Alkali-Silica Reaction (ASR) can cause significant damage to concrete structures including bridges, roadways, airport runways, and nuclear power plants. When reactive aggregates are included in a mix, the presence of moisture initiates a reaction between the alkaline cement paste and reactive amorphous silica. The result is a gel that continues to dilate, which may cause cracks in the concrete mass. A research program was undertaken at the University of Toronto to investigate the effects of ASR on large-scale and small-scale concrete specimens. Several specimens were constructed using reactive (ASR) concrete and non-reactive (regular) concrete, and their short-term and long-term structural and mechanical behavior were compared. In this presentation, we will discuss the results of the research program, will offer best practices to minimize the risk of ASR in concrete during placement, and will propose several strategies for repair of structures that have been degraded due to ASR.
The application of nondestructive testing and evaluation for detecting existing defects and anomalies in concrete structures will be presented. Proper inspection and assessment is an integral part of a successful repair and rehabilitation. A well-defined inspection will help asset owners and their consultants in identifying the location and extent of existing defects, and enabling them in selecting proper repair materials and optimizing the area that needs rehabilitation. Moreover, NDT methods can help identify potential defects that are not visible to the naked eye, such as early-stage delamination, corrosion, and other durability related issues. In this presentation, several cases in Canada will be demonstrated, where the results of nondestructive testing and evaluation have been used to help consultants and contractors with cost-effective and reliable repair planning. Applications of ground penetrating radar, ultrasonic pulse echo tomography, seismic tomography, will be discussed.
This exciting new publication has been sought for years, and it fills a need for a practical and current guide on evaluating, testing, and, where needed, repairing existing masonry. The book provided background, reference material, and guidance to design professionals, building owners, and contractors on existing masonry. Construction characteristics of masonry structures, typical material properties, and analytical approaches are included for historic, transitional, and modern masonry construction typologies. The main focus of the book is structural stabilization, strengthening, and retrofit with maintenance and serviceability items (such as water penetration and cleaning) addressed as subtopics.
Arrowhead Stadium originally opened in 1972 and is known to be the home to the Super Bowl Champions Kansas City Chiefs. Renovations of the stadium completed in 2010 included adding luxury suites on the club level of the stadium. This meant that the upper seating bowl not only had to seat more than 34,000 Chief fans but also act as a "roof" for the new luxury suites. The upper seating bowl comprises L-shaped precast concrete seating risers spanning from cast-in-place concrete raker beams and is divided by sixteen expansion joints. In 2018, the planning for the upper seating bowl waterproofing program began. The goal for the repair project was to implement waterproofing upgrades to protect the concrete for the next 10 years. To add to the challenge of a large-scale waterproofing and structural repair project, the construction efforts had to include coordination with simultaneous seat replacement to be completed in a single off-season.
Matching concrete sounds simple, but there are many factors that affect color, texture, and aesthetics. There is often a challenge with using modern cementitious materials for matching older and historically manufactured cements. Whether your project is historic or contemporary, this presentation will outline materials and methodology that are important to understand when concrete matching is important. With many mid-century buildings coming of repair age, this is a critical time for understanding these concepts. The presentation will include the fundamentals of concrete materials, how cementitious materials affect concrete color, how to use color measurement technology in developing a color match mix design, how aggregate exposure affects aesthetic perception, and other helpful tips when it comes to matching concrete for durable and aesthetic results. Regionally available materials will vary, but the methodology for color matching durable repairs is fundamentally the same.
This presentation aims at providing clear and down to earth definitions of what Post-Tensioning systems are, the different repair strategies related to these systems, and critical factors to be accounted for during the design and execution of any intervention on a Post-Tensioning slab.
How to properly mix, place and finish MG-Krete, a 2-component product and permanent repair material, will be demonstrated. The demonstration will show methodologies employed in horizontal, vertical, overhead and structural repairs using MG-Krete. Participants will learn the chemistry behind the product and the reason why it is a successful permanent repair material. There will be a full technical review of the product benefits.
This presentation looks at buildings that are new or being rehabilitated and the impact on making buildings more energy efficient. Starting with the 2012 IBC, and specifically the 2012 IECC portion of the building code and newer versions, the presentation will look at three aspects of the building envelope: Water Resistance, Air Leakage, and Moisture Transmission. It will then compare to identical buildings, the first built in 2000 and the second constructed in 2020. Illustrations and calculations will show how controlling air leakage can have an enormous impact on the service life of the structure, initial cost of construction, and on-going operations. Lastly, the presentation will look at how incorporating simple additions during the repair/rehabilitation process can have a positive impact on the environment as well as the building owner and the building’s constituents.
The demonstration will show the application of the Black Pearl® Waterproofing System. Unlike “weatherproofing”, a true waterproofing membrane will maintain its watertight integrity and prevent the passage of liquid under dynamic, static, continuous, or intermittent hydrostatic pressure. Black Pearl® is a true waterproofing membrane composed of two primary products: Black Pearl® Primer Adhesive and Black Pearl® Waterproofing Membrane. These components are based upon the same core formula of select, unoxidized asphalt cement base, butyl rubber, SIS, neoprene rubber, SBS, carbon black, fillers, plasticizers and curing agents. The Black Pearl® Primer Adhesive also has an aliphatic solvent that is within acceptable OSHA and EPA current regulations. Black Pearl® Waterproofing Membrane is a 55-mil woven polyester fabric impregnated with the Black Pearl® rubberized formula, providing extra tensile strength and stability.