Research Terms
Engineering Concrete Structures
Keywords
Concrete Durability Concrete Materials Science Concrete Microstructure Concrete Repair
PCI Concrete Materials Technology Committee, Chairperson; 2016 - present
Precast/Prestressed Concrete Institute, Member; 2014 - present
American Concrete Institute, Member; 2003 - present
This concrete formulation and or cementitious coating contains boron to protect against radiation-induced volumetric expansion. Many facilities use concrete to shield against radiation, such as nuclear power plants or radiological medical facilities. The global nuclear power plant and equipment market is projected to reach $4.9 billion by 2025. Concrete is prone to degradation in certain environments, a result of chemical reactions between alkalis and other materials in the concrete mixture. Some concrete formulations use boron aggregates to make concrete structures resistant to radiation, but the inherently uneven aggregate dispersion leaves surfaces exposed and the structure susceptible to radiation-induced volumetric expansion (RIVE), which may lead to further degradation due to alkali silica reactivity (ASR) of aggregates that are otherwise non-reactive.
Researchers at the University of Florida have developed a formulation for concrete or concrete coatings to help prevent degradation due to radiation. The formulation utilizes boron compounds that decay into lithium, which can suppress the expansive chemical reactions that cause degradation.
Boron-containing compounds in concrete and cementitious coatings to protect against radiation damage and increase concrete’s durability and service-life
Concrete formulations often use lithium salts to reduce the potential for alkali silica reactivity degradation and boron aggregates to provide neutron shielding. This formulation includes boron-containing compounds, such as fine powders, liquid solutions, or liquid suspensions, in the mixture of cementitious materials. When exposed to neutron radiation, the boron transforms in situ through radioactive decay into lithium. The formulation also contains hydrogenous compounds to aid in providing shielding from thermal neutrons as well as the thermalization of fast neutrons for additional shielding benefits. This protects the radiation-damaged aggregates and prevents alkali-silica reactions due to radiation-induced volumetric expansion. A shielding coating for concrete using this formulation can be applied directly to a surface prepared for bonding or mechanically as pre-formed panels that secure onto an existing structure. The protective coating can be applied in just days, reducing facility downtime and installation costs while allowing for regular inspection and replacement.
This magnetic inductive sensing device confirms that reinforcement in concrete structures is aligned correctly to prevent catastrophic failure. The electromagnetic system detects the density and orientation of metallic fibers in Ultra-High-Performance Concrete (UHPC) as well as rebar and other ferromagnetic substance in concrete. Civil engineering projects, new buildings, and pre-fabricated structures increasingly use UHPC due to its strength, but it suffers from inconsistent distribution of the metal fibers in it. The collapse of the Surfside condominium in South Florida in 2021 highlights the need for a better system for inspecting concrete structures. With the global construction industry expected to reach USD $16.6 trillion by 2025, it is increasingly important to evaluate the safety of structures.
Researchers at the University of Florida have developed a device that uses magnetic inductance to detect whether the metal fibers are clumped together or evenly distributed, aiding in quality control inspections of ultra-high performance concrete and other concrete. This work enables construction and inspection companies to monitor the quality of their UHPC slabs or prefabs on site.
Quality control and inspection of UHPC and other concrete structures such as bridges, parking garages, buildings, and more
This technology uses an inductive sensor to characterize the density and orientation of ferromagnetic materials in ultra-high-performance concrete. It works by magnetic induction, where a changing magnetic field causes an electric current in the material being studied, and the changing electric current causes another magnetic field in turn. The sensor is connected to a data acquisition device which records the location of each area of strong magnetic inductance.
This manufacturing process takes municipal solid waste bottom ash to produce autoclaved aerated concrete (AAC) sustainably and efficiently. ACC is a lightweight, precast, ecofriendly, and thermally insulated building material. In 2023, the autoclaved aerated concrete (AAC) market size was estimated at USD 15.50 billion and is expected to grow at a compound annual growth rate (CAGR) of 6.0% between 2024 and 2030. The growth of the AAC market is driven by the increasing demand for sustainable and energy-efficient building materials. The market value is in the building and construction industry, in addition, it offers sustainability value in the waste-to-energy industry.
Florida has the most MSWI facilities of any state in the U.S., with most plants commissioned since the early 1990s. These facilities represent 15 to 25% of MSW waste management in Florida, in areas with higher populations. This results in the production of approximately 1 million tons per year of ash residue across 12 facilities in Florida. It is important to identify ways to mitigate the negative health and environmental effects of bottom ash. Currently, the only AAC manufacturing facility using bottom ash in the United States is in Florida.
Traditional AAC production uses aluminum powder as its major aerating component. However, it must be imported from other countries, such as Mexico and Europe, incurring significant costs and reducing the viability of the AAC production. The demand for AAC in the U.S. is outpacing supply and production capacity. However, this technology provides an alternative for aluminum powder obtained from bottom ash following waste incineration.
Researchers at the University of Florida researchers employed bottom ash from municipal waste incineration to produce autoclaved aerated concrete. This provides an alternative source for aluminum powder, helping produce more sustainableand thermally efficient AAC in the United States. It also eliminates the need and cost of importing aluminum powder for AAC production. In addition, it repurposes bottom ash from waste incineration that would otherwise be landfilled, converting waste into a beneficial construction material. Thus, supporting environmental sustainability by finding productive uses for waste byproducts.
Produces autoclaved aerated concrete (AAC) using bottom ash from municipal solid waste incineration as an aerating agent, replacing imported aluminum powder
This autoclaved aerated concrete production offers a sustainable option in the building and construction industry. It uses bottom ash, containing aluminum byproduct, from municipal waste as an aerating agent. This enables aeration in the AAC while eliminating the need to import aluminum and overall reducing the cost of production.
