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Title Document type Published Publisher
TRL PPR 362 Performance of impregnants

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Since the early 1990s there has been a requirement to utilise hydrophobic pore-lining impregnants to provide additional durability on Highways Agency structures subjected to aggressive conditions – primarily arising from the use of de-icing salts. The material that has generally been used as an impregnant is monomeric alkyl (isobutyl) – trialkoxy silane. More recently alternative materials have come onto the market and the Highways Agency (HA) has updated its requirements to include new test methods to assess the effectiveness and performance of pore-lining impregnants. The purpose of these tests is to facilitate the acceptance of these alternative materials. A series of experiments was undertaken to assess the effectiveness of available impregnants for suppressing the ingress of chloride ions into concrete and their long term effectiveness in service. Laboratory tests demonstrated that the ingress of chloride ions by ponding and water uptake by sorptivity was significantly reduced by treatment with the pore-lining impregnants. By contrast, pore-blockers provided only very limited resistance to chloride ingress and virtually no resistance to water uptake. A limited number of tests were also undertaken on cores extracted from bridges.

Research 26/11/09 Transport Research Laboratory Add icon
Whole-life infrastructure asset management: good practice guide for civil infrastructure

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This good practice guide: identifies the principles of effective whole-life infrastructure asset management for long life civil engineering infrastructure assets, particularly in the transport and distribution industries describes the key steps required to successfully implement such whole life infrastructure asset management highlights existing good practice in whole life infrastructure asset management provides examples and case studies of the practical implementation of asset management. The primary audience for this guide is engineering or other technical and professional managers who are new to the principles and uses of asset management. It may also be useful to experienced asset managers who are interested in reviewing the good practice examples and case studies from UK infrastructure organisations.

Secondary Doc. 01/10/09 CIRIA Add icon
Blast Effects on Buildings (2nd edition) - Chapter 11

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"Chapter 11 - Vehicle-borne threats and the principles of hostile vehicle mitigation". Extract from "Blast effects on buildings - 2nd edition" published Thomas Telford, 2009. Provides an overview to vehicle-borne threat, practical site assessment and the principles methods for hostile vehicle mitigation.

General Information 01/06/09 CPNI Add icon
Drystone retaining walls and their modifications: condition appraisal and remedial treatment

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This publication provides infrastructure owners, consulting engineers, contractors and maintenance managers with guidance on the management, condition appraisal, maintenance and repair of drystone retaining walls. It is based on a detailed review of published literature and infrastructure owners' procedures, consultation with experts and practitioners within the field. The purpose of this publication is to present good practice, provide a guide for routine management, recommend assessment, maintenance and repair strategies to give value for money and help knowledge sharing. This publication is divided into ten chapters, each including information and guidance on particular aspects of drystone retaining walls, followed by appendices with detailed information for practitioners including case studies demonstrating good practice.

Secondary Doc. 01/03/09 CIRIA Add icon
TRL PPR 376 Bridge deck waterproofing: Non_U4 concrete finishes

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It is currently a requirement that when concrete bridge decks are re-waterproofed, repairs to the surface are needed so that the waterproofing is applied to a finish equivalent to the U4 finish defined in the Specification for Highway Works. A study has been carried out to assess whether lengthy and costly closures to make the repairs can be avoided by applying waterproofing directly to rough or damaged concrete surfaces. The most frequently occurring defects on bridge decks were identified and ranked according to their frequency, severity, difficulty to repair and cause of delays. Some defects must be repaired prior to waterproofing so the study focussed on other types. Finite element analyses determined the effect of increasing the thickness of the waterproofing membrane in large depressions. The maximum principal strains induced in surfacing overlaying a waterproofing system were calculated and fatigue lives were estimated. A laboratory investigation determined the ease of application of two spray-applied systems and a ‘pour and roll’ sheet system to concrete slabs with small depressions, small holes and ridges. The performance of the systems applied to slabs with defects and those with a U4 finish were compared. Tensile adhesion tests were carried out and the thickness of the membrane of the spray-applied systems was measured. The test results demonstrated that satisfactory waterproofing performance can be achieved by applying waterproofing to some defects, although the thickness of the membrane of the spray-applied systems was not easy to control and the defects were filled with bonding bitumen prior to the application of the sheet system. The benefits and costs of waterproofing a non-U4 finish without making repairs was assessed. The overall time savings if concrete repairs are not made before waterproofing a non-U4 finish may not be realised if other bridge works take longer than the time taken for concrete repairs to be made and cure. However, the use of rapid curing repair materials is likely to bring similar if not greater benefits than waterproofing without making repairs. A number of clauses are recommended for inclusion in the Specification for Highway Works.

Research 20/02/09 Transport Research Laboratory Add icon
TRL PPR 376 Bridge deck waterproofing: Non_U4 concrete finishes

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It is currently a requirement that when concrete bridge decks are re-waterproofed, repairs to the surface are needed so that the waterproofing is applied to a finish equivalent to the U4 finish defined in the Specification for Highway Works. A study has been carried out to assess whether lengthy and costly closures to make the repairs can be avoided by applying waterproofing directly to rough or damaged concrete surfaces. The most frequently occurring defects on bridge decks were identified and ranked according to their frequency, severity, difficulty to repair and cause of delays. Some defects must be repaired prior to waterproofing so the study focussed on other types. Finite element analyses determined the effect of increasing the thickness of the waterproofing membrane in large depressions. The maximum principal strains induced in surfacing overlaying a waterproofing system were calculated and fatigue lives were estimated. A laboratory investigation determined the ease of application of two spray-applied systems and a ‘pour and roll’ sheet system to concrete slabs with small depressions, small holes and ridges. The performance of the systems applied to slabs with defects and those with a U4 finish were compared. Tensile adhesion tests were carried out and the thickness of the membrane of the spray-applied systems was measured. The test results demonstrated that satisfactory waterproofing performance can be achieved by applying waterproofing to some defects, although the thickness of the membrane of the spray-applied systems was not easy to control and the defects were filled with bonding bitumen prior to the application of the sheet system. The benefits and costs of waterproofing a non-U4 finish without making repairs was assessed. The overall time savings if concrete repairs are not made before waterproofing a non-U4 finish may not be realised if other bridge works take longer than the time taken for concrete repairs to be made and cure. However, the use of rapid curing repair materials is likely to bring similar if not greater benefits than waterproofing without making repairs. A number of clauses are recommended for inclusion in the Specification for Highway Works.

Research 20/02/09 Transport Research Laboratory Add icon
TRL PPR 338 Automated inspection of highway structures

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The recent collapses of the I-35W Mississippi River bridge in Minneapolis, and Montreal’s Boulevard de la Concorde overpass have highlighted the importance of regular structure inspections to ensure they remain safe and fit for purpose. Currently, in the UK, highway structures are assessed using a regime of visual inspections, performed by trained engineers. These inspections are performed at four levels: Routine, General, Principal and Special. The inspections cover a range of detail, from a cursory check for gross defects, to a close examination of all surfaces of the structure, including the use of special equipment if required. The quality of data collected depends on the ability of the inspectors to observe and objectively record details of defects. It has been found that the data provided by such inspections can vary significantly. Research has been performed to investigate the use of images of the structure to assess its condition off-site. The aim is not to remove the engineer from the inspection process but to assist them and make their job easier. The research has concentrated on two main areas: image collection, and image analysis. The image collection work has investigated the practical issues involved in imaging structures. Such issues include image resolution, lighting, removal of parallax, location referencing of individual images and the development of a prototype collection system. This prototype system makes use of distance measurement lasers and theodolites to determine the position of each image on the structure, and relative to any other image, making it easy to know precisely which parts of the structure are affected by any particular defect. The image analysis work has attempted to segment the images so that the defects or features present on the structure can be highlighted and classified. The segmentation work has made use of a number of image processing techniques including wavelet analysis and has achieved promising results to date. Processing work has begun to classify the segmented objects into those which should be present on the structure (cabling, drainage, lighting, etc) and those which should not be present on the structure (defects).

Research 12/12/08 Transport Research Laboratory Add icon
TRL PPR 338 Automated inspection of highway structures

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The recent collapses of the I-35W Mississippi River bridge in Minneapolis, and Montreal’s Boulevard de la Concorde overpass have highlighted the importance of regular structure inspections to ensure they remain safe and fit for purpose. Currently, in the UK, highway structures are assessed using a regime of visual inspections, performed by trained engineers. These inspections are performed at four levels: Routine, General, Principal and Special. The inspections cover a range of detail, from a cursory check for gross defects, to a close examination of all surfaces of the structure, including the use of special equipment if required. The quality of data collected depends on the ability of the inspectors to observe and objectively record details of defects. It has been found that the data provided by such inspections can vary significantly. Research has been performed to investigate the use of images of the structure to assess its condition off-site. The aim is not to remove the engineer from the inspection process but to assist them and make their job easier. The research has concentrated on two main areas: image collection, and image analysis. The image collection work has investigated the practical issues involved in imaging structures. Such issues include image resolution, lighting, removal of parallax, location referencing of individual images and the development of a prototype collection system. This prototype system makes use of distance measurement lasers and theodolites to determine the position of each image on the structure, and relative to any other image, making it easy to know precisely which parts of the structure are affected by any particular defect. The image analysis work has attempted to segment the images so that the defects or features present on the structure can be highlighted and classified. The segmentation work has made use of a number of image processing techniques including wavelet analysis and has achieved promising results to date. Processing work has begun to classify the segmented objects into those which should be present on the structure (cabling, drainage, lighting, etc) and those which should not be present on the structure (defects).

Research 12/12/08 Transport Research Laboratory Add icon
Response to a Bridge Strike over the Railway

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This protocol identifies these issues and recommends practices and procedures which will assist in rail services and road traffic being restored with suitable protection in place until the parapets can be repaired or reconstructed, thereby ensuring safety for all travellers.

Secondary Doc. 01/04/08 Department for Transport Add icon
Intelligent monitoring of concrete structures

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Management of concrete structures requires an understanding of the deterioration processes involved and the rate at which they proceed. Intelligent monitoring is automated monitoring which explicitly provides information on current condition and deterioration rates to assist in predicting the remaining life of a component or structure. Surface mounted or embedded sensors may be used to monitor various aspects of structural condition, reinforcement corrosion, and the environment in and around a concrete structure.

Secondary Doc. 01/01/08 CIRIA Add icon
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