Concrete is a versatile material that can be reinforced with steel to create bollards. Reinforced concrete is stronger and more resistant to impact than plain concrete, providing superior strength for the safety of pedestrians and vehicles. Bollards are available in a variety of shapes, sizes and surface finishes to suit specific needs. Some are used for traffic guidance, while others offer protection from vehicle crashes and terrorist attacks. Bollards can also be lighted for added security and visibility.
Steel bollards in bright colors line many street corners and parking lots. Sites that require a more subtle aesthetic have other options for impact protection, including precast concrete bollards. These concrete barriers are reinforced with steel for exceptional strength and come in a wide range of styles to complement any landscape or architectural design.
When compared to cast-in-place concrete projects, precast bollards typically cost less and are delivered ready for installation. They are manufactured in a controlled environment and use molds, which provides excellent quality control and predictability. They are also made in batches, allowing for a greater level of planning and scheduling. Precast concrete manufacturers also have the ability to pre-stress their products, which helps ensure they are capable of bearing heavy loads without cracking or damaging the concrete.
Precast concrete has strong compressive, but weak tension and shear strength. It is strengthened by adding steel reinforcement, which can be in the form of wire mesh or steel rebar. The steel interlocks and bonds with the concrete as it cures, increasing the strength of the concrete and the overall durability of the structure.
Many types of concrete are used to make bollards, but they can be fabricated with different aggregates, surface finishes and manufacturing methods. For example, exposed aggregate surfaces can be created with a light sandblasting that removes enough of the surface concrete to expose the unique stone material beneath. Other finishes may be as-cast, which has a smooth finish that requires no additional processing.