of an asphalt binder, an elastomeric polymer, and a wax modifier. In this study, field cores were collected from an Indiana state road to evaluate the VRAM and tack coat performance at the joint. Semicircular bending Illinois flexibility index (SCB-IFIT) and modified pulloff strength tests were performed to investigate the fatigue resistance and bond strength of VRAM and tack coat at the joint. Digital image analysis confirms that VRAM can migrate up to 15.88 mm (5/8  in.) from the interface. In addition, the pulloff strength test reveals that the interface bonding of the pavement containing VRAM is less than the pavement containing tack coat at low and intermediate temperatures. One of the key findings from the SCB-IFIT test is that the flexibility index of VRAM-containing pavement is around eight times higher than tack coat–containing pavement. Moreover, the fatigue cracking resistance of the VRAM-containing pavement is higher than the laboratory-prepared asphalt mixtures with PG 64-22, PG 70-22, and PG 76-22.]]></description>
      <pubDate>Fri, 30 Dec 2022 09:17:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/2089374</guid>
    </item>
    <item>
      <title>Evaluation and Treatment of Expansive Volcanic Soils US95, Owyhee County, Idaho</title>
      <link>https://trid.trb.org/View/2005220</link>
      <description><![CDATA[Soils at several locations along the first 18.5 miles of US95 in Owyhee County, Idaho, have been found to meet the diagnostic criteria for highly expansive soils. Many of the soils have liquid limits greater than 150 percent, shrinkage limits less than 18 percent, cation exchange capacities greater than 50 cmol/kg, Activity ratios greater than 1.5 and free swells greater than 100 percent. X-ray diffraction shows that the soils contain as much as 60 percent montmorillonite by weight. One-dimensional swell tests of specimens compacted to AASHTO T-99 maximum dry unit weight at water contents near optimum exhibited as much as 30 percent swell when inundated under small surcharge stresses. Swell pressures up to 6 tons/ft² were measured for the compacted soils. The cause of the soil expansion is intake of water into the montmorillonite, an expanding lattice clay mineral. In order for potentially expansive soils to actually swell in an engineered structure, they must initially be in a water deficient condition as a result of stress or climate or both, and then water must become available as a result of a change in the soil’s environment. The water deficient condition of near surface soils in Owyhee County is a result of the semi-arid climate of the region. The annual precipitation in the lower parts of the region averages eleven inches per year and mainly occurs as snowfall. Small amounts of water are therefore made available after pavement construction as result of infiltration of precipitation and concentrated runoff into the exposed but fairly impervious soils. More importantly, water becomes available as a result of changes in the evapotranspiration regime brought about by paving. In semiarid climates with deep water tables, decreased evapotranspiration invariably produces increases in water content of soils beneath covered areas. Pavement heaving resulting from either of the water sources mentioned may take several years to become noticeable. In contrast to the swelling behavior shown by the compacted soils, more or less undisturbed, intact test specimens of the highly plastic Owyhee soils failed to exhibit significant swell or swell pressures upon inundation. It is suggested that the substantially reduced swelling of the impervious soils is due to their untypical origin. Many of the well-known and widely distributed expansive soils of the United States originated from shales formed from weathered basic igneous rocks and tephra deposited in seawater. The expansive soils of Owyhee County are believed to have developed mainly from subaerial hydrothermal alteration and devitrification of welded and slightly welded ignimbrites. The retention of some residual welding and or cementation in the intact material is offered as a possible explanation for the apparent lack of significant swelling. Other factors contributing to the reduced swelling of the undisturbed material are their generally lower insitu unit weights and higher water contents as compared to the remolded and compacted soils. If the results of the laboratory tests on the intact soils are generally applicable to the field, swelling of the Owyhee soils will likely be minimal as long as they can be preserved in an intact, undisturbed condition. When the soils are remolded during construction and when pavement structural sections are to be placed on incoherent colluvial soils of high swelling potential, stabilization techniques will have to be employed to minimize and delay swelling. Standard stabilization methods include chemical treatments to reduce the expanding lattice minerals’ affinity for water and the construction of physical barriers to prevent the ingress of water. The laboratory test program showed that lime is an effective stabilizer of the Owyhee soils, and the treatment did not produce detrimental expansive sulfate reactions even though the soils contain small amounts of gypsum. The use of lime treatment for the Owyhee soils is limited to new pavement construction. Hydraulic barriers in the form of horizontal and vertical membranes coupled with shoulder and ditch paving are recommended for both new construction and existing pavements in areas currently exhibiting distress. While these measures cannot prevent all future swelling of the potentially expansive pavement subgrades, they will reduce the amount of swelling and delay its occurrence.]]></description>
      <pubDate>Sun, 28 Aug 2022 17:29:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2005220</guid>
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