As a construction technique, spraying concrete or ‘shotcrete’ as it is now called goes back over a century, to a Chicago taxidermist who needed to devise an innovative technique for repairing the dilapidated façade of the Field Columbian Museum in Chicago. Carl Akely patented his process and the equipment it required.
Akely’s process involved spraying from a dry mixed hopper of concrete using a nozzle which introduced water to the mix at the point of departure from the nozzle.
This technique is still used, and is known as “shotcrete – dry mix”, to distinguish it from a later process which sprays ready-mixed wet concrete known as “shotcrete – wet mix”. Each has its advantages, but both require skilled operators.
The advantages of the wet mix technique include its ability to deliver larger volumes in a short space of time, and a cleaner, less dusty and less wasteful work space. The dry mix technique, by contrast, has the advantage that the amount of water in the shotcrete mix can be adjusted in real time, allowing a skilled operator to achieve optimum results, and making it easier to work overhead and vertical surfaces.
Shotcrete is a useful application for creating embankments and structures such as swimming pools, retaining walls in basements and capping beams.
Metro Mix brings the advantages of shotcrete to Melbourne homeowners, builders and architects. Contact Metro Mix for your shotcrete needs on 1300 METROMIX.
Due to concrete’s versatile nature, it can be used in multiple situations and perform various jobs. Buildings, bridges, slabs, piping, inside and outside flooring, streets, driveways, are some instances where concrete may be applied. For more decorative touches, colouring, sealing, and finishing can be applied to exposed or polished concrete, perfect for creating a custom look for homes, or businesses.
Cement is a type of binder, a substance that sets and hardens when added with water, or any other inert durable materials like stone and sand. Its chemical compound allows it to set as hard as rock and can withstand impacts, heat, abrasion, and weathering. Cement is primarily made by heating limestone to very high temperatures to create a material called clinker. The clinker is then ground with a small amount of gypsum into a powder to make ‘Portland Cement’, the most commonly used type of cement. Portland cement is a basic ingredient of concrete, mortar and most non-specialty grout. The most common use for Portland cement is in the production of concrete.
Concrete and cement are usually contrasted together as being similar products. However, cement is actually an ingredient of concrete. Cement is an additive that provides the basis for the glue that holds concrete together. Concrete is a mixture of aggregates (stones) and sand, along with water and cement. The process of mixing these materials is called hydration, where the cement and a portion of water undergo a chemical reaction and harden. This means that concrete “sets” or “hardens” as a result of the chemical reaction – and does not simply dry out. Other special additives can then be added to alter texture, pigmentation, and other properties.
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