Architectural concrete gives a structure a more aesthetically pleasing surface while also serving a structural purpose. The proportions of the mix, as well as the features and applications of architectural cast-in-place concrete, are examined.
The Carpenter Center at Harvard University, designed by Le Corbusier, was the first place where architectural concrete was used. Many designers in the United States were quite excited about this project. Between 1965 and 1990, the use of architectural concrete increased dramatically. This concept resulted in form sculpturing, new concrete mix design, higher quality form liners, and enhanced placement and consolidation techniques. Finally, improved colour and texture would be uniformly distributed throughout the structure.
Features of Architectural Concrete
Also checkArchitectural concrete is a modern solution that meets all needs, regardless of the area of interest, such as civil engineering, economic considerations, or aesthetic concerns. Architectural concrete is currently a popular design medium in architecture. It has been demonstrated that no other material can be utilised and performed in the same way. Architectural concrete will be required for all building jobs. Using fresh architectural concrete and proper formwork systems and form lining, any shape of desired quality and strength can be achieved.
Architectural Concrete is influenced by design elements. Certain factors will have an impact on the production of architectural concrete. The following are some of them: The use of formwork and a form lining system. The mixture of concrete. This will cover the cement type as well as the aggregates used. The pigment kind and quantity. The releasing agent for architectural concrete mix choosing. Sanding, cleaning, polishing, and sandblasting will be used as part of the surface treatment. Color varnishing, coatings, and hydrophobizing impregnation are examples of further operations. The use of architectural concrete will expand as concrete technology improves, allowing for the incorporation of fibres and other elements.
Considerations in Mix Design for Architectural Consideration
In order to execute effective consolidation and achieve the desired strength for the project, the architecture concrete must have adequate workability. The architect should define the design specifications that are unique to the structure being planned and built. Engineers must determine the structure’s design strength while taking into account service needs, realistic construction factors, precast works, handling, and erection work. If the concrete mix is intended solely for structural purposes, all aggregate grades must be included, resulting in a mix density that is optimal. A excellent concrete mix for the production of architectural concrete aims to achieve colour and texture homogeneity while avoiding segregation and surface defects.
When the texture of the concrete is the most important consideration, a single sieve size range of coarse aggregate combined with masonry or concrete sand in lower amounts is recommended. This mix ensures that aggregates are distributed evenly, resulting in a pleasing texture. The usage of gap graded aggregates, which exclude coarser sand particles and finer coarse aggregate particles, aids in the creation of a mix that can generate a surface devoid of insect holes. This is only possible if sufficient consolidation is done. By altering the sand content, colour variations can be achieved. The aggregate transparency is achieved through the use of darker-colored aggregates.
Architectural Cast-in-Place Concrete and its Mix
It is not necessary for architectural concrete to have a mix design that is identical to that of normal concrete. When a contractor takes an order for architectural concrete, he must guarantee that the concrete produced has appropriate strength and workability in order to provide a concrete surface with minimal flaws. This is a significant responsibility for the lead designer, and it should not be entirely borne by the contractor. A fine to coarse aggregate weight ratio of 1:2:5 to 1:3:5 is required for gap graded mixes. The most common fine aggregate is masonry sand. If the mix contains more cement, the amount of coarse graded sand is sufficient, as the cement can dissolve the sand.
However, in the case of a mix with a lower cement concentration, fine aggregate particles in the requisite amount are required to achieve adequate workability.The use of a higher cement concentration in the concrete mix will result in a high heat evolution. Thermal curing blankets can be used to protect the concrete exterior and prevent rapid cooling of the concrete, which can lead to thermal cracks. Self-consolidating concrete (SCC) is becoming more popular in concrete plants. This is also more widely used in precast building plants. When ignoring the additional requirements for quality control and materials in SCC production and concentrating on the benefits of SCC, such as:Skilled labour shortages Reduction of air bubbles Product uniformity has improved.
Mix Considerations for Smooth Textured Architectural Concrete
Air, water, cement, and fine aggregate in the proportions of 50 to 66 percent by absolute volume are required for successful consolidation of continuously graded concrete. By weight, the absolute volume will be 45 to 60 percent. If rounded aggregates are utilised, this value will be lower, and if crushed aggregates are used, this value will be greater. Fine aggregates account for around 35 to 45 percent by weight or volume of the total aggregates used in architectural concrete to achieve a smooth texture. Aggregates with a particle size smaller than 3mm must not be utilised in excess of 5%. If you limit the amount of air spaces as well as their size, you can save a lot of money.
A coarse aggregate size of 9.5mm is suitable for a very mild sandblast texture. The Indiana Limestone finish is known for its relatively light texture. Continuously graded aggregates or gap graded aggregates might be employed. Mixture for Architectural Concrete with a Medium Texture When coarse aggregates in the medium range are utilised in concrete mix, they appear to stick to the concrete surface when the cement/sand matrix is removed from exposed surfaces. Otherwise, the usage of such a diverse variety of aggregates will result in significant unevenness on the concrete’s surface. In gap-graded mixes, a maximum size of 25mm is recommended. It will be extremely difficult to insert larger aggregates. The larger aggregates will not be affected.
Mix for Heavy Texture Architectural Concrete
Aggregates with a size range of 4.75 mm to 9.5 mm must be deleted in order to obtain a heavy exposed aggregate finish. This will aid in the avoidance of concrete that is prone to segregation issues. The fine aggregate used must pass through the 2.36mm filter 100 percent of the time and the 150mm sieve 0 to 10% of the time. It’s also better to utilise industrial or masonry sand that passes a 2.36mm filter rather than regular fine aggregates. The fineness modulus of the sand used must be less than 2.4. More coarse aggregates will be used in architectural concrete with a thick texture. During the manufacturing process, these mixes must have a slump value of less than 125mm.
Cast-in-place Concrete, sometimes known as poured-in-place concrete, is a type of concrete that is poured in place, or in the finished position of a concrete component. For concrete slabs and foundations, as well as components like beams, columns, walls, and roofs, cast-in-place concrete is the best option. The concrete is usually delivered to the job site in an unhardened state, usually by a ready-mix concrete truck. The concrete is placed in the desired spot or into a dumper or pump via a chute that extends from the back of the vehicle. Precast concrete, which is prepared, cast, and cured off-site, usually in a controlled manufacturing setting, using reusable moulds, is an alternative concreting technology. See Precast concrete for further details.While cast-in-place concrete allows for more flexibility, it is not always the best option.
Normal Strength Concrete. This concrete combines all the basic ingredients — concrete
Architectural concrete refers to concrete that while providing an aesthetic finish.
A cast-in-place concrete wall system is an exposed structural system.