What Is A Textile-Reinforced Concrete?
What Is A Textile-Reinforced Concrete?
Textile-reinforced concrete is a variant of reinforced concrete that uses textiles instead of traditional steel reinforcing bars. This method involves using a fabric cage within the concrete, instead of a metal cage.
High-tensile materials with little elongation, such as Jute, Glass Fiber, Kevlar, Polypropylene and Nylon, are reinforced using woven or non-woven fabrics. The fabrics can be woven in a spiral or layered fashion.
Materials like molten substances, ceramic clays, plastics, or concrete are then deposited on the fabric so that the inner fabric is completely covered by the concrete or plastic. This creates a concrete structure that is flexible on the inside while still having the strength provided by the outer materials.
Non-woven structures are also commonly used and special weaving machines are used to create spiral fabrics while layer fabrics are usually non-woven.
History Of Textile-Reinforced Concrete
The birth of textile-reinforced concrete (TRC) dates back to the 1980s when the Sächsisches Textiforschungs-institut e.V. STFI, a German institute focused on textile technology, began exploring the concept.
The first patent for TRC was granted in 1982 and related to transportation safety items that were to be reinforced with materials other than steel. Six years later, another patent was awarded for a safety barrier that utilized a rope-like reinforcement made from concrete waste and textiles.
The innovative arrangement and size of the reinforcing fibers, which were set in place to allow for concrete pouring, was a notable feature.
In 1996, German university students made a breakthrough by creating two concrete canoes using textile reinforcement. One canoe used alkali-resistant glass as reinforcement, manufactured using the Malimo-technique to form a continuous yarn.
The other canoe was reinforced with carbon fiber fabric. The boats competed in the 1996 Concrete Canoe Regatta in Dresden and received an award for their design, marking the first time TRC was brought to the public’s attention.
Construction Of Textile-Reinforced Concrete
TRC (Textile Reinforced Concrete) construction is based on four crucial factors: quality of concrete, the interaction between concrete and textile, the amount of fibers used, and textile arrangement inside the concrete. Concrete particle size must be selected carefully.
Coarse concrete may not permeate through textile reinforcement, so fresh concrete and chemical admixtures to enhance adhesion are ideal.
TRC is known for its thin structure, malleability, and high tensile strength due to its continuous long fiber reinforcement woven in specific directions. There are many types of yarns, textiles, and shapes used in TRC based on different strengths and properties to support correct loading.
The yarn can be made of continuous filaments or staples, and can be woven, knit, glued, braided, or left non-woven using materials like carbon, AR glass, and basalt. However, basalt loses strength in alkali solutions, so a nanocomposite polymer coating is needed. AR glass is preferred for its good adhesion and low cost despite similar issues.
TRC is a strain-hardening composite using short fiber reinforcements like carbon fiber yarn. Reinforcements and concrete matrix must be designed carefully to achieve the desired strength, and textile orientation must handle main loading and stresses.
Types of weaves for TRC fabrics include plain weave, Leno weave, warp-knitted, and 3D spacer. Permeability of the textile must be considered in the design, ensuring the open structure allows concrete flow while remaining stable. The textile must also have high tensile strength, high elongation, and higher Young’s Modulus than concrete.
TRC can be made by casting, hand lamination, or Pultrusion. In casting, formwork is built and the textile is pre-installed before concrete is poured. In hand lamination, concrete is spread and the textile is laid layer by layer until the required size is reached.
In Pultrusion, the textile is pushed through a slurry infiltration chamber and covered with concrete, then squeezed by rollers to get desired shape and size.
Uses of Textile-Reinforced Concrete
Textile-reinforced materials, such as kevlar or jute, are becoming increasingly popular in modern construction, particularly in combination with advancements in materials science and textile technology. Bridges, pillars, and road guards are being built using these materials to withstand vibrations, sudden jerks, and torsion.
The wide availability of reinforcing steel and concrete has made reinforced concrete a popular choice for the construction of buildings and bridges. However, the steel reinforcement in RC is prone to corrosion, which can lead to structural failure over time.
Textile reinforced concrete (TRC) offers several benefits over traditional RC. It is thin, cost-effective, and lightweight, making it suitable for a variety of architectural and civil engineering applications. TRC also offers better crack control than steel-reinforced concrete, as it creates multiple small cracks (50-100 nanometers wide) when it does crack.
These cracks can even self-heal, as a 50-nanometer crack is almost as impermeable as uncracked concrete. TRC can be used for full structures, like bridges and buildings, as well as for large structures in water-heavy environments like mines and boat piers.
Currently, TRC is only approved for small components such as panels, but its potential use in full structures is being explored.
TRC can also be used as a facade material, as it is thinner and lighter than typical concrete walls and a more cost-effective option than other materials. In addition, TRC can add to the strength and design of a structure when used in bridges or building profiles.
It can also be used to reinforce, repair, or add to existing structures, either for structural or cosmetic purposes. Unlike steel, TRC does not corrode and retains its strength even with small cracks, making it a great option for retrofitting old structures or adding new elements. If carbon fiber fabric is used as the textile, TRC can even be used to heat buildings as carbon fiber is conductive.
Sustainability Of Textile-Reinforced Concrete
Textile-reinforced concrete (TRC) is a lighter alternative to traditional steel-reinforced concrete. The latter is typically 100 to 300mm thick while TRC is only 50mm. This lighter structure reduces the amount of concrete needed, making it more cost-effective.
Additionally, TRC can be used to extend the life of existing structures reducing the cost of tearing them down and building new ones. It allows for repairs and extends the service life of buildings making them a more sustainable option.