Concrete

Concrete is a composite material composed of water, coarse granular material (the fine and coarse aggregate or filler) embedded in a hard matrix of material (the cement or binder) that fills the space among the aggregate particles and glues them together. Concrete is cheap to produce, easily molded into various shapes, and very strong. Like stone, it absorbs and releases heat slowly and is often used in areas for passive solar heat loss and gain.

The many attributes of concrete are functions of the basic mix. Sand, water, gravel, and Portland cement are combined to achieve different densities, weights, performance characteristics, and appearances. Some environmentalists suggest using fly ash, a by-product of coal-powered factories, instead of Portland cement to reduce carbon dioxide emissions.

Concrete is fireproof and virtually indestructible when properly fabricated. Although cold and hard, it is naturally moisture and insect resistant. If not sealed properly, it can stain easily, but otherwise requires little or no maintenance.

Concrete can be laid on-site and is also available precast into slabs, blocks, tiles, and thin wall panels. Lighter concrete blocks have a better insulation quality than heavier blocks, and newer, translucent concrete allows light into otherwise dark interiors.

Concrete should be mixed by professionals, and protective clothing should always be worn when working around fresh concrete as it can burn the skin if splashed. Concrete must cure fully before it can be used and should be treated if exposed to prevent it from continually shedding or breaking down into fine particles.

The vast majority of concrete used in residential construction is cast on the site where the final product will be used. For new construction, the need for a spacious area in which to fabricate the concrete, move it to the site of the pour, and let it cure for up to four weeks is not a problem. When the material is to be used in an existing interior, the challenge of where and how to mix, move, and pour the material is exacerbated by close-in walls and existing finishes that need protection.

Concrete can be transformed into a structural material by pouring it over steel rods, wire, or mesh. It is used extensively for foundations and structural supports. Although concrete sets in hours, it takes up to a month to cure properly, and some areas might have to be out of bounds for a time. The temperatures in these areas must be stable and well over freezing at all times in the curing process. Concrete will not set if mixed on or near the freezing point.

Concrete can be colored by adding pigments to the base mix as it is manufactured. It also stains easily. Mixing cement with water causes a chemical reaction and the wet concrete, if splashed onto the skin, can burn. Concrete is used to create foundations and smooth sub-floors for heavier materials such as stone and ceramic and can be used as the finished flooring, as well. Poured with mixed-in color and a smooth finish surface, concrete creates warm and interesting flooring. Concrete is suitable for an under-floor-heating element.

Concrete can be poured into molds and allowed to set. The molds, usually wooden or possibly metal, support the concrete while it sets and is then removed. Various patterns, shapes, and textures can be worked into the mold to create an imprint on the finished item. Concrete is used for countertops, floors, sinks, tubs, tables, and work surfaces.

Types of cement concrete

• Waterproofing cement concrete
• Coloured concrete
• Light weight concrete
• No fines concrete
• Pre cast concrete
• Ready mix concrete
• Transit mix concrete