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The cement sheath in thermal recovery oil wells is subjected to elevated temperatures up to about 320°C during the injection of steam to stimulate high viscosity crude oil production. Initially the cement sheath in these wells is pre-cured at formation temperature (=40°C) prior to being exposed to steam treatment. Steam treatment can be performed anytime from immediately after the cement has set to years later. It is generally assumed that the cement chemistry and microstructure resulting on steam injection is similar to that obtained for geothermal cements where the cement sheath is heated directly to elevated temperatures as it is pumped downhole and cured at those temperatures. The objective of this study was to determine the impact of steam treatment on the microstructure and chemistry of pre-cured cement pastes., 13th International Congress on the Chemistry of Cement: 03 July 2011, Madrid

The hydration of calcium silicate phases (i.e. C3S and b-C2S) in Portland cement results in the formation of calcium silicate hydrate (C-S-H) ? a major contributor to the strength and durability of hardened cement paste. The stoichiometry of C-S-H (e.g. C/S and H/S ratio) can vary depending on various parameters such as the initial water/cement ratio and the use of supplementary cementitious materials. The change in the composition of C-S-H has been shown to be related to its mechanical and chemical behavior. A method for modifying the nanostructure of hydrating cement systems that employs synthetic C-S-H as a nucleation seeding agent during the hydration process was developed., 13th International Congress on the Chemistry of Cement: 03 July 2011, Madrid, Spain

Aussi disponible en français: Évaluation des panneaux porteurs isolés pour évaluer leur conformité au Code national du bâtiment

Also available in English: Evaluation of structural insulated panels for National Building Code compliance

Aussi disponible en français: Évaluation d'un nouvel ajout cimentaire pour le béton

Canadian Standards Association A3000 (Cementitious Materials Compendium). Technical Committee: 29 April 2010, Niagara-on-the-Lake

Derivative conduction calorimetry is a new approach to the analysis of conduction calorimetry data. It is particularly useful in circumstances where multiple reactions take place during a single chemical process. This paper describes the methodology used for derivative conduction calorimetry. Examples of its use are given based on ordinary Portland cement hydration reactions, the hydration reactions of cement constituents and the effects of supplementary cementing materials and polycarboxalyte admixtures on those reactions. The benefits of Derivative Conduction Calorimetry are described and recommendations for its use are presented., 12th International Congress on the Chemistry of Cement, 7 July 2007, Montreal, QC.

Scandem 2007, the 58th Annual Meeting of the Nordic Microscopy Society: 18 June 2007, Espoo, Finland

This paper discusses the use of the cold field emission scanning electron microscope (CFE-SEM) for tricalcium silicate and ordinary Portland cement microscopy, with an emphasis on both the early stages of cement hydration and unhydrated samples. The recent discovery of nanoscale structures formed at the end of the induction period is described. CFE-SEMs are capable of operating at very low accelerating voltages and can thus produce very high magnification images without requiring coating of samples., 29th International Cement Microscopy Association Conference, 21 May 2007, Québec City

Carbon nanotubes (CNT) have unique mechanical properties that make them close to ideal reinforcing materials. Single walled CNT have a modulus of elasticity of approximately 1 TPa, yield strengths measured at between 20 and 60 GPa, and measured elastic strains at yield that are greater than 10%. In addition, CNT typically have aspect ratios of 1000 or more.These attractive properties have led to considerable research on CNT composites. While particular attention has been paid to polymer based materials, metal and ceramic matrix materials have also been described in the literature. A new area of research involves CNT/cement systems. Early results investigating the microstructure of these systems show promise for the eventual development of carbon nanotube/cement composites. Scanning electron microscopy at the National Research Council has observed crack bridging and fiber pull-out in CNT/cement composites. Evidence for bonding between CNT and the cement matrix has also been observed. These reinforcing mechanisms have been shown to produce higher microhardness measurements at early stages of sample hydration as compared to cement control samples without CNT. This paper describes current developments in the production of CNT-cement composites. Possible applications for a successful composite material and areas of potential structural research activity are also discussed., 3rd International Conference on Construction Materials: Performance, Innovation and Structural Implications, August 21, 2005, Vancouver, B.C., Canada

Carbon nanotubes (CNT) are the subject of one of the most important areas of research in nanotechnology. Their unique properties and potential for valuable commercial applications ranging from electronics to chemical process control have meant that an enormous amount of effort has been undertaken on the investigation of nanotubes in the last five years. Despite this high level of research activity, very little attention has been paid to potential applications in the construction industry. This paper seeks to bridge the gap between CNT and construction materials research. It describes carbon nanotubes, including their structure, how they are produced and their properties. Potential applications, both in general and specifically for the construction industry, are presented. The paper concludes by giving the results of initial research at the National Research Council's Institute for Research in Construction on carbon nanotube/cement composites., The 1st International Symposium on Nanotechnology in Construction, 22 June 2003, Paisley, Scotland

Circumferential cracking (Figure 1) may be responsible for up to 80% of the failures in small diameter (, 2002 AWWA Infrastructure Conference: 10 March 2002, Chicago, IL

2002 AWWA Infrastructure Conference: 10 March 2002, Chicago

The architecture-engineering-construction (AEC) industry is very information intensive. During a typical construction project very large amounts of information such as drawings, specifications, requests for information, and change orders flow between the different parties to the project. Managing this information is often difficult. Adversarial relationships, liability issues and the amplified economic cycles in the AEC industry have driven a separation of design and construction responsibilities and have produced specialization into small firms with narrow expertise. This has led to a level of contractual fragmentation that is unparalleled in any other industry. This contractual fragmentation has in turn led to: (a) a large number of legal entities involved in any major construction project, (b) inefficient management processes among project participants to accommodate legal constraints, and (c) re-interpretation and re-entry of information by each project participant. The result, relative to other sectors of the economy, is significant duplication of effort and introduction of errors.

Failures in cast iron water mains are more complex and diverse than is widely understood in the industry. This paper discusses the modes and causes of pipe failures that have been encountered during a three year investigation by the National Research Council Canada. In addition to corrosion, manufacturing defects, human error and unexpected levels of pipe loading all play a role in the large number of pipe failures that occur each year., Underground Infrastructure Research: Municipal, Industrial and Environmental Applications, Proceedings of the International Conference on Underground Infrastructure Research: 10 June 2001, Kitchener, Ontario

Fire detection and its corresponding safety systems are crucial parts of an intelligent building. This paper reviews the current state of development of fire detection and alarm systems in the intelligent building. New technologies and concepts developed in intelligent buildings, such as advanced multi-function sensors, computer vision systems and wireless sensors, real-time control via the Internet, and integrated building service systems, have also been reviewed and discussed. These new technologies and concepts will improve the capability of fire detection systems to discriminate between fire and non-fire threats andwill increase the time available for property and life protection. However, much effort is still needed to remove barriers to the further development of these new technologies., 12th International Conference on Automatic Fire Detection: 26 March 2001, Gaithersburg, MD., U.S.A.

Pipe failures are a common problem for all water utilities. This paper describes a step by step approach for determining the causes of those failures. This process is particularly important for investigating failures in important pipelines where the failure may have had significant social or economic costs. The steps presented include actions that should be taken to prepare for a failure analysis, work that should be done during the repair of the failed pipe and the failure analysis itself. These steps are intended to provide suggestions for water utilities and their consultants in dealing with failures of gray cast iron pipe, not as prescriptive guidelines., 2001 American Water Works Association Infrastructure Conference: 11 March 2001, Orlando, Florida

The decision to repair, renew, or replace existing old grey cast iron mains is typically based on performance indicators such as structural integrity, hydraulic efficiency, system reliability, and water quality. Structural integrity (often quantified as the number of main breaks per kilometre or mile per year) is the most common performance indicator. However, these indicators represent past performance, rather than expected future performance. Decisions based on performance indicators may not, therefore, accurately meet the real needs of the utility owner of the water distribution system. A preferred approach to make decisions on pipe repair and replacement is to determine the expected remaining service (residual) life of each pipe segment and ensure that the necessary work is performed before failure occurs. Past efforts to estimate remaining service life of water mains have been based on corrosion pit depth and estimated corrosion rate with no regard to the influence of corrosion on the structural resistance capacity of water mains. This paper describes a methodology to estimate the remaining service life of grey cast iron mains that takes corrosion pit induced changes in the structural resistance capacity into account. The methodology combines the residual resistance capacity of grey cast iron mains, anticipated corrosion rates, and the measurement of corrosion pits by direct inspection or non-destructive evaluation technology to predict when the factor of safety of an individual pipe segment will fall below a minimum acceptable value set by the utility owner, i.e., remaining service life. The estimate of remaining service life may then be used to schedule appropriate maintenance or replacement of grey cast iron mains.

The water industry faces unique problems in operating its pipeline systems. In most branches of engineering, a single structural failure is a matter for grave concern. In a water distribution system, such problems are a matter of course, with some larger cities experiencing 300 or more failures a year of small diameter (150-300 mm) mains. Water utilities simply attempt to manage the damage in order to minimize their total costs, rather than trying to prevent the damage entirely.

Recent developments in the field of diagnostic techniques for water distribution and transmission systems have given water utilities new options for inspecting and assessing the condition of their pipelines. These new techniques include the remote field effect for inspecting both metallic and prestressed concrete pipes, refinements to leak detection systems for inspecting plastic and large diameter pipes, and impact echo, spectral analysis of surface wave and acoustic emission monitoring systems for the inspection or monitoring of prestressed concrete pipes. These techniques can provide specific information on the condition of the pipes and may indicate the depth of corrosion pits in a cast iron pipe, the number of wires broken in a prestressed concrete pipe or the precise location of leaks in a plastic pipe. However, the best uses of the data from the new techniques are not necessarily clear. While the presence of a leak would normally call for repairs, the appropriate action to deal with a corrosion pit of a specific depth or aparticular number of broken wires depends on many factors, including the size and type of the pipe, past break histories, surrounding environmental conditions and the way in which the pipe is likely to fail. This paper gives an overview of an approach to using diagnostic and other information tools for maintaining pipeline integrity. The key components to the approach will be presented. Some of these components include knowledge of the failure mechanisms for the various pipe materials, the diagnostic techniques themselves, methods for estimating the likelihood of pipe failure, and techniques for prioritising pipereplacements or repairs. Areas where further research is needed will be indicated and the implications of the approach for pipeline management will be discussed., AWWA Infrastructure Conference and Exhibition: 12 March 2000, Baltimore, Maryland

AWWA Distribution Systems Symposium: 19 September 1999, Reno, Nevada

Aussi disponible en français: Des chercheurs de l'IRC étudient la défaillance des conduites en fonte

Aussi disponible en français: La surveillance acoustique permet de détecter sur-le-champ les dé faillances dans les conduites souterraines

Aussi disponible en français: De vieux tuyaux nous livrent de nouveaux secrets

Synovial sarcoma is a tumor of mesenchymal origin that is most commonly found in the extremities in close association with tendon sheaths, joint capsules, and bursae. Smith in 1927 coined the term synovioma, 1 and Knox in 1936 suggested the name synovial sarcoma. 2 However, Stuer in 1893 is credited with the first accurate description of this neoplasm. 3 Its resemblance to normal synovium was recognized early in the literature, but its origin from synovial tissues has never been substantiated. It is reported to be the fourth most common sarcomatous tumor behind malignant fibrous histiocytoma, liposarcoma, and rhabdomyosarcoma, with an 8% to 10% incidence among all malignant tumors of soft somatic tissues. 4 Nine percent of synovial sarcomas are situated in the head and neck. There have been two reported cases of synovial sarcoma arising in the temporomandibular joint; this report describes an additional case.

Canada’s buildings, bridges, roads, rail transit, potable water systems and wastewater systems provide shelter and safe drinking water, enable transport of people and goods, and collect and treat wastewater. They provide basic and core services for Canadians and are critical to Canada’s economy and the nation’s quality of life. These buildings and core public infrastructure (B&CPI) are subject to time-varying and uncertain effects due to climate change, as well as more frequent extreme weather events, such as flooding. These climate changeinduced pressures could potentially reduce the safety, serviceability, functionality, and service life of Canada’s B&CPI. In addition, Canadian B&CPI are aging and deteriorating due to different degradation mechanisms, as well as inadequate inspection and maintenance practices – issues potentially made worse by the effects of climate change. The Climate-Resilient Buildings and Core Public Infrastructure (CRBCPI) initiative was established as a research and development partnership between the National Research Council of Canada (NRC) and Infrastructure Canada to develop new and revised codes, standards, specifications, guidelines and decision support tools to ensure that Canada’s new and existing B&CPI are more resilient to the effects of climate change and extreme weather events. Funded by Infrastructure Canada and managed by NRC, the effort brings together experts from across Canada. Initiative priority areas include buildings, bridges, roads, potable water, storm water, and wastewater systems, and rail transit guideways. The initiative addresses resilience to climate change impacts on temperature, precipitation, wind and extreme weather events, including flooding, wildfires and extreme wind, which can affect these types of B&CPI across the country.

Les bâtiments, les ponts, les routes, le transport en commun sur rail de même que les réseaux d'alimentation en eau potable et d'évacuation des eaux usées du Canada fournissent un abri et de l'eau potable, et permettent le transport des personnes et des marchandises ainsi que la collecte et le traitement des eaux usées. Ils fournissent des services de base essentiels aux Canadiens et sont d'une importance cruciale pour l'économie canadienne et la qualité de vie de la nation. Ces bâtiments et infrastructures publiques de base (BIPB) subissent des effets incertains et variables dans le temps en raison des changements climatiques, et sont soumis à des événements météorologiques extrêmes plus fréquents, comme les inondations. Ces pressions induites par les changements climatiques pourraient éventuellement réduire la sécurité, le rendement en service, la fonctionnalité et la durée de vie des BIPB du Canada. De plus, les BIPB canadiens vieillissent et se détériorent en raison de différents mécanismes de dégradation, ainsi que de pratiques inadéquates d'inspection et d'entretien – des problèmes potentiellement aggravés par les effets des changements climatiques. L'initiative Bâtiments et infrastructures publiques de base résilients aux changements climatiques (BIPBRCC) a été établie sous forme de partenariat de recherche-développement entre le Conseil national de recherches du Canada (CNRC) et Infrastructure Canada afin d'élaborer des codes, des normes, des spécifications, des lignes directrices et des outils décisionnels nouveaux et révisés pour rendre les BIPB nouveaux et existants au Canada plus résilients face aux effets des changements climatiques et des événements météorologiques extrêmes. Financée par Infrastructure Canada et gérée par le CNRC, cette initiative réunit des experts de partout au pays. Les secteurs prioritaires de l'initiative comprennent les bâtiments, les ponts, les routes, les réseaux d'eau potable, d'eaux pluviales et d'eaux usées, ainsi que les transports en commun sur rail. L'initiative porte sur la résilience face aux impacts des changements climatiques sur la température, les précipitations, le vent et les événements météorologiques extrêmes, notamment les inondations, les incendies de forêt et le vent extrême, qui peuvent affecter ces types de BIPB partout au pays.