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How Black Concrete is Made (and its Application in 7 Projects)

How Black Concrete is Made (and its Application in 7 Projects)

As cliché as it may sound, there are two things that architects really like: exposed concrete and the color black. While concrete offers a distinctive rough aesthetic, emphasizing the tones, textures, and surfaces that shape the concrete mixture, the sobriety that the color black provides allows the architect to highlight specific characteristics precisely. Combining the two seems natural. But black pigmented concrete is not as common as we might imagine. Below we talk a little about the black concrete production process and some projects that use it.

© Giorgio Marafioti © Leonardo Finotti © Giorgio Marafioti © Giorgio Marafioti + 11

黄色视频网 - 免费午夜福利不卡片在线The concrete pigmentation process is not new. Experiments started in the 1950s, which involved nothing more than adding some type of pigment, in the form of powder or liquid, to concrete aggregates (sand and stone) when they were still dry, in an amount of 2% to 5% of the weight of the cement. The entire mixture becomes pigmented, although only a small part is visible. Specifically for black concrete, iron oxide () is generally used, found in nature as the mineral . When added to the concrete mix, the iron oxide particles encompass and coat the cement particles, which are 10 times smaller. That is why the amount of pigment is dosed based on the amount of cement, not sand, gravel, or water. [1]

© Giorgio Marafioti
© Giorgio Marafioti

There is also the possibility, although less often recommended, of using in the mixture to achieve an even darker surface. However, while iron oxide pigments bond to cement and become a permanent part of the concrete matrix, carbon black does not. When the water evaporates, it can extract the carbon, making the concrete fade more easily.

黄色视频网 - 免费午夜福利不卡片在线The pigmentation of concrete has a purely aesthetic function. Structurally, colored concrete performs similarly to conventional concrete. Academic research [2] has indicated that pigments can reduce bulk density, slightly increase water absorption capacity by 1%, and compressive strength by up to 20%. It concludes that the use of colored pigment in concrete does not negatively affect the physical and resistance characteristics of the hardened concrete.

© Giorgio Marafioti
© Giorgio Marafioti

黄色视频网 - 免费午夜福利不卡片在线The use of pigmented concrete requires a more controlled process, and ideally it should be done by specialized suppliers. Another issue to take into account is that, after the work, for any patch or maintenance to be done on the surface, care must be taken to reach the original shade. Good design documentation is essential for this. With all these considerations, the process ends up becoming a little more expensive. However, by dispensing with an especially expensive part of the work in the form of coverings, it might actually be considered an option with a good cost-benefit ratio. As a result of pigmentation, structures can become more exclusive and striking. See, below, a selection of projects that use black concrete:

Black Bridge / Ondřej Císler + Petr Tej

© Jakub Skokan e Martin Tůma / BoysPlayNice
© Jakub Skokan e Martin Tůma / BoysPlayNice

Villa Comano / Attilio Panzeri & Partners

© Alessandro Crinari
© Alessandro Crinari

Carlota Hotel / JSa

© Camila Cossío
© Camila Cossío

Casa Bruma / Fernanda Canales + Claudia Rodríguez

© Rafael Gamo
© Rafael Gamo

Panpo-ri Residence / a round architects

© Kim Joo-Young
© Kim Joo-Young

Villa Montagnola / Attilio Panzeri & Partners

© Giorgio Marafioti
© Giorgio Marafioti

The Garoa Store / Una Arquitetos

© Leonardo Finotti
© Leonardo Finotti

Notes
[1] Sullivan, Chris. The Benefits of Tried and True Iron Oxide Pigment. Concrete Decor & Professional Trade Publications Inc. Available in .
[2] Viola HOSPODAROVA, Jozef JUNAK, Nadezda STEVULOVA. Color Pigments in concrete and their properties. Article in Pollack Periodica. Available in .

About this author
Cite: Souza e Pereira, Eduardo e Matheus. "How Black Concrete is Made (and its Application in 7 Projects)" [Como é feito o Concreto Preto e sua aplicação em 7 projetos] 02 Mar 2020. ArchDaily. (Trans. Souza, Eduardo) Accessed . <http://www.bszhifu.com/934531/how-black-concrete-is-made-and-its-application-in-7-projects/> ISSN 0719-8884

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