Precast concrete products are prefabricated shapes manufactured from cast and cured cement and aggregate mixtures. They are produced in plants and factories and ready for on-site installation. Precast concrete products are made from precast concrete, typically a mixture of Portland cement and aggregate materials. Portland cement, the world’s most commonly used cement, is a hydraulic material that consists of calcium silicates and a clinker. Aggregates vary by application, but typically include sand and gravel. Precast concrete products that contain industrial wastes such as fly ash or bottom ash are also available.
Precast concrete products are made by filling reusable molds or forms that are cured in a controlled environment. Unlike standard concrete forms, which are poured and cured on-site, precast concrete products are made in a factory and transported to a construction site or lifted into place. Examples of precast concrete products include double-wall precast and reinforced concrete boxes. In Europe, double-wall precast sandwich panels are used widely in both single-family homes and apartment buildings. Reinforced concrete boxes are square or rectangular conduits that are made of concrete and reinforced with rebar or wire mesh fabric. Typically, these precast concrete products are used in subways, utility tunnels, spillways, storm drains, and sewer trunks.
There are several major categories of precast concrete products. Choices include agricultural products such as bunks, bunkers, and silos; building materials for both structural and decorative applications; vessels for the containment of hazardous materials; marine products such as floating docks, decks, and railings; and modular paving. Precast concrete products include pre-stressed concrete columns, I-beams, single tees, double tees, and wall panels. Precast concrete retaining walls are used in both commercial and residential applications, and may include products such as sea walls, mechanically stabilized earth (MSE) panels, and modular block systems.
Precast concrete products are used in sanitary and storm runoff applications, utility structures, waste and wastewater products, and transportation applications. Storm water management projects may require the use of concrete detention vaults and concrete catch basins. Utility structures include concrete transformer pads, transformer vaults, and telecommunications structures; light pole bases, meter boxes, panel boxes, and pull boxes; and both utility vaults and utility buildings. Precast concrete products for containing non-contaminating liquids include aeration systems, leaching pits, septic tanks, and water storage tanks. Precast concrete products for transportation products include Jersey barriers, tunnel segments, and sound walls or barriers.