Kris Kohl -Iowa State University Extension Field Agricultural Engineer
Concrete is a composite material made from a mixture of cement, water, sand, and aggregates such as gravel or crushed stone. Once mixed, the material undergoes a chemical reaction known as hydration, causing it to harden and gain strength over time. The result is a material that can withstand significant pressure or compression forces, it is renowned for its strength, durability, and versatility.

However, concrete is relatively weak in tension, meaning it has a tendency to crack when stretched or pulled. To counter this, reinforcing steel or fiberglass is embedded within the concrete. Reinforcing rebar, is typically made from carbon steel or fiberglass and comes in the form of rods and bars. These elements are placed strategically within the concrete to provide tensile strength, allowing the composite material to perform better under both compressive and tensile forces. This process allows concrete to be better suited for a wide range of construction applications especially in agriculture.

Benefits of Reinforced Concrete

1. Enhanced Strength and Durability: The combination of concrete and steel increases the overall strength of the structure, allowing it to withstand heavier loads and resist cracking, bending, or breaking over time. The reinforcement ensures that the concrete can handle both compressive and tensile forces, which is critical for the long-term durability of the structure.
2. Cost-Effective: While the initial material cost of reinforced concrete may be higher than unreinforced concrete, the long-term benefits far outweigh this. Reinforced concrete structures require less maintenance and have a longer lifespan, which makes them more cost-effective in the long run.
3. Versatility: Reinforced concrete is incredibly versatile and can be molded into various shapes and sizes.
4. Resilience to Environmental Stress: Reinforced concrete structures are resistant to various environmental factors such as moisture, extreme temperatures, and chemical attacks, making it a preferred material for infrastructure projects in harsh environments.

Why Consider Fiberglass Rebar
Fiberglass rebar, also known as glass fiber reinforced polymer (GFRP) rebar, is a non-metallic reinforcement material used in concrete construction as an alternative to traditional steel rebar. Made from glass fibers embedded in a polymer resin matrix, fiberglass rebar offers several advantages over steel rebar, especially in applications where traditional steel reinforcement may have limitations.

One of the most significant advantages of fiberglass rebar is its corrosion resistance. Unlike steel rebar, which is susceptible to rust and degradation when exposed to moisture, salts, or chemicals, fiberglass rebar will not corrode. This makes it an ideal choice for environments where traditional steel reinforcement would deteriorate quickly, such as coastal areas with high salt exposure, or in structures that are exposed to chemicals or high moisture levels (e.g., sewage treatment plants, bridges, or marine applications). The corrosion resistance of fiberglass rebar significantly extends the lifespan of reinforced concrete structures. Livestock structures where manure or driveways where salt is used are very corrosive environments where the fiberglass has the advantage over steel.
Fiberglass rebar is much lighter than steel rebar, often by up to 75%. Despite its lower weight, fiberglass rebar still maintains an impressive strength-to-weight ratio. This makes it easier to handle, transport, and install, leading to cost savings in terms of labor and logistics. The reduced weight also means that workers can handle longer lengths of rebar without requiring heavy equipment or cranes, reducing the risk of workplace injuries and speeding up the construction process.
Fiberglass rebar is highly durable and resistant to environmental stresses that can degrade steel rebar. It is not affected by environmental factors like humidity, UV radiation, or extreme temperatures. Unlike steel, which can expand, contract, or weaken over time due to exposure to moisture or chemicals, fiberglass rebar maintains its strength and form, ensuring longer-lasting structural integrity. This durability is particularly important in harsh climates, where materials face rapid degradation.
Fiberglass rebar is resistant to a wide range of chemical attacks. In environments where concrete structures are exposed to aggressive chemicals like acids, alkalis, or sulfates which are found in manure, fiberglass rebar will not degrade or weaken. Steel rebar, on the other hand, can corrode when exposed to these chemicals, leading to structural failure and costly repairs. One of the common issues with steel-reinforced concrete is spalling—the process by which the concrete surface breaks or chips away as a result of corrosion in the steel rebar. When steel rebar corrodes, it expands, putting pressure on the surrounding concrete and causing it to crack and spall. Since fiberglass rebar does not corrode, it eliminates this issue, leading to better long-term performance and reduced maintenance costs.
Fiberglass rebar’s resistance to corrosion and its high tensile strength help reduce the likelihood of concrete cracking over time. Steel rebar often causes cracking due to its susceptibility to rust, which leads to expansive forces within the concrete. Fiberglass rebar’s non-corrosive nature and lightweight design minimize these expansive forces, reducing the risk of cracking and increasing the overall structural integrity of the concrete.
Reinforced concrete is used in virtually every type of construction. Its applications include foundations, bridges, highways, tunnels, dams, and skyscrapers. In fact, most modern buildings, including residential homes, commercial buildings, and even large public structures, rely on reinforced concrete for structural integrity. Additionally, it’s used in precast concrete components like beams, slabs, and panels, which are manufactured off-site and then assembled at the construction site.
Since fiberglass rebar does not rust, there is no unsightly corrosion staining on the surface of the concrete. This is particularly beneficial in visible architectural projects where aesthetics matter, such as in decorative concrete, facades, or sculptures. The ability to maintain a clean, uniform appearance over time makes fiberglass rebar an attractive option for high-end construction.