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    <title>Transport Research International Documentation (TRID)</title>
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    <atom:link href="https://trid.trb.org/Record/RSS?s=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" 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>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Efficient inactivation of bacteria in ballast water by adding potassium peroxymonosulfate alone: Role of halide ions</title>
      <link>https://trid.trb.org/View/1765445</link>
      <description><![CDATA[In recent years, ballast water disinfection has been paid much more attention due to the untreated discharged ballast water posing threat of biological invasion and health related consequences. In this study, an effective and simple approach for ballast water disinfection by just adding potassium peroxymonosulfate (PMS) was assessed, and the role of halide ions in seawater on the enhancement of inactivation was revealed. The reactive species responsible for inactivation, the leakage of intracellular materials, and changes of cellular morphology after inactivation were evaluated to explore the inactivation mechanism. The results showed that Escherichia coli and Bacillus subtilis in ballast water could be totally inactivated within 10 min by adding 0.2 mM PMS alone. The inactivation of bacteria in ballast water fitted to the delayed Chick-Watson model. Chloride and bromide ion in seawater were found to play a crucial role in inactivating bacteria, while the effect of iodide ion could be negligible due to its relative lower concentration in seawater. Chlorine and bromine, produced by the reaction of PMS with chloride and bromide ion, were proved to be the main reactive components that were responsible for the inactivation of bacteria. The extracellular ATP and total nitrogen concentration increased after inactivation which indicated that cell membrane was destroyed by reactive oxidants produced by the reaction between PMS and halide ions. The change of cell morphology confirmed that bacteria were seriously damaged after inactivation. The results suggest that PMS is an attractive alternative disinfectant for ballast water disinfection and this application deserved further research.]]></description>
      <pubDate>Sun, 28 Feb 2021 16:51:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/1765445</guid>
    </item>
    <item>
      <title>Efficient inactivation of bacteria in ballast water by adding potassium peroxymonosulfate alone: Role of halide ions</title>
      <link>https://trid.trb.org/View/1721322</link>
      <description><![CDATA[In recent years, ballast water disinfection has been paid much more attention due to the untreated discharged ballast water posing threaten of biological invasion and health related consequences. In this study, an effective and simple approach for ballast water disinfection by just adding potassium peroxymonosulfate (PMS) was assessed, and the role of halide ions in seawater on the enhancement of inactivation was revealed. The reactive species responsible for inactivation, the leakage of intracellular materials, and changes of cellular morphology after inactivation were evaluated to explore the inactivation mechanism. The results showed that Escherichia coli and Bacillus subtilis in ballast water could be totally inactivated within 10 min by adding 0.2 mM PMS alone. The inactivation of bacteria in ballast water fitted to the delayed Chick-Watson model. Chloride and bromide ion in seawater were found to play a crucial role in inactivating bacteria, while the effect of iodide ion could be negligible due to its relative lower concentration in seawater. Chlorine and bromine, produced by the reaction of PMS with chloride and bromide ion, were proved to be the main reactive components that were responsible for the inactivation of bacteria. The extracellular ATP and total nitrogen concentration increased after inactivation which indicated that cell membrane was destroyed by reactive oxidants produced by the reaction between PMS and halide ions. The change of cell morphology confirmed that bacteria were seriously damaged after inactivation. The results suggest that PMS is an attractive alternative disinfectant for ballast water disinfection and this application deserved further research.]]></description>
      <pubDate>Tue, 01 Dec 2020 09:52:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/1721322</guid>
    </item>
    <item>
      <title>Effective Light Source for Illuminating Overhead Guide Signs and Improving Roadway Safety</title>
      <link>https://trid.trb.org/View/1662219</link>
      <description><![CDATA[Driver safety is considered an important issue to departments of transportation. One way to increase highway safety is to improve the visibility of overhead guide signs for drivers. Visibility improving methods include the use of sign illumination or retroreflective sheeting materials. This paper focuses on sign illumination by comparing five light sources including high pressure sodium (HPS), metal halide (MH), mercury vapor (MV), induction lighting, and light emitting diode (LED). A laboratory experiment was conducted to compare effective light distribution of each light source and a cost analysis was performed to compare initial, maintenance, and operating cost components of the light sources. Results of the light distribution experiment indicated that HPS was the optimum light source followed by MH, induction lighting, MV, and LED. Induction lighting is a promising lighting technology which features good efficiency and long life. According to cost analysis, induction lighting was the most effective source, followed by the LED, HPS, MV, and MH. Of the five light sources considered, induction lighting provided the best overall performance when considering initial cost, operating cost, expected maintenance, and sign illuminance. Environmentally, LED does not contain mercury, and for those agencies that prefer using sources that are friendlier with the environment, the LED can be their best choice.]]></description>
      <pubDate>Thu, 02 Apr 2020 09:43:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/1662219</guid>
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    <item>
      <title>Non-saturated ion diffusion in concrete - A new approach to evaluate conductivity measurements</title>
      <link>https://trid.trb.org/View/1681620</link>
      <description><![CDATA[Non-saturated ion diffusion properties of cementitious materials were evaluated in an experimental study. To assess these properties, resistivity measurements have been performed on mortars with different binders (ordinary Portland cement - OPC, OPC with 5% silica fume, 40% slag and 70% slag, respectively) and different water-to-binder ratios (w/b, 0.38 and 0.53). Specimens have been conditioned to eight different climates with relative humidity (RH) from 100% to 33% RH in order to assess an effective diffusion coefficient. The results from the resistivity measurements have been corrected for changes of the conductivity of the pore solution when drying to different degrees of saturation. The diffusion coefficients for Portland cement binders within the range 100-59% RH are presented. They showed that the diffusion coefficient of the mortar with high w/b ratio was higher at high RH, but at low RH the opposite trend was found. By comparing these results with the corresponding desorption isotherms, it is shown that the diffusion coefficient for the two w/b ratios have the same dependency on the degree of saturation.]]></description>
      <pubDate>Tue, 28 Jan 2020 16:15:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/1681620</guid>
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    <item>
      <title>Sensitivity analysis of chloride ingress models: Case of concretes immersed in seawater</title>
      <link>https://trid.trb.org/View/1491733</link>
      <description><![CDATA[Reinforced concrete structures exposed to a marine environment deteriorate as a result of chloride-induced corrosion of the steel rebars. A wide variety of models to predict chloride ingress in water-saturated concretes have already been developed to understand and predict the underlying transport processes. The majority of these models focus on the initiation period of chloride-induced corrosion in order to predict the service life of reinforced concrete structures. They require information on the concrete properties, the concrete cover thickness, the definition of corrosion initiation, etc. These models combine well-known mechanisms, i.e. diffusion of relevant ions, electrical interactions between ions, and interactions between these ions and the solid matrix. As the mechanisms to consider are well identified, the objective here is to perform a probabilistic analysis of some common models. A general framework is proposed to calculate a reliability service life for reinforced concrete structures under chloride attack in case of continuous immersion in seawater. Then a sensitivity analysis is performed in terms of the most relevant mechanisms and influencing input data. The results point out the crucial role of the concrete cover thickness, the critical chloride content and, to a lesser extent, the effective chloride diffusion coefficient. The difficulty to use the Freundlich isotherm for chloride binding is highlighted; it seems to be due to the non-linearity of the description which is still difficult to control.]]></description>
      <pubDate>Thu, 14 Dec 2017 15:53:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/1491733</guid>
    </item>
    <item>
      <title>Chloride ingress and steel corrosion in slag and fly ash blended geopolymer concrete</title>
      <link>https://trid.trb.org/View/1467966</link>
      <description><![CDATA[Alkali activated binders (geopolymer) is an emerging technology to produce concrete without the use of any Ordinary Portland Cement (OPC) by alkali activation of alumino-silicate source materials such as fly ash and/or slag. Limited knowledge on durability issues like corrosion behaviour of reinforced geopolymer concrete impedes the usage of this technology in structural applications. This study explored the chloride permeability and initiation of chloride induced corrosion of geopolymer concrete in accelerated chloride environment using longer test period. Corrosion state of the rebar was monitored using nondestructive test method using Cu/CuSO4 reference electrode. The results showed that the apparent chloride diffusion coefficient of blended fly ash and slag geopolymer concrete is lower than that of OPC concrete. The diffusion coefficient also decreased with the increase of slag content in the binder. Blended fly ash and slag geopolymer concrete also exhibited higher aging factor than OPC concrete indicating improved resistance to chloride ingress with time. The study also showed that the embedded rebar in fly ash and slag based geopolymer concrete has higher protection against corrosion than a rebar in OPC concrete.]]></description>
      <pubDate>Wed, 24 May 2017 14:00:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/1467966</guid>
    </item>
    <item>
      <title>Comparison of existing chloride ingress models within concretes exposed to seawater</title>
      <link>https://trid.trb.org/View/1460336</link>
      <description><![CDATA[Numerous models to predict chloride ingress within concretes for different environmental conditions (immersed in seawater, located in the tidal zone or exposed to sea spray) have already been developed. Thanks to a benchmark, the objective of this paper is to contribute to the choice of a reliable engineering model for predicting chloride ingress in the case of saturated conditions. This study focus on a comparison between various physico-chemical models which rely on different approaches to account for transport phenomena and binding of chloride ions onto the cementitious matrix. The authors draw special attention to models using a limited number of input data (3 or 4): accessible-to-water porosity, effective chloride diffusion coefficient and one or two parameter(s) characterizing the physical binding of ions Cl-. They are determined through the analysis of two simple and repeatable experimental tests: the porosity is measured directly by hydrostatic weighing and the other parameters are fitted by inverse analysis performed of a total chloride content (tcc) profile at a given exposure time. An application of the method and a comprehensive comparison between predicted chloride profiles and experimental data (tcc profiles at other ages than the one used for the fitting and free chloride concentration profiles) have been carried out for two mortars and seven concretes exposed to laboratory or in-situ conditions. The performance of the studied models is assessed thanks to statistical tools and recommendations are pointed out for the development of new numerical models.]]></description>
      <pubDate>Fri, 17 Mar 2017 10:37:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/1460336</guid>
    </item>
    <item>
      <title>Mathematical relation of steel thickness loss with time related to reinforced concrete contaminated by chlorides</title>
      <link>https://trid.trb.org/View/1460295</link>
      <description><![CDATA[Corrosion of chloride contaminated reinforced concretes exposed to outdoor conditions and to six controlled environmental conditions was followed within a five year study. Corrosion was evaluated four times a year performing visual observations (rust, cracks, delamination) and electrochemical measurements from which corrosion rates were calculated. These latter values were converted in cumulative steel thickness loss versus cumulative time in order to propose a mathematical relation for simulating corrosion in the propagation phase. It was found that a mathematical power relation fitted the experimental data better than a linear relation.]]></description>
      <pubDate>Fri, 17 Mar 2017 10:36:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/1460295</guid>
    </item>
    <item>
      <title>In situ and laboratory testing of different repair materials</title>
      <link>https://trid.trb.org/View/1394982</link>
      <description><![CDATA[The Maastunnel in Rotterdam has to be renovated to ensure service life for a few more decades. The concrete of the tunnel is deteriorated. Chloride from deicing salts has penetrated into the concrete and has reached such levels in the material that the reinforcement is heavily corroded. Furthermore the concrete cover has spalled off and disappeared in large sections of the tunnel, especially in the floor of the tunnel. The cross section of the reinforcing bars at those places is also heavily decreased. The intention is now to perform a repair of the cover-zone concrete which will last for the remaining service life of the tunnel without any or limited maintenance. In the Microlab at Delft University several novel repair materials are developed which are based on fibre reinforced cementitious composites. The new materials enable a good bond with the old concrete and have a crack distributing capability. Furthermore, if the reinforcement bars continue to corrode, the repair material will not fail because it can to a certain extent cope with the imposed strain by the expanding bars. With these materials several patches are repaired inside the tunnel and laboratory specimens for property testing and accelerated corrosion tests are prepared. The paper compares and discusses the performance of the different repair materials in situ and the results of the laboratory testing.]]></description>
      <pubDate>Thu, 14 Jan 2016 09:46:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/1394982</guid>
    </item>
    <item>
      <title>A resistivity-based approach to indicate chloride permeability of geopolymer concrete</title>
      <link>https://trid.trb.org/View/1394981</link>
      <description><![CDATA[Chloride ion penetration in concrete is one of the major causes of deterioration of reinforced concrete structures by depassivation of reinforcing bars. Since testing of the natural chloride penetration is time consuming, utilising an accelerated test method is more desirable. Surface resistivity (SR) test is increasingly being used, due to its relative speed and ease of performing combined with the nondestructive nature, to assess the permeability of concrete and its resistance to chloride ion penetration. The test has been standardised as AASHTO TP 95 which consists of measuring the resistivity of water-saturated concrete cylinders using a four-pin Wenner probe array. This paper present the results of an experimental investigation on the surface resistivity (SR) of a low-calcium fly ash-based geopolymer concrete (GPC). SR test results show that the resistivity of GPC samples are very low, this does not necessarily mean that they are having a high level of chloride penetrability since the AASHTO TP 95 limits are only applicable for conventional OPC concrete and not for the GPC. In case of geopolymer concrete, there are a large amount of mobile metallic ions such as Na+ in the pore solution which could probably affect the resistivity test measurements. A further study is required to directly measure the chloride permeability of the GPC such as natural diffusion or ponding test to be able to properly correlate the surface resistivity measurements of GPC to its actual chloride permeability level.]]></description>
      <pubDate>Thu, 14 Jan 2016 09:46:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/1394981</guid>
    </item>
    <item>
      <title>Durability assessment of concrete immersed tube tunnel in Hong Kong-Zhuhai-Macau sea link project</title>
      <link>https://trid.trb.org/View/1394978</link>
      <description><![CDATA[The concrete immersed tube tunnel in the Hong Kong-Zhuhai-Macau (HZM) sea link project was designed for a service life of 120 years. The concrete tunnel is exposed externally to the sea water and internally to traffic and marine air. This paper reviews the durability design of this concrete sea tunnel and the key durability parameters retained for the structural concrete. During the construction, the concrete properties were tested in the laboratory and nondestructive tests were performed on the prefabricated segments of concrete tube. The quality of structural concrete is evaluated on the basis of these in-situ data and their statistical properties. Further the achieved durability of the immersed tube tunnel is assessed though Fick’s law for chloride ingress via a fully probabilistic approach. The safety margin for structural durability is represented in terms of failure probability and reliability index. Based on the durability assessment in construction phase, a preliminary maintenance planning is given taking into account the accidental working case of sea water infiltration.]]></description>
      <pubDate>Thu, 14 Jan 2016 09:45:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/1394978</guid>
    </item>
    <item>
      <title>Exp-Ref: a simple, realistic and robust method to assess service life of reinforced concrete structures</title>
      <link>https://trid.trb.org/View/1394977</link>
      <description><![CDATA[The hereby proposed 'Exp-Ref' method of Service Life Assessment presents two characteristic features. First, it is 'Experimental', because the prediction is based on the 'in situ' ND determination of the cover depth d and of the coefficient of air-permeability kT. Second, the assessment is not based on a prediction starting from t=0 as most other methods, but from a 'Reference' condition corresponding to 50 years. This is the service life expected if the prescriptions of concrete quality (EN206-1 and EN 13670) and cover depth (Eurocode 2) are observed. By comparing the actual values of d and kT measured on site with those corresponding to the reference condition, it is possible to estimate the service life (SL) with a simple formula. The proposed method is simple and realistic (is based on real data obtained on the end-product, referred to values for 50 years of SL) and is robust (neither ambiguities nor subjectivity by selective choice of model parameters as for other methods). It provides also a probabilistic representation of SL as a single value is assigned to each measurement point. A couple of application cases are presented.]]></description>
      <pubDate>Thu, 14 Jan 2016 09:45:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/1394977</guid>
    </item>
    <item>
      <title>Determination of chloride diffusion coefficient of concrete: comparison of bulk diffusion and electrical field method</title>
      <link>https://trid.trb.org/View/1394975</link>
      <description><![CDATA[Chloride diffusion coefficient of concrete is of prime importance in the service-life prediction for concrete structures, and it can also be used as a parameter for the concrete quality control. This paper presents the results of chloride diffusion tests in which the diffusion coefficient was determined by the two most commonly used acceleration methods; the bulk diffusion in solution of high chloride concentration, and the electric field accelerated migration test. Two types of concrete mixes were used, one being of 40 MPa strength grade, containing plain Portland cement as binder, and the other of 50 MPa strength grade which contained blended cement as binder. This paper shows that the value of diffusion coefficients determined by the bulk diffusion test is considerably higher than that obtained on concrete structure exposed to seawater, and the value of diffusion coefficient determined by migration test under electrical field is even greater. The paper discusses the possible reasons for the discrepancies including chloride binding, specimen age, and the appropriateness of using the diffusion coefficients so determined for concrete quality control.]]></description>
      <pubDate>Thu, 14 Jan 2016 09:45:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/1394975</guid>
    </item>
    <item>
      <title>Assessment of the performance of a 24 year old coating applied to concrete bridge piers since construction in a saline tidal environment</title>
      <link>https://trid.trb.org/View/1394967</link>
      <description><![CDATA[Lynch's Bridge (inbound) over the Maribyrnong River was constructed in 1991/92, supported on six piers each of which consists of five columns and a crosshead. Two of the piers function as abutments and stand on dry land, whereas the other four piers are in the saline tidal river with a tidal range of about 0.4 to 0.7 m. The pier columns and crossheads were treated with an acrylic decorative/anticarbonation coating soon after construction in order to improve their appearance and protect them against aggressive environmental agents, including seawater and atmospheric carbon dioxide. Although the expected service life of the coating was in the order of 10 to 15 years, this coating has been in place for the past 24 years without renewal. Monitoring investigations commenced in 1999 on one pile cap and two pier columns (Pier 2 from Melbourne Abutment), and have continued since then on a regular basis in order to assess the effectiveness of the acrylic surface coating in protecting the concrete against the aggressive agents, particularly chloride ion penetration, and the consequent chloride-induced corrosion damage. The present work was carried out in line with scheduled monitoring to provide additional information on the performance of the surface coating. The corrosion activity of the reinforcement has not changed significantly in the past 15 years. The reinforcing bars in the tidal and splash zones have shown higher corrosion activity compared to the drier atmospheric zone. The chloride content at the depth of reinforcement in the column has not yet reached the corrosion initiation threshold. This may be why the corrosion rate of the steel bar in the tidal/splash zone of columns remains low. Since 1999, the chloride profile of the concrete at tidal zone has not advanced, which may be attributed to the barrier effect of the acrylic coating applied on the columns.]]></description>
      <pubDate>Thu, 14 Jan 2016 09:44:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/1394967</guid>
    </item>
    <item>
      <title>Trafiksäkerhets- och trygghetsaspekter i samspelet mellan gatumiljöns utformning och en mer energieffektiv belysning</title>
      <link>https://trid.trb.org/View/1347590</link>
      <description><![CDATA[The project's aim was to study the traffic safety aspects of new lights and the interaction with the street environment for pedestrians and cyclists. This project investigated the lighting conditions, effects on cyclists, and the interactions between lighting, traffic safety, street environmental conditions and/or other effects such as perceptions of safety for three different light sources (mercury vapour 125W, ceramic metal halide 70W and LED 25W) located in about the same type of street environment on a pedestrian and bicycle path on Kungsholms strand in Stockholm. Results show that the energy consumption of the LED lighting is 28% of the traditional mercury vapour lighting and 49% of ceramic metal halide lighting. This study shows that it is possible to obtain sufficient uniformity levels with LED lighting but that the levels are dependent on the luminaire design, pole design and the number of poles per meter road (in this study the pole spacing was 15.3 m). This study demonstrated no difference in cycle speed for LED lighting between daylight and darkness, or between different types of lighting. It worked well to perform analysis of perception of safety aspects based on simple estimates (through analysis of digital photographs). For example, perceptions of visibility corresponds very well with the measured uniformity.]]></description>
      <pubDate>Fri, 27 Mar 2015 12:06:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/1347590</guid>
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