Troy’s nephew, James graduated from the University of Louisville with a Master’s Degree in Engineering. During his studies he focused on structural engineering, graduating with Chi Epsilon honors. After graduating he soon began his own business specializing in overlaying and repairing existing concrete. His mix designs began based on DOT specifications for bridge decks. Today he combines polymers, pozzolans, fiber reinforcements, high range water reducers, and other trade secrets in all of his mix designs depending on the individual project needs.
When overlaying existing concrete bridge decks, several types of mixes can be used depending on the specific requirements and conditions. Here are some common types of mixes used for overlaying concrete bridge decks that USA Concrete Pros will often combine:
- Latex-Modified Concrete (LMC): LMC is a popular choice for bridge deck overlays due to its excellent bonding properties and durability. It consists of a mixture of Portland cement, fine aggregates, water, and a latex polymer additive. The latex polymer enhances the bond between the existing concrete and the overlay, improving resistance to cracking, shrinkage, and chemical attack.
- Polymer-Modified Concrete (PMC): PMC is similar to LMC but uses a different polymer additive. It offers improved workability, durability, and resistance to freeze-thaw cycles and chloride penetration. Polymer modifiers enhance the adhesion, strength, and flexibility of the overlay, making it an effective option for bridge deck rehabilitation.
- Fiber-Reinforced Concrete (FRC): FRC incorporates steel or synthetic fibers into the concrete mix, providing enhanced tensile strength, crack resistance, and impact resistance. It is commonly used for bridge deck overlays where high strength and improved resistance to cracking and spalling are desired.
- High-Performance Concrete (HPC): HPC is a specialized concrete mix designed to achieve superior strength, durability, and long-term performance. It often incorporates advanced admixtures, such as silica fume or fly ash, to enhance strength and reduce permeability. HPC overlays are used to rehabilitate bridge decks with high traffic loads or exposure to harsh environments.
- Self-Consolidating Concrete (SCC): SCC is a highly flowable concrete mix that can spread and fill formwork under its own weight without the need for vibration. It offers excellent consolidation, reducing the need for additional compaction. SCC overlays can improve the quality and efficiency of bridge deck rehabilitation by ensuring uniform and void-free placement.
It’s worth noting that the selection of the overlay mix depends on various factors, including the condition of the existing bridge deck, anticipated traffic loads, exposure to environmental factors, and project specifications. Consulting with structural engineers and concrete specialists is essential to determine the most appropriate mix design for a specific bridge deck overlay project.
