New research is focusing on a model for calculating crack width in the case of cracks caused by progressive cooling of the wall (for example, at the stage of concrete hardening or during ambient temperature changes), the concrete shrinkage, and the subsequent service loads.
This research highlights the effect of sustained service load at elevated temperatures on the residual flexural response of reinforced concrete (RC) T-beams after being exposed to 1292°F (700°C) or 1652°F (900°C) for 3 hours, and then air cooled.
The use of recycled concrete aggregate (RCA) in concrete production can lead to a significant reduction in the Modulus of Elasticity (MOE).
A field work study of four bridges in Denver, Colorado was conducted to assess the behavior of prestressed concrete bridges carrying light rail transit loadings.
The geopolymer investigated in this research shows potential as a lightweight coarse aggregate for concrete, with the additional benefit of reducing the environmental impact of fly ash from coal-fired power generation.
A team of researchers, contractors, and state materials engineers concluded that the simple process of casting large diameter drilled shafts with a central void completely eliminated mass concrete conditions that can accompany large concrete structures .
Controlling or limiting the internal relative humidity (moisture) within concrete may prevent deterioration from occurring, or slow ongoing deterioration.
The use of recycled concrete aggregate (RCA) in new concrete production can minimize the environmental impact associated with the construction industry.
The use of discarded/rejected precast concrete represents a significant opportunity as a source for clean recycled concrete aggregates with consistent properties and high quality.
The use of mineral admixtures in concrete produced with treated recycled concrete aggregate enhances both the mechanical and durability properties leading to sustainable development.
The present study addresses the feasibility of reinforced concrete columns totally reinforced with glass fiber-reinforced polymer (GFRP) bars achieving the drift requirements specified in various codes.
Results from a recent study show that a prescriptive code-based approach can lead to critical underestimation of seismic demands.
An experimental study examines the physical characteristics of internally cured concrete using organic and inorganic materials, including chloride-related responses.
The “Engineering Ethics” webinar will review various codes of ethics and their applications, along with a review of some case studies and lessons learned.
An innovative conductive composite, ionically conductive mortar, is developed in this study.
The results described in this work show the electrical resistivity measurement method has the potential to be an accurate means for measuring the water absorption of very fine particles. Such advances in characterization methods for fine particles support the broader acceptance of recycled concrete.
Analysis to evaluate the onset of global instability under tension/compression load shows that the onset of buckling can be identified using either a proposed buckling theory or computer simulations.
Test results show that interactions between admixtures can reduce air-void stability, contributing to lowered freezing-and-thawing durability and scaling resistance.
The research outcomes reveal that stress state can markedly affect the ASR performance of concrete by affecting ASR expansion, influencing opening and orientation of ASR cracks, and associating directional effect on the mechanical properties of concrete.
New research is focusing on the use of deicing salt blends to build concrete roads that are more durable and extend the service life of concrete pavements.
With partial replacement of aggregate, it may be possible to mitigate ASR and associated damage when high cement content and potentially reactive aggregates are used.
This study shows that combining NSM-FRP flexural strengthening with U-wrap FRP shear strengthening will improve the bond without compromising on the deformability of the beam before failure.
Recognizing the need for flexibility in future construction, researchers at the University of Toronto have been working towards identifying potential benefits from combining different fibers and developing models to predict their response
This research illustrates the potential value of fiber optic distributed strain sensors for reinforced concrete research and the potential for assessing the performance of new and existing structures.
Research shows the evaluation of structural buildup at rest is essential for quality control and performance of self-consolidating concrete.
As the single most widely used construction material in the world, concrete is of substantial interest in relation to sustainable development. There are many environmental consequences induced by the consumption of raw materials but also interesting opportunities of recycling waste materials that can improve its sustainability.
The design of new structures, as well as the retrofit strategies of existing buildings, have become the preferential target of contemporary engineers and architects for achieving sustainability goals in the construction industry.
The American Concrete Institute (ACI) has released the printed and digital editions of one of its 2017 Manual of Concrete Practice.
The American Concrete Institute announces the availability of two important new documents for concrete industry professionals: ACI 301-16 Specifications for Structural Concrete, and the ACI Field Reference Manual. ACI 301-16 complements the completely reorganized ACI 318-14 Building Code Requirements for Structural Concrete
Concrete deep beams are commonly used when designing transfer girders or bridge bents. These elements are exposed to aggressive environments in northern climates, which causes the steel bars to corrode. Researchers examined the use of fiber-reinforced polymer (FRP) instead of steel as internal reinforcement in deep beams
The code requirements represent a major milestone in the industry—not only is it the first material-specific set of requirements for repair materials, but it also serves as ACI’s first code specifically for repairing reinforced concrete.
Use of Fiber-Reinforced Concrete in construction will allow for the use of less and simpler steel reinforcement while maintaining good structural behavior and potentially reducing the amount of post-earthquake repair. Such results will lead to a cheaper way to construct safe buildings with reduced life-cycle costs for the owner.
This paper describes an examination of the development of tension lap splices in high strength concrete and the applicability of the restriction in the ACI 318 code where the values of √fc’ used to calculate development length shall not exceed 100 psi.
Fire causes extensive financial losses due to property damage, as well as endangers the life and well-being of occupants. This new study throws light on the behavior of reinforced concrete members subjected to fire.
Repair of damaged bridge columns following an earthquake is a good alternative to replacement. New repair method shows benefits include cost savings, reduction in construction time, and decreased interruption of emergency services.
Student teams from around the world competed in the recent ACI Fiber-Reinforced Concrete Bowling Ball Competition. During this event, students were challenged to design and construct a fiber-reinforced concrete bowling ball that achieves optimal performance for specified tests and tasks, and document and present the team’s work to an audience of industry professionals.
New concrete pavement repair research shows that using nanomaterials can improve long-term performance and durability, and reduce life-cycle costs.
Research shows that utilizing recycled rubber derived from scrap vehicle tires can significantly contribute to the development of semi-lightweight and lightweight concrete.
University of Auckland researchers test frame components from a 20-story building damaged during the 2010-2011 Canterbury earthquakes to help engineers improve earthquake design and assessment guidelines
An innovative precast concrete (PC) T-wall panel system was developed to enhance constructability and lateral load resistance of fast-track, low-rise buildings.
This study shows that slenderness has an important influence on the punching strength of slabs with shear reinforcement, despite the fact that it is neglected in many codes of practice.
New concrete research indicates that critical crack does not develop until after the specified service load has been surpassed, suggesting that current pipe designs are overly conservative.
The ACI Excellence in Concrete Construction Awards provides a platform to recognize concrete projects at the forefront of innovation and technology, and showcases these projects to inspire excellence in concrete design and construction around the world.
Due to the environmental effects of natural sand mining, the regulations discourage the use of natural sand for concrete manufacture. Research shows using crushed sand in self-consolidating concrete is a viable alternative.
Recently, the first full-scale experiments on recycled concrete structures were made and one of the tests was rather ambitious: the structures were subjected to horizontal forces until they collapsed in order to evaluate their seismic capacity.
Research on reinforced Engineered Cementitious Composites shows that they can improve infrastructure sustainability by reducing the amount of repair and maintenance needed during the service life.
The American Concrete Institute (ACI) announced the winners of the 2015 Excellence in Concrete Construction Awards, who were honored during the ACI Awards Gala at the Concrete Convention & Exposition, November 9, 2015 in Denver, CO.
Long-term durability is a major issue for today’s infrastructure. In order to create concrete bridges with longer service lives and better performance, we must better understand the long-term behavior of these members.
Farmington Hills, MI - Every day we are impacted by recycled materials. We dry our hands with recycled paper towels, drink our coffee from recycled paper cups, and even drink our water from recycled plastic bottles. But what about building materials?
In the human body, small wounds are easily treated by the body itself, requiring no further care. For bigger wounds to be healed, the body may need outside assistance. Concrete is like a living body, in that it can self-heal its own small wounds (cracks) as an intrinsic characteristic.
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