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.
Due to concrete’s versatile nature, it is able to be used to multiple situations, performing 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.
Concrete changes volume when it dries out, this is because of its chemical compound. It cracks due to tensile stress, which is when the concrete expands. The pressure that builds up as a result of this change in volume can cause the concrete to move outward and inwards.
Measures are implemented to reduce the concrete’s ability to crack, such as putting in joints to allow for neat, straight line cracks. These joints also allow the concrete to move when its volume is changed due to expansion and shrinkage. One of the biggest factors that affect concrete is the weather. The risk of cracking is much higher on warm, dry days with low humidity and strong wind.
Metro Mix gives you the ability to design your own custom exposed aggregate mixes, with aggregates of your choice, you also have the choice to change the colour of the cement base. The only part you need to worry about is finding the perfect match, and you can leave the technical stuff to us.
Options available to you:
• A choice from Melbourne’s largest range of exposed aggregate concrete mixes on display at Metro Mix’s showroom
• The large range of aggregates (stone) available to create your custom mix
• The option to alter the colour of the cement base using quality oxide products
Polishing concrete involves grinding concrete that has been treated with a chemical desnifier that removes blemishes, and increases density. Polishing the concrete with specialised tools, fitted with diamond padding, then smooths out any peaks and valleys that may be showing. This then exposes the aggregate that has been added to the mix, creating a flat and shined surface. The resulting texture is called: Polished Concrete. There are quite a few choices of polished concrete finishes e.g. Hiperfloor, full grind and seal, light grinds (to achieve a hit and miss with the exposure of the aggregates, usually referred to as salt & pepper), natural concrete finishes and more. There is also a range of different sealers e.g. high gloss and satin (low sheen). Each different choice of finish is carried out in a similar but has slight changes in the process.
There are many benefits from polishing concrete besides a great looking floor.
• Polished concrete makes use of the materials already present, eliminating the need to install extra floor coverings such as floorboards and carpet
• Polished concrete is low maintenance, and is far more durable than any other flooring applications which means less maintenance
• Companied with special sealers provided by Metro Mix, polished concrete can be virtually impenetrable making it easy to clean and keeps it looking great
• Concrete’s chemical compound reduces dust mite and allergen problems, as well preventing any mould growth
After the concrete has been placed, a surface retarder is then applied to delay the top layer of cement from setting. This gives the concreter the flexibility to remove the excess concrete and expose the decorative aggregates (stone) that was used in the mix.
The retarder is applied once the concrete has been screed and finished and has reached a certain point of the curing stage. This prevents just the top layer of the concrete from setting, which then can be removed in a number of ways, often using a pressure cleaner.