<?xml version="1.0" encoding="utf-8"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>TRB Publications Index</title><link>http://pubsindex.trb.org/</link><atom:link href="http://pubsindex.trb.org/common/TRIS Suite/feeds/rss.aspx?tc=NN%3ARkmaa" rel="self" type="application/rss+xml" /><description></description><language>en-us</language><copyright>Copyright © 2015. 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>TRB Publications Index</title><url>http://pubsindex.trb.org/Images/PageHeader-wTitle.png</url><link>http://pubsindex.trb.org/</link></image><item><title>Impact of Fatigue Exposure on Extensibility Performance of Standard Joint Reservoir and Sealant Designs for Jointed Plain Concrete Pavements</title><link>http://pubsindex.trb.org/view/2681414</link><description><![CDATA[The transverse joint sealant for a jointed plain concrete pavement (JPCP) minimizes the entry of moisture, deicing salts, and incompressibles. This reduces the potential for the development of durability issues, erosion, pumping, faulting, spalling, and blow-ups. Sealant performance is influenced by sealant material, joint reservoir design, and the timing and quality of the installation. A laboratory study was performed to evaluate three joint design/material combinations subjected to simulated joint opening/closing and vehicle load fatigue that would occur in a 15 ft JPCP throughout a 42-year service life and freeze-thaw cycles. Data collected from an instrumented pavement was used to establish the loading conditions throughout the 42 years. Extensibility testing was performed on newly sealed joints as well as sealed joints with the simulated service life loadings to assess the performance. The adhesive strength for the asphalt sealed joints (26 pounds per square inch [psi]) was found to be statistically significantly higher than the silicone sealed joints (22 psi). Additionally, it was observed that asphalt filled joints exhibited substantial cohesive failures because of the narrow joint width and the difficulty in adequately filling the joint. From these results, it was concluded that silicone and asphalt sealant material and reservoir designs are sufficient to achieve long-term performance for 15 ft JPCPs for the JPCP design and environmental conditions considered, while asphalt filled joints are recommended for shorter slabs. These results assume that all joints are activated before sealing to prevent over- and under-filling of the joints, which can lead to premature sealant failure.]]></description><pubDate>Fri, 20 Mar 2026 08:38:25 GMT</pubDate><guid>http://pubsindex.trb.org/view/2681414</guid></item><item><title>Effects of Shape and Bond Strength on Adhesive Failure of Joint Sealants</title><link>http://pubsindex.trb.org/view/1751877</link><description><![CDATA[Currently, joint sealant is designed without consideration of the bond strength between the concrete and the sealant and the effect of shape on stress concentration. This often leads to adhesive failures within 1.5?years, earlier than the expected service life of the joint sealant, which is 20?years. In adhesive failure, the strength of the bond and the stress of the interface between the sealant and the face of the joint reservoir play a very important role. To examine the nature of the bond along the sealant/joint well interface, experimental bond tests were conducted. In addition, the stress distribution on the interface was also investigated according to geometry (Shape Factor [SF] and degree of curvature [DoC]). Re-evaluation of the SF was conducted, and a new design factor, DoC, was introduced and investigated through the finite element method of analysis. With these factors, the reduction of bond strength and increase in the stress at the interface can be limited reducing the potential for early adhesive failure. Based on this study, the effect of joint preparation (dirt and moisture) on joint strength and shape (SF and DoC) of joint sealant should be considered when designing and installing sealants.]]></description><pubDate>Wed, 18 Nov 2020 13:54:04 GMT</pubDate><guid>http://pubsindex.trb.org/view/1751877</guid></item><item><title>Investigation of Crack Sealant Adhesive Properties Considering Complex Service Ambient Conditions Based on Weak Boundary Layer (WBL) Theory</title><link>http://pubsindex.trb.org/view/1572349</link><description><![CDATA[Crack sealant is an effective, simple and extensive maintenance approach for repairing cracks all over the world. However, extended exposure of sealants to complex ambient conditions have shown to negative impact on sealants properties, causing gradual degradation of sealant performance even seriously premature failure during their service. According to fracture modes of the failure interface, it is found that the weak boundary layer indeed exists and results in adhesive failure of the crack sealant. This paper presented three harmful environmental factors, namely temperature, water and impurity, to investigate the effect of hostile ambient exposure on different crack sealants commonly used in hot and moderate climates. Tensile test was the main evaluation method and the Weak Boundary Layer (WBL) theory was introduced to illustrate the adhesion failure between sealant and crack wall. The analysis of the experimental results showed that the lower temperature, the longer soaking time and the impurities would precipitate the occurrence of weak boundary layer. Among which, sealant was in the glassy state and likely to arise brittle fracture at the interface at -30 °C. When soaking for a long time, sealant would become harden gradually, and water could penetrate into the pores on the adhesive surface of the crack wall. Impurities at the interface would hinder the adhesive and reduce the contact area between sealant and crack wall. So that the adhesion property between the interfaces would drop sharply and thus caused adhesion failure.]]></description><pubDate>Fri, 01 Mar 2019 15:50:54 GMT</pubDate><guid>http://pubsindex.trb.org/view/1572349</guid></item><item><title>Study of Interface Adhesive Strength Between Porous Polyurethane Mixture and Asphalt Sublayer</title><link>http://pubsindex.trb.org/view/1495984</link><description><![CDATA[This study aims to study interface shear strength between porous polyurethane mixture and asphalt mixture with different adhesive materials. The purpose is to illustrate the necessity of applying adhesive materials between porous polyurethane mixture and asphalt sublayer. Polyurethane, epoxy resin, and SBS modified asphalt were selected as adhesive materials to fabricate composite specimens. Interface shear strength of composite specimen was measured using inclined shear test at different temperatures and freezing-thaw conditions. The shear fatigue life of composite specimen with different adhesive materials was also investigated. The results indicated: it is necessary to set adhesive material between Porous Polyurethane Mixture and asphalt mixture  since its interface shear strength (without adhesive material) was smaller than the shear strength produced by two layers of asphalt concretes; The epoxy resin had better performance of shearing resistance than SBS modified asphalt and polyurethane at 25?, but the three adhesive materials have the similar shear strength at both -18? and 60?; After the freeze-thaw cycle, the shear strength of all the specimens decreased, and this reduction of SBS modified asphalt was the minimum; As for the inclined shear fatigue test, the epoxy resin had the longest fatigue life and SBS modified asphalt was the lowest.]]></description><pubDate>Wed, 28 Feb 2018 09:26:11 GMT</pubDate><guid>http://pubsindex.trb.org/view/1495984</guid></item><item><title>Proposed Approach for Evaluation of Cohesive and Adhesive Properties of Asphalt Mixtures for Determination of Moisture Sensitivity</title><link>http://pubsindex.trb.org/view/1403770</link><description><![CDATA[Moisture damage to asphalt pavements continues to be a major concern after decades of research. Two of the most common moisture failure modes in asphalt mixtures are adhesive failures between the aggregate and binder and cohesive failures in the binder or mastic. The challenge in conditioning asphalt mixtures for moisture sensitivity is developing a test method that is capable of evaluating adhesive and cohesive failure properties while remaining repeatable, accurate, and practical. There are three methods for conditioning an asphalt mixture for determining moisture sensitivity: AASHTO T 283, ASTM D4867, and ASTM D7870. T 283 is the most common method for evaluating moisture damage. The conditioning involves saturating, followed by freezing–thawing conditioning of specimens to induce pore pressure. D7870 is the moisture-induced stress test (MIST), which dynamically induces pore pressure into the specimen. In this study, both of these conditioning methods were evaluated with a known moisture-resistant mixture and known moisture-sensitive mixture. The different conditioning methods were evaluated with the tensile strength ratio, change in density, and visual inspection. Results show that the most effective method of conditioning to capture moisture-sensitive mixtures is a combination of T 283 and D7870. T 283 accentuates adhesive failures while D7870 accentuates cohesive failure in the mixtures. The proposed conditioning method uses the MIST unit to effectively identify cohesive and adhesive moisture-sensitive mixtures during mixture design and quality control of asphalt pavements.]]></description><pubDate>Thu, 14 Apr 2016 11:55:50 GMT</pubDate><guid>http://pubsindex.trb.org/view/1403770</guid></item><item><title>Investigating Effects of Water Conditioning on Adhesion Properties of Crack Sealant</title><link>http://pubsindex.trb.org/view/1339486</link><description><![CDATA[Even though sealants are commonly used to insulate crack and joints preventing water from entering the underlying structure, extended exposure of sealants to water has shown to negatively impact sealants properties causing gradual degradation of its performance. However, sealants show different degradation rates when exposed to water depending on their chemical composition and environmental conditions. While there have been many studies on characterizing sealant performance in dry conditions, there has been no comprehensive experimental test to evaluate crack sealants' water susceptibility based on a fundamental material property. As such this paper investigates the effect of water exposure on three different crack sealants commonly used in cold, moderate and hot climates. It is hypothesized that water penetrates into the interface between crack sealant and substrates causing progressive adhesion failure and that the rate of failure varies depending on the sealant’s surface chemistry as related to its interaction with water molecules in different environmental conditions. Accordingly, this paper measures the change in a sealant’s adhesion strength and surface energy before and after water conditioning. To study adhesion strength and its change due to water conditioning, three different types of sealant were tested using Direct Adhesion Tester (DAT). It was found that the adhesion strength of all three crack sealants reduces due to water exposure. In addition, to evaluate the surface properties and water phobicity of each sealant, the contact angle between a droplet of water and sealant surface was measured before and after conditioning at different temperatures. The objective of the latter experiment was to determine whether sealants' susceptibility to water would vary with pavement surface temperature. To do so, a sessile drop method utilizing FTA-1000 was used to determine the contact angle for each of the aforementioned water-sealant pairs at different temperatures. The results obtained were further used to calculate the work of adhesion at each scenario to be correlated to mechanical adhesion strength measured with DAT.]]></description><pubDate>Mon, 16 Mar 2015 16:41:43 GMT</pubDate><guid>http://pubsindex.trb.org/view/1339486</guid></item><item><title>Adhesion Evaluation of Duplex Paint System for Sustainable Infrastructure</title><link>http://pubsindex.trb.org/view/1338903</link><description><![CDATA[Steel structures such as highway bridges, walkway railings are painted with organic coatings to provide aesthetic appeal and corrosion resistance. In a duplex system organic paints are applied to galvanized or  metalized steel surfaces. The duplex system is potentially more sustainable than the zinc-rich primer/steel system due to its longer lasting corrosion resistance. A perceived weakness of the duplex system is that the paint adhesion on the metallic zinc is harder to achieve. In order to understand factors influencing the paint adhesion on galvanized or metalized steel, a series of experimental tests were performed for adhesion strengths of 4 different paints and 3 different types of roughened zinc surfaces on 84 test panels. The contact angles were also measured for freshly formulated liquid paints on the roughened zinc surfaces to test if there is a correlation between the paint wetting property and the adhesive strength. By comparing duplex system and zinc-rich primer/steel qualified by Northeast Protective Coating Committee (NEPCOAT), it was found the paint adhesion of duplex system is as strong as the zinc primer/steel panels based on test results with the ASTM D4541 procedure. It was also found that adhesive strengths depend on the match between the paint and type of roughened zinc surfaces. The measurement of liquid paint wetting properties indicates potential correlation between contact angle and the pull-off adhesive strength. It has been suggested that contact angle/strength correlation could be useful as a tool for optimizing the match between paints and the profiled zinc surfaces.]]></description><pubDate>Mon, 23 Feb 2015 09:21:34 GMT</pubDate><guid>http://pubsindex.trb.org/view/1338903</guid></item><item><title>Investigation of Joint Surface Preparation Effects on Silicone Sealant Using a New Testing Procedure</title><link>http://pubsindex.trb.org/view/1129539</link><description><![CDATA[A new laboratory testing method was developed to quantify the adhesive strength between concrete and sealant. The new method was used to quantify the effects of surface preparation on adhesive strength.  A number of samples were tested under artificial roughness and debris-induced conditioned.  For roughened samples, an Aggregate Imaging Measurement System (AIMS) was used to quantify roughness.  Results appear to indicate that an optimal roughness may be achieved where adhesive strength is maximized.  Debris-induction tended to reduce adhesive strength, and debris effects were observed to be most severe under higher induced roughness conditions.]]></description><pubDate>Fri, 15 Jun 2012 16:04:39 GMT</pubDate><guid>http://pubsindex.trb.org/view/1129539</guid></item><item><title>Correlation of Moisture Loss and Strength Gain in Chip Seals</title><link>http://pubsindex.trb.org/view/1092146</link><description><![CDATA[One of the most subjective decisions made during chip seal construction concerns when to allow brooms and traffic on the newly placed surface. If traffic is allowed too early, damage to the surface and to vehicles may occur. If the chip seal is opened too late, traffic is disrupted and motorists are inconvenienced. The curing of asphalt emulsions in the field is related to many factors, all affecting how fast the asphalt emulsion cures. Three laboratory test methods that measure adhesive strength gain as a function of moisture loss are presented. Two of the methods were sweep tests, one performed according to ASTM D7000 and the other according to a modified method. The third test used frosted marbles to measure adhesive strength gain. Results of all tests were similar and indicated that strength in emulsion residues increased as the total moisture in the system was reduced. This finding is important because the moisture content is independent of the mechanism reducing it. Therefore, prediction of strength gain should be possible by measurement of the moisture loss of a given chip seal system. The time required to obtain that strength gain varies in seals because of differences in emulsion, aggregate, interaction factors, weather, ambient temperature, and other environmental factors. Test results indicated that as moisture loss approached 75% to 90%, strength gain was significantly enhanced.]]></description><pubDate>Tue, 19 Apr 2011 07:16:46 GMT</pubDate><guid>http://pubsindex.trb.org/view/1092146</guid></item><item><title>Repair and Retrofit Anchorage Designs for Two Texas Department of Transportation Bridge Rails</title><link>http://pubsindex.trb.org/view/802160</link><description><![CDATA[A project was focused on developing alternative rail anchorage systems for the Texas Department of Transportation’s T501 and T203 bridge rail systems. The project considered only epoxy adhesive anchoring systems for each of these railings for use in repair and retrofit situations. Full-scale testing was performed on both rail types, and strength data were obtained with instrumented strain gauges on the rail anchorage for both rail types. These data were analyzed and used to develop alternate rail anchorage systems for both T501 and T203 bridge rails. Long-term durability of epoxy anchoring systems was also considered. The retrofit–repair strengths from the dynamic and static testing for both the T501 and the T203 compared closely to the dynamic and static strengths of the current strengths capacities. In summary, the strengths of the retrofit designs were close to and in some tests exceeded the calculated capacities of the bridge rails. The static strengths were close to the dynamic 50-ms average strengths recorded from the bogie testing. The new retrofit–repair designs developed and tested for this project are recommended for implementation for use on any new or existing bridge projects. The use of the Hilti RE 500 adhesive anchoring system was successful in achieving the strengths needed to adequately anchor the retrofit–repair reinforcement for both the T501 and the T203 bridge rails. The information learned from this project can be used to retrofit and repair other bridge rail designs in the future.]]></description><pubDate>Tue, 10 Apr 2007 09:22:29 GMT</pubDate><guid>http://pubsindex.trb.org/view/802160</guid></item><item><title>Limits on Adhesive Bond Energy for Improved Resistance of Hot-Mix Asphalt to Moisture Damage</title><link>http://pubsindex.trb.org/view/776906</link><description><![CDATA[The loss of physical adhesion between the aggregate and the asphalt binder is one of the important mechanisms that accelerate moisture damage in hot-mix asphalt pavements. In this study, two parameters related to bond energy—adhesive bond energy between the aggregate and the asphalt and reduction of free energy when asphalt debonds from the aggregate surface in the presence of moisture—were quantified with surface energies of both materials. Threshold values of these parameters to identify asphalt–aggregate combinations susceptible to premature moisture damage were derived by comparison of the values of these parameters with observed field performance for several mixes. Results show significant differences in bond energies developed between various aggregates and a given binder. This finding illustrates the importance of binder–aggregate compatibility and the sensitivity of calculated bond strength to surface energy measurements. Asphalt binders from different sources with the same performance grade were also found to develop different bond energies with any given aggregate. The results show that binders differ in their sensitivity to changes in aggregate source in terms of the developed bond energy. The methodology of using surface energy and concomitant bond energy calculations to assess the moisture sensitivity of asphalt concrete mixes is discussed as well as the advantages of using this technique compared with conventional mechanical tests.]]></description><pubDate>Wed, 31 May 2006 07:54:24 GMT</pubDate><guid>http://pubsindex.trb.org/view/776906</guid></item><item><title>CONTROL OF THE PLASTICITY INDEX OF SOIL-AGGREGATE MATERIALS USING HAND-FEEL TESTS</title><link>http://pubsindex.trb.org/view/121425</link><description><![CDATA[THREE COMMONLY USED HAND-FEEL OR EXPEDIENT TESTS WERE USED IN THIS STUDY - THREAD TOUGHNESS NEAR PLASTIC LIMIT, DRY STRENGTH, AND REACTION TO SHAKING. A NUMERICAL SCALE OF 0 TO 3 WAS APPLIED TO THE RANGE OF RESULTS FOR EACH OF THE TESTS TO PERMIT ANALYSIS OF CORRELATION WITH PLASTICITY INDEX. ON 58 BANKRUN GRAVELS FROM NEW YORK STATE, THE HAND-FEEL RESULTS OF AN EXPERIENCED TECHNICIAN CORRELATED WELL WITH PLASTICITY INDEX. THE SUM OF NUMERICAL RATINGS ON THE THREE TESTS MAY BE AS USEFUL AN INDICATOR OF PI AS THE RESULTS OF MULTIPLE REGRESSION. FOR THIS TECHNICIAN, THE LINEAR REGRESSION OF PI ON THE SUM OF THREAD TOUGHNESS (T.T.), DRY STRENGTH (D.S.), AND REACTION TO SHAKING (DIL.) RATINGS WAS PI = -2.4 + 0.99 (T.T. + D.S. + DIL.). THE CORRELATION COEFFICIENT WAS 0.917 (R SQUARED = 0.841) AND THE STANDARD ERROR OF ESTIMATE FOR PI WAS 0.97. THE RELATIONSHIPS BETWEEN RESULTS OF THE HAND-FEEL TESTS AND LIQUID LIMIT WERE LESS STRIKING THAN THE RELATIONSHIPS WITH PLASTICITY INDEX. A STUDY OF HAND-FEEL RATINGS BY INEXPERIENCED PERSONS SUGGESTED THAT SOME COACHING WOULD BE NECESSARY FOR REASONABLE CONSISTENCY IN RESULTS. /AUTHOR/]]></description><pubDate>Sun, 15 Aug 2004 02:39:19 GMT</pubDate><guid>http://pubsindex.trb.org/view/121425</guid></item><item><title>CHEMICAL AND MECHANICAL PROCESSES OF MOISTURE DAMAGE IN HOT-MIX ASPHALT PAVEMENTS</title><link>http://pubsindex.trb.org/view/689652</link><description><![CDATA[Historically, six contributing mechanisms to moisture damage have been identified:  detachment, displacement, spontaneous emulsification, pore pressure-induced damage, hydraulic scour, and the effects of the environment on the aggregate-asphalt system.  However, it is apparent that moisture damage is usually not limited to one mechanism but is the result of a combination of processes.  It has become necessary to seek a more fundamental understanding of the moisture damage process by carefully considering the micromechanisms that influence the adhesive interface between aggregate and asphalt and the cohesive strength and durability of the mastic.  Factors that influence the adhesive bonds in asphalt mixtures and the cohesive strength of the mastic in the presence of water are presented and discussed as a fundamental approach to calculating adhesive bond strength in asphalt mixtures in the presence of water on the basis of surface free energy measurements.  The adhesive bond that determines the durability of asphalt mixtures in the presence of water is described in this paper to be based on a nonuniform distribution of charges in the asphalt and on the aggregate surface.  The polar compounds in the asphalt that react with the aggregate polar sites determine the strength and durability of the adhesive bond.  Several processes are presented that affect this bond.  The effect of aggregate mineralogy, surface properties, and the pH at the water-aggregate interface is discussed.]]></description><pubDate>Thu, 26 Feb 2004 00:00:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/689652</guid></item></channel></rss>