Heydar Aliyev Centre / Zaha Hadid Architects. Image © Iwan Baan

What is the Future of Concrete in Architecture?

由专筑网小R编译

混凝土是世界上应用第二广泛的材料，同时也是二氧化碳的排放元凶之一，混凝土制造行业在每年的碳排放总量中所占比例为5%至7%。混凝土这种材料在建筑行业中十分流行，但是结合环境的不稳定性，混凝土成为了研究人士的创新对象，全球各地的设计师、建筑师、研究者都在为混凝土的未来前景而进行着构思。

Concrete is the second-most used material on earth. It is also the second-largest emitter of CO2, with cement manufacturing accounting for 5 to 7 percent of annual emissions. The continued popularity of concrete as a material of choice in the design and construction industry, coupled with increasing unease of the environmental consequences, has put concrete firmly in the spotlight of innovation and experimentation. As a result, designers, architects, and researchers around the world are generating multiple visions for what the future of concrete in architecture could look like.


TAKTL's ultra-high-performance concrete panels on the Waikiki Business Plaza by MGA Architecture. Image © TAKTL

数千年来，混凝土一直是建筑师和施工者的首选材料，其最早的使用甚至可以追溯到公元前6000年的叙利亚与约旦，混凝土有着成本低、功能多、应用快等特点，人们也对其较为熟悉，大约每年的混凝土浇筑量为220亿吨。BBC的一项研究表明，自从1950年之后，混凝土的产量增长了30倍，而自从1990年之后，这个数值又增长了4倍，部分原因则来源于欧洲战后的建筑发展热潮，以及上世纪90年代之后亚洲的建筑发展。根据专业人士预测，到了2030年，混凝土的产量也许会增加25%。

Concrete has been a material of choice for architects and builders for thousands of years, with the earliest known use dating from Syria and Jordan in 6000BC. Its low cost, versatility, fast application, and sheer familiarity to those involved in using it means that roughly 22 billion tons of concrete are poured every year. According to a recent BBC study, production of cement has increased thirtyfold since 1950, and a further fourfold since 1990, driven in part by postwar building in Europe, and building booms across Asia from the 1990s onwards. It is predicted that to keep pace with demands in South East Asia and sub-Saharan Africa, cement production may have to increase by 25% by 2030.


ETC Zurich's 3D printed columns. Image © Benjamin Hofer

人们愈发对建筑环境对于气候的影响产生重视，而混凝土所承担的压力也愈来愈大，BBC的Lucy Rodgers认为，“如果混凝土工业是一个国家，那么它将会成为仅次于中国和美国的第三大排放国。相较于航空燃料，混凝土能够产生大约多2.5%的二氧化碳，甚至不少于全球的农业事业（12%）。”在波兰举办的2018年COP24气候变化大会里，有人强调如果要做到2015年巴黎气候协议，那么到了2030年，混凝土的二氧化碳排放量必须下降16%。那么在这样的前提下，建筑师和研究者则需要思考的是，如何让混凝土拥有绿色的施工建造过程。

With renewed scrutiny of the contribution of the built environment to climate change, concrete has sustained particular pressure. According to Lucy Rodgers at BBC News, “if the cement industry were a country, it would be the third-largest emitter in the world – behind China and the US. It contributes more CO2 than aviation fuel (2.5%), and is not far behind the global agriculture business (12%).” At the UN 2018 COP24 Climate Change Conference in Poland, it was highlighted that in order to meet the requirements of the 2015 Paris Climate Agreement, annual cement emissions must fall by 16% by 2030. Against this backdrop, architects and researchers have generated a bounty of possibilities for how concrete might evolve for a greener construction process.


“KnitCandela" by Zaha Hadid Architects. Image© Juan Pablo Allegre via ZHA

这些创新大部分都集中在减少混凝土混合物中的水泥含量上，近期，MIT研究社公布了一种混凝土制造策略，这种策略能够减少二氧化碳的排放。研究人员利用电化学方法，这种方法能够在二氧化碳释放之前就将其捕获，同时研究人员也建议在燃料和水工业中应用分离碳。

另外还有一个创新思维是将生物基础材料和元素整合到混凝土混合物中。近期，英国兰开斯特大学的研究人员公布了一种方法，这种方法能够从胡萝卜和根茎类蔬菜中提取纳米元素来促进混凝土的混合，而由Sandra Manso-Blanco博士开发的“生物感知混凝土”则是另一个趋势，这种技术能够见证结构混凝土的分层，然后促进苔藓和地衣植物的生长，这些植物能够有效地吸收混凝土。

Many of these innovations focus on the reduction of cement in concrete mixtures. Recently, MIT researchers revealed an experimental method of manufacturing cement while eliminating CO2 emissions. Using an electrochemical method that captures CO2 before it is released, the team proposes using the sequestered carbon in the fuel and drinks industry.
A related stem of innovation comes from integrating bio-based materials and elements into concrete mixtures. Recently, researchers at Lancaster University in the UK unveiled a novel approach of using nanoplatelets extracted from carrots and root vegetables to enhance concrete mixes. Another trend of “bioreceptive concrete”, developed by Dr. Sandra Manso-Blanco, sees structural concrete layered with materials to encourage the growth of CO2-absorbing moss and lichen.


Glass Fiber Reinforced Concrete. Image © Samuel McGuire

另一种已经应用在建筑之中的混合物是GFRC，即玻璃纤维混凝土，这种材料由混凝土、沙子、耐碱玻璃纤维、水组合而成，这种玻璃纤维混凝土的主要特征是具有一定的塑形，它能够构成又薄又轻的外部墙板，扎哈建筑事务所设计的阿利耶夫中心的外部也应用了这种材料，同时高迪的圣家教堂也结合了玻璃纤维混凝土。

An alternative mixture which is already entering mainstream architecture is GFRC (Glass Fiber Reinforced Concrete). The material consists of a mortar made of concrete, sand, alkali-resistant glass fiber and water. Plasticity is one of the main qualities of GFRC, enabling the molding of thinner and thus lighter façade pieces. For example, this material is used in the cladding of the Heydar Aliyev Centre by Zaha Hadid Architects, and it is also being used to implement the complex forms of Gaudi’s Church of the Sagrada Familia.


Heydar Aliyev Centre / Zaha Hadid Architects. Image © Hélène Binet

扎哈建筑事务所除了在施工过程中应用了玻璃纤维混凝土之外，建筑师们还展示了一种更加新颖的混凝土应用策略，即墨西哥城艺术博物馆的3D编织贝壳，KnitCandela通过创新的混凝土贝壳结构技术，表达了对西班牙籍墨西哥建筑师兼工程师Felix Candela的敬意，该技术结合了创新的KnitCrete框架技术，而这也构成了扎哈在拉丁美洲的首个展览。电缆网和织物模板系统的编织时间大约为36小时，这也使得自由混凝土表面能够在不需要模具的前提下构成具有表现力的形式。苏黎世联邦理工大学的研究者开发了针织物件，装运在两个箱子中从墨西哥运往瑞士，其长度一共为350 公里，重25公斤。展馆的面积大约为50平方米，其轻薄的双曲混凝土外壳总重量只有5吨。

在扎哈的展览中，苏黎世理工大学的KnitCrete技术起到了重要的作用，该技术在混凝土创新发展历程中也名列前茅。苏黎世理工大学建筑学的研究者们希望能够最大化地利用空间，避免建筑成本的增加，因此设计了厚度为2厘米的混凝土面板，不仅满足承重的需求，同时满足可持续的发展目的。相较于传统的混凝土楼板，这些面板构成拱形，用于承担主要的荷载，这也让人们联想起哥特教堂中的拱形天花板，因此在不需要钢筋的前提下，二氧化碳的产生会更小一些，而厚度为2厘米的面板也比普通混凝土面板的重量要减轻70%。

As well as embracing GFRC in the construction process, Zaha Hadid Architects has also exhibited a more novel approach to concrete, having unveiled a 3D-knitted shell at the Museo Universitario Arte Contemporaneo in Mexico City. Forming part of ZHA’s first exhibition in Latin America, KnitCandela “pays homage to the Spanish-Mexican architect and engineer Felix Candela” by reimagining his inventive concrete shell structures through an innovative KnitCrete formwork technology. With a knitting time of 36 hours, the cable-net and fabric formwork system allows for expressive, freeform concrete surfaces to be constructed without the need for molds. The knitted fabric for KnitCandela, developed at ETH Zurich, was transported from Mexico to Switzerland in two checked suitcases, totaling 350 kilometers of yarn weighing 25 kilograms. The pavilion’s thin, double-curved concrete shells hence weigh only 5 tonnes in total, despite a surface area of 50 square meters.
While playing a crucial role in the KnitCrete technology between ZHA’s exhibition, ETH Zurich has been at the forefront of a number of innovations concerning concrete. With the intention of maximizing available space and avoiding steep construction costs, researchers from ETH Zurich’s Department of Architecture have devised a concrete floor slab that with a thickness of a mere 2cm, remains load-bearing and simultaneously sustainable. As opposed to traditional concrete floors that are evidently flat, these slabs are designed to arch in order to support major loads, reminiscent of the vaulted ceilings found in Gothic cathedrals. Without the need for steel reinforcing and with less concrete, the production of CO2 is minimized and the resulting 2cm floors are 70% lighter than their typical concrete counterparts.


Gothic Construction Techniques Inspire ETH Zurich's Lightweight Concrete Floor Slabs . Image via Block Research Group

近期，该机构还展示了3D打印混凝土的发展潜力，瑞士Riom的“Concrete Choreography”装置展示了第一个3D打印混凝土舞台，其中包含有无模板支柱。该装置由瑞士Riom的Origen Festival合作完成，有着9根高度为2.7米的支柱，这些支柱通过定制的软件来进行设计，并应用苏黎世理工学院开发的机器3D打印过程进行制作。打印出的空心混凝土结构使得材料的策略性更强，同时也满足了混凝土建筑的可持续发展。另外，经过计算设计的材料装饰和表面肌理都展示了3D混凝土打印技术在大型建筑中的多功能特征和美学潜力。

明显的是，混凝土是设计行业的热门材料，它有着很大的发展潜力。长久以来，这种材料为人们带来了城市的发展，同时也满足了快速的发展需求。那么现在人们应该多多考虑混凝土等材料的创新新能。建筑师所面临的挑战是通过这些创新策略，从根本上改变人们对于混凝土的使用方式，以及让全新的混凝土性能为保守的传统思维所接纳，否则，在全新的未来，混凝土很有可能为其他的材料所替代。

More recently, the institution has also showcased the potential of 3D printed concrete. The “Concrete Choreography” installation at Riom, Switzerland, presented the first robotically 3D printed concrete stage, consisting of columns fabricated without formwork. In collaboration with the Origen Festival in Riom, Switzerland, the installation features nine 2.7-meter-tall columns, individually designed with custom software and fabricated with a new robotic 3D printing process developed by ETH Zurich with the support of NCCR DFAB. The hollow concrete structures are printed to allow materials to be strategically used, allowing for a more sustainable approach to concrete architecture. In addition, the computationally-designed material ornament and surface texture exemplify the versatility and significant aesthetic potential 3D concrete printing holds when used in large scale structures.
It is clear, therefore, that there are numerous potential futures for concrete to continue as a material of choice in the design and construction industry. Having shaped our cities for centuries, and facilitating rapid expansions and new heights, it is now time to consider how materials such as concrete can continue to support innovation, by being the subject of innovation themselves. The challenge for architects will be to ensure that such innovative solutions, with the potential to fundamentally change how we do or do not use concrete, begins to become accepted in a traditionally conservative industry. Otherwise, it is clear that the environmental impact of concrete as it is currently constituted will see the material overtaken by its green competitors.