馬丁·勞奇訪談

馬丁·勞奇，張利

尚晉 譯

馬丁·勞奇訪談

馬丁·勞奇，張利

尚晉 譯

1 起點(diǎn)

張利：夯土幾乎是您一手在當(dāng)代建筑中打造起來的。我想這不是您第一次被問到整個(gè)夯土事業(yè)是從哪里起步的。您是在何時(shí)何地下決心將余生獻(xiàn)給夯土建筑的呢？夯土的什么品質(zhì)讓您走上了這條道路？

馬丁·勞奇：我是在福拉爾貝格的一個(gè)小村莊長大的。父親是教師、藝術(shù)家。父母擁有一座小農(nóng)場。從孩提時(shí)代起我就迷上了生土材料。我喜歡在外面玩，而大自然就是我的玩具。那時(shí)幾乎所有的村子都有自己的壤土i窯，整個(gè)社區(qū)都會(huì)從那里取壤土蓋房子或作日用。它的用途非常廣泛：從圍泉水、密封、造爐子，到家用熱敷治療。對這種材料和制作器物工藝的親身接觸讓我決定去當(dāng)造火爐的學(xué)徒，后來又到維也納藝術(shù)學(xué)院研習(xí)陶瓷藝術(shù)。在研習(xí)中我開始建造自己的柴窯，并熟悉了燒瓷所需的技巧。從這時(shí)開始我就問自己，何時(shí)何處需要加熱燒造材料？什么時(shí)候發(fā)揮原材料的優(yōu)勢更合理？最后，我創(chuàng)作出了最早的夯土畫和雕塑，并逐漸走向可居住、有供暖的房間和建筑。不過一開始顯然是藝術(shù)而非建筑的手法。

我的一些兄弟姐妹活躍在國際領(lǐng)域。在這種環(huán)境下，我的目光投向了全球生土建筑。當(dāng)然那不只是壤土屋，還有宮殿、集市、宗教場所以及完全由生土建造的城市。生土建筑能高達(dá)數(shù)層的特性令我尤為著迷。我對夯土建筑情有獨(dú)鐘，它與其他生土建筑技術(shù)相比有兩個(gè)明顯的優(yōu)勢：它能夠輕松造出承重建筑，且無需外包材料就能抵御風(fēng)雨。這就是圓滿之處。夯土建筑應(yīng)從外觀上就能識(shí)別出來。我希望這種材料以最純粹的方式表達(dá)自身。這就是與現(xiàn)代建筑相通的重要關(guān)聯(lián)。夯土建筑具有一種坦誠的結(jié)構(gòu)真實(shí)性和雄壯的美。

2 全球/本土

張利：夯土由于用了本地的土就被認(rèn)為在本質(zhì)上是本土的。但您最近采用了一種更工業(yè)化的夯土制造方法，甚至是預(yù)制。大多數(shù)人會(huì)認(rèn)為手工藝是本土的，工業(yè)的則意味著全球的。那工業(yè)化預(yù)制會(huì)危害夯土作為本土、鄉(xiāng)土材料的名聲么？

勞奇：首先這種矛盾并不真的存在。預(yù)制可以有非常本土的建造方式。比如利口樂草藥中心，加工廠離建筑場地只有3km——原材料都來自建筑半徑10km以內(nèi)的場地。目前我們正在德國有機(jī)食品生產(chǎn)商Alnatura新總部辦公樓的建筑場地直接制造。這樣預(yù)制的砌體離安裝地點(diǎn)和最終位置都不過幾米遠(yuǎn)。我們的預(yù)制工廠基本上是移動(dòng)的。對于較大的建筑項(xiàng)目，將工廠遷到建筑場地也是更經(jīng)濟(jì)、更生態(tài)的，而不應(yīng)長途運(yùn)輸預(yù)制構(gòu)件。

預(yù)制與現(xiàn)場制造是互補(bǔ)的。預(yù)制的好處在于制造不受天氣影響，并能減少現(xiàn)場施工的時(shí)間。眾所周知，今天的建筑周期越來越緊。當(dāng)然，預(yù)制也會(huì)更多地使用機(jī)器，從而提高效率。但從另一方面看，也有可能完全拋棄機(jī)器。比如，在沙特阿拉伯的阿卜杜勒阿齊茲國王世界文化中心，有時(shí)最多會(huì)需要150名工人來填充材料、制作模板和對預(yù)制構(gòu)件進(jìn)行夯筑和定位。

通過預(yù)制，夯土的應(yīng)用領(lǐng)域得到了顯著拓展。這不僅改善了前面提到的建筑周期和造價(jià)，還提高了技術(shù)可行性。如果沒有預(yù)制，我的很多項(xiàng)目是不可能完成的。

1 夯土細(xì)部/Detail of rammed earth

是在本地開采、使用壤土和生土材料，還是像很多其他產(chǎn)品一樣全球運(yùn)輸，取決于我們的選擇而不是預(yù)制的模式。是否重新尊重并欣賞人工完全取決于我們。

3 審美

張利：讓我們直面這個(gè)問題。很多人都陶醉于夯土的美。您的建筑和家用品就是有力的證明。而這種美也吸引著模仿者。最近在中國，有些建筑在嘗試用手工混凝土板模仿夯土的材質(zhì)，并得到了贊賞。您對此的看法是什么？

勞奇：我并不想評論其他項(xiàng)目或建筑技術(shù)。但我要指出夯土建筑的兩個(gè)重要方面：第一，一切要名副其實(shí)。如果混合了水泥、石灰和其他人工強(qiáng)化劑，那它就肯定不再是生土建筑了。很多好的屬性——與壤土的水溶性直接相關(guān)——在水泥和CO的使用中被削弱、甚至徹底消除了：調(diào)節(jié)濕度、易于修復(fù)、完全可回收，即材料全部回歸自然的可能性等。最近我讀到一篇關(guān)于摻土混凝土建筑的文章：“混合土經(jīng)特殊處理以避免因吸收濕氣而軟化”。這不僅以拙劣的方式掩蓋了混合物是用水泥強(qiáng)化的事實(shí)，作者還以剝奪壤土天然的優(yōu)良屬性而驕傲。我們需要理解并承認(rèn)壤土的柔軟和可溶性是它最大的優(yōu)點(diǎn)。

由于水泥的額外屬性通常是不需要的，所以就更是如此了。夯土墻能夠承受一座住宅的重量，并保護(hù)住戶免遭風(fēng)雨寒暑的環(huán)境侵襲。因此我們必須以準(zhǔn)確的名稱來表達(dá)它：假如在混合土中加入6%、8%或10%的水泥，就會(huì)得到很差的摻土混凝土，而不是天然的泥建筑。

使用水泥往往也是出于方便?；旌衔飳τ诠こ處熀凸そ掣阌谟?jì)算，而且更好處理?；旌贤翉?qiáng)化后，工人就無需深入熟悉這種材料的知識(shí)，水泥本身消除了壤土的優(yōu)缺點(diǎn)。而這喪失的是對材料和自身工藝的信任。

生土建筑的一大障礙就是易受侵蝕、變形和變質(zhì)。在我看來，這些擔(dān)心應(yīng)該加以討論，并積極面對，但其中很多問題都被夸大了。在夯土建筑上只需注意幾個(gè)施工問題：合適的基礎(chǔ)、全面的覆蓋和用水平防蝕障減緩水流。防蝕障可由陶瓦（如勞奇自宅）或粗面凝灰砂漿（如利口樂草藥中心）組成。盡管如此仍會(huì)有一定程度的侵蝕，需要從技術(shù)和設(shè)計(jì)上予以考慮。但我相信，天然的夯土墻歷經(jīng)滄桑后的風(fēng)韻美勝過許多其他建筑材料。當(dāng)表面完全磨光后，

1 How it started

ZHANG Li (LZ):You have make rammed earth what it is in contemporary architecture, almost single-handedly. I guess this is not the first time that you have been asked about how this whole rammedearth thing started.When and where did you make up your mind that you will spend the rest of your life doing rammed-earth buildings? What were the qualities of rammed-earth that moved you onto such a path?

Martin Rauch (MR):I grew up in a small village in Vorarlberg. My father was a teacher and artist. My parents owned a small farm together. Already as a child I was fascinated by earthen materials. I loved playing outside, my toys were nature and my hands. In those days, nearly all villages still had their own loam pits, from which the whole community used to draw their loam for building and daily needs. Potential uses were very broad: from encasing springs, sealing, in the construction of ovens, up to the application in home medicine for warm compresses. This personal involvement with the material and the handicraft production of things prompted me to do an apprenticeship in furnacebuilding and later to take up studies in ceramic arts at the academy of arts in Vienna. During my studies I also started building my own, wood-fired potterykilns, and realized how much energy was needed to produce ceramics. This was the start for me to ask myself, when and where it was useful and needed to fire and heat material and when it was more logical to have the raw material show its advantages? As a result, I produced the first rammed earth pictures and sculptures which gradually evolved into accessible and heatable rooms and buildings. At the beginning however it clearly was an artistic and not an architectural approach.

Some of my siblings are active in international development work. In this context my attention caught on to global earthen architecture. Of course there are not only simple loam huts, but palaces, bazaars, places of worship and entire cities built of earth. I was also especially fascinated by the fact that earthen buildings could be built several stories high. My attention was particularly drawn towards rammed earth construction which clearly has two advantages in comparison with other earthen building techniques: you can very well build loadbearing constructions and they can be exposed to weather conditions without external cladding. This is where the full circle closes. A rammed earth building should be recognized as such from the outside. I wanted the material to speak for itself in the purest way possible. This is where a very important connection to modern architecture comes in. There is a profound structural truth and great beauty in rammed earth constructions.

2 Global/Local

LZ:Rammed-earth is believed to be inherently local by the use of local soil.Yet you are recently working on a more industrialized method of making rammed-earth,even prefabs. Most people would consider hand-craft as local,and industrial means global. Is there a danger that industrialized fabrication will hurt the name of rammed-earth as a local,vernacular material?

MR:At first this contradiction doesn't really exist. In prefabrication one can build very locally. At the Ricola Kr?uterzentrum for example, the production facility was just 3 km away from the building site -the raw materials all came from sites within a 10 km radius of the finished building. At the moment we are producing directly at the building site of the new administrative head offices of the German organic-food producer Alnatura. The prefabricated blocks thus have only few meters from production site to their mounting place and final position. Our prefabrication plant is largely mobile. In the case of larger building projects it is also more economical and ecological to bring the facility to the building site, rather than transporting the pre-fab elements over long distances.

Prefabrication supplements on-site production. Prefabrication benefits consist in production being independent from weather conditions and in reducing construction time at the site. It is well-known that buildings schedules nowadays are becoming increasingly tight. Prefabrication of course, also allows a more intensive use of machinery resulting in increased efficiency. But on the other hand it also possible to cut down on machinery almost completely. At the King Abdulaziz Center for World Culture in Saudi Arabia, at times up to 150 workers were employed for the filling of material, formwork, ramming and positioning of the prefab elements.

Through the prefabrication process, the application fields of rammed earth have widened considerably. That does not only concern building schedules that can be better planned, as mentioned above, and the costs, but also technical feasibility. Many of my projects would not have been possible without prefabrication.

It depends on us and not on the prefabrication model whether we excavate and use loam and earthen material locally or send it around the globe as we do with many other products. It definitely depends on us whether we value and appreciate human labor again.

3 Aesthetics

LZ:Let's face it.There are many,many people who are lured into rammed-earth by its sheer beauty. Your buildings and domestic objects are solid evidences of that. This beauty encourages imitations. Recently in China, there are buildings trying to use hand-made concrete panels to simulate the texture of rammed-earth and have been applauded.What is your comment on it?

MR:I do not in any way want to criticize other projects or building techniques. I rather I argue for two very important aspects of building with rammed earth: first, one has to call everything by its honest and full name. If I mix in cement, lime and other artificial stabilizers then it is definitely not an earthen construction any more. Many of the positive properties - which are intrinsically linked to the water solubility of loam, are diminished through the use of cement and CO, or are lost entirely: the moisture-regulating effects, the easy reparability, the complete recyclability or rather the possibility to return the material entirely back to nature. Just recently I read an article on earthen-concrete我能一眼看到每個(gè)瑕疵。在這個(gè)意義上，壤土和夯土要柔韌得多。例如，瑞士巴塞爾的埃托沙館，在P37,圖4中可以看到它的入口。頂篷正下方有一處滲漏；因此雨水會(huì)比其他地方更容易侵蝕墻體?？蛻魧Υ速澷p有加，以至不愿翻修。成千上萬的人每年穿過這座建筑。當(dāng)然有一些更小的破損，特別是在邊角處。但它們都很難察覺。

所以我們必須消除顧慮。換言之——這是第二個(gè)關(guān)鍵點(diǎn)——我想鼓勵(lì)每一個(gè)人用無強(qiáng)化的生土進(jìn)行建造。中國有著多姿多彩的泥和夯土建筑傳統(tǒng)。在此基礎(chǔ)上，通過前面提到的施工細(xì)部改良，生土建筑在未來會(huì)有廣闊的天地。

還有兩點(diǎn)。在世界的很多地方幾乎沒有適合做混凝土的礫石，例如在整個(gè)非洲就極其稀少。這就是水泥業(yè)現(xiàn)在探索“強(qiáng)化生土建筑”的原因之一。他們一下看到了銷路更好的另一個(gè)市場——通過“壤土”“生態(tài)”和“社會(huì)”等標(biāo)簽。但建筑師也應(yīng)在初步設(shè)計(jì)階段就考慮壤土和生土等替代材料的內(nèi)在屬性和條件。鋼和混凝土建筑技術(shù)發(fā)展至今給建筑語言帶來了強(qiáng)烈的影響。那為什么生土建筑技術(shù)就不能形成相同的潮流呢？

4 土壤

張利：夯土以土壤為原材料。在中國，寸土寸金。我們不得不用上所有的土地才能供養(yǎng)龐大的人口。人們會(huì)擔(dān)心夯土建筑將奪去土地。您如何回答這個(gè)問題？

勞奇：壤土/粘土到底是什么？壤土/粘土是破碎、侵蝕、分解和沉積的巖石。水、霜、風(fēng)和構(gòu)造運(yùn)動(dòng)造成的侵蝕是構(gòu)成我們地球的決定性可持續(xù)因素。壤土淤泥、沙子、礫石和碎渣是這一過程的直接結(jié)果。這些物質(zhì)可以在全球所有的混合物中找到，而且?guī)缀跏侨≈槐M的。相反，農(nóng)業(yè)需要“腐殖質(zhì)”，即含有機(jī)養(yǎng)分的土壤。這種表土不適合夯土建筑，它需要這層肥沃的表土之下的無機(jī)沉積物。

在中國，這種侵蝕后的物質(zhì)當(dāng)然也是用之不竭的，所以絕不會(huì)與農(nóng)業(yè)用土有任何沖突。從世界上看，生土材料有近40種不同的建筑技術(shù)，都是根據(jù)各地方的壤土形成的。合適的生土類型非常廣泛。對于夯土建筑，不可用于磚或水泥業(yè)的生土和礫石類型是最合適的。

另一個(gè)非常重要的方面是無強(qiáng)化的生土建筑完全可回收。壤土、粘土和生土建筑材料可以無限次反復(fù)使用，而品質(zhì)不會(huì)降低。從這個(gè)角度看，土建筑材料是無窮無盡的。

5 成本

張利：鑒于中國的人力成本很低，混凝土是目前建筑施工成本效益最佳的選擇。夯土也需要大量人力。所以很想問問您如何比較夯土和混凝土在中國的成本。

勞奇：有一點(diǎn)，混凝土建筑材料成本效益這么好，主要是因?yàn)樗嗟脑牧虾蜕a(chǎn)它所需的能耗很便宜。但這不是關(guān)于成本的全部事實(shí)。此外，水泥業(yè)雖不需要大量工人，但在生產(chǎn)和運(yùn)輸?shù)倪^程中會(huì)釋放大量CO2。另一方面，夯土建筑技術(shù)是高度勞動(dòng)密集的。低薪水也是生土材料建筑的優(yōu)勢。倘若加上巨大的能耗以及破壞環(huán)境的實(shí)際成本，水泥和混凝土就會(huì)貴得多了。

混凝土建筑類型在過去100年中統(tǒng)治著建筑業(yè)。傳統(tǒng)生土建筑技術(shù)的發(fā)展和必要的研究全被忽視。假如只投入用在混凝土建筑技術(shù)上的一部分研究，我們就能帶來驚人的變化和生土建筑技術(shù)的革命。我們今天就會(huì)具備創(chuàng)造成本效益更高的生土建筑類型和作品的技術(shù)手段，從而以可持續(xù)的方式將生土建筑作為未來人類和環(huán)境最健康的建筑材料。尤其在中國，卓越的土建筑傳統(tǒng)在多數(shù)地區(qū)依然在延續(xù)，其潛力是巨大的。我們應(yīng)當(dāng)發(fā)揚(yáng)這一傳統(tǒng)，同時(shí)使之現(xiàn)代化。就像前面所說，我確實(shí)從中看到了創(chuàng)造高成本效益和高品質(zhì)住宅的道路。

6 挑戰(zhàn)

張利：為何生土建筑技術(shù)在建造業(yè)中仍是一個(gè)缺口？為什么沒有其他能像您這樣用生土進(jìn)行大規(guī)模建造的公司？夯土建筑更廣闊發(fā)展的最大障礙和挑戰(zhàn)是什么？

勞奇：前面已經(jīng)提到，主要的障礙之一是對水溶性的擔(dān)心。但還有其他因素。時(shí)至今日，工業(yè)化一直是影響最深遠(yuǎn)的變革之一。在鐵路和其他發(fā)明問世之前，只能就地取材。今天全球物流的能力幾乎超越了任何界限。直到今天，土建筑材料都是危機(jī)時(shí)刻或世界貧窮人口的選擇。這不僅是因?yàn)檫@種材料垂手可得，它還是一種無與倫比的、能夠自我發(fā)揮的材料。不過，數(shù)百年來這些特征被證明既是優(yōu)點(diǎn)也是缺點(diǎn)。至少在中歐就從未有過生土建筑的技術(shù)行會(huì)。當(dāng)時(shí)有木匠、磚匠、鐵匠、石匠，可從來沒有土匠。相反：權(quán)威的建筑工藝卻抵制生土建筑技術(shù)——說它是臟東西、廢物、垃圾。雖然這種材料的知識(shí)世代相傳，卻從未進(jìn)一步發(fā)展。順便提一下，這也是讓生土建筑更吸引我的地方：這種材料還有極大的發(fā)展?jié)摿Α?/p>

說到這里我要講下最后一個(gè)障礙。生土建筑是一種有挑戰(zhàn)性的非標(biāo)準(zhǔn)化建筑技術(shù)。這也讓很多人認(rèn)為生土不是一種建筑材料。我不僅把建造業(yè)的官僚泛濫視為推高造價(jià)的一大因素，更關(guān)鍵的在于它是創(chuàng)新的阻力。另一方面，夯土沒有任何建筑規(guī)范，這激發(fā)著我不斷向前進(jìn)，去面對風(fēng)險(xiǎn)，并嘗試這種材料。

如果生土建筑技術(shù)要大規(guī)模進(jìn)步，這種材料最終必須在我們培養(yǎng)建筑師和工匠的建筑學(xué)校中有一席之地。理解這種材料的人更勇于接受創(chuàng)新的風(fēng)險(xiǎn)。

或許中國具備絕無僅有的機(jī)遇，能夠繼承豐富的生土建筑傳統(tǒng)，并用屬于自己的生土創(chuàng)造出在技術(shù)和建筑上都具有高品質(zhì)的生土建筑。

還有一點(diǎn)我認(rèn)為很重要的是，大量施工公司和工匠要走出來，承認(rèn)生土建筑技術(shù)的經(jīng)濟(jì)前景，并通過創(chuàng)造生土建筑樹立全新的形象。同時(shí)需要建立相應(yīng)的框架條件，實(shí)現(xiàn)可持續(xù)的經(jīng)濟(jì)發(fā)展。

7 技術(shù)

張利：您從非洲和歐洲的工作中積累了諸多夯土技術(shù)經(jīng)驗(yàn)。您認(rèn)為中國是否蘊(yùn)藏著不為人知的夯土技術(shù)？如果有，最可能是在哪些方面？

勞奇：在中國，和全世界一樣，人們都有生土建筑的經(jīng)驗(yàn)，并仍在實(shí)踐。當(dāng)然，我也看到了這種技術(shù)寶藏，尤其是在中國。對于生土技術(shù)和添加的人造材料已有很多討論，但很少談?wù)撊劳梁蜕敛牧媳旧怼；旌贤帘旧硎嵌喾N多樣的，而這是一大優(yōu)點(diǎn)。最重要的是，生土建筑藝術(shù)以這種材料的知識(shí)和屬性為基礎(chǔ)，并熟悉它的特性，知道如何在建筑中充分利用。在我們這個(gè)以數(shù)字支配的世界中，通常要依靠大量精細(xì)的試驗(yàn)——找到精確的參數(shù)并規(guī)定下來。不過這永遠(yuǎn)也比不上材料的屬性和多樣性。人要通過觸摸感受這種材料，去嘗試它，并開拓實(shí)踐。這絕不是可以從書本中學(xué)到的東西，也不可能寫成書就一勞永逸。我們需要去嘗試各種生土材料，從實(shí)踐中學(xué)習(xí)，接受并探索，與創(chuàng)新和新方法一同進(jìn)步。

正如前面談到的，中國的過去和現(xiàn)在都有大量生土建筑。人們這種傳統(tǒng)的、內(nèi)源而直觀的知識(shí)需要發(fā)掘和傳承?！?/p>

編注/Editor's Note

i 指壤土顆粒組成中粘粒、粉粒、沙粒含量適中的土壤。質(zhì)地介于粘土和砂土之間。其成因請見本文問題4/Loam is soil composed mostly of sand, silt, and a smaller amount of clay. See Q4 for detail.construction: "… the earthen mixture was especially treated to prevent it from softening through soaking moisture". Not only is this an inapt way to try to hide the fact that the mixture was stabilized by cement, but the author is indeed proud of depriving the loam of one of its substantial positive properties. We need to understand and recognize that the softness and solubility of loam is ultimately its greatest virtue.

Particularly so, as the additional properties of the cement are often not needed. A rammed earth wall can bear the weight of a home and can shelter its inhabitants from the environmental impacts like rain, cold and heat. Hence one must call the topic by its proper name: if you add 6, 8 or even 10% of cement to an earthen mixture, you get a poor earthconcrete and not a natural mud construction.

Often the use of cement also comes for the sake of convenience. The mixture becomes more calculable for the engineer and the craftsman and is easier to handle. By stabilizing the earth mixture the workers don't need to get acquainted so deeply with the knowledge of the material, the cement as it were, levels out the positive and negative properties of the loam. What is simply missing here is the trust in the material and one's own craftsmanship.

A big impediment to earthen construction is the fear of erosion, fear of alteration and quality loss. It's important to me to make these fears subject of a discussion and to confront them actively. Much of these is exaggerated. In rammed earth building only a few constructional precautions need to be observed: proper foundations, a thorough top coverage and a slight deceleration of the water flow through horizontal erosion barriers. These barriers can consist in fired tiles (e.g. at the House Rauch), or in trasslime mortar (e.g. the Ricola Kr?uterzentrum). However there will still be a certain level of erosion which needs to be taken into account both in technically and with respect to design. I am convinced however, that a natural rammed earth wall ages a lot more dignified and with a lot more beauty than many other building materials. With surfaces trimmed to perfection, I can see every fault immediately. Loam and rammed earth is in this sense much more pliable. For example at the Etosha House in the Zoo Basel, in Switzerland. In the fig.4 on page 37 you can see the entrance, where there was a leakage directly underneath the coverage; therefore the rainwater could erode the wall somewhat more than the rest. The client appreciated it so much, that he didn't want to have it refurbished. Many tens of thousands people move through this building every year. Of course there are some smaller damages, especially on edges. But also those are hardly noticeable.

So we must relieve the anxieties. With other words - and this is the second crucial point - I want to encourage everyone to build with non-stabilized earth. In China there is a rich mud and rammed earth building tradition. On the basis of this, and improved by the constructive details mentioned above, earthen buildings have a great chance in the future.

2 位于奧地利施林斯的工作室/Studio of Lehm Ton Erde Baukunst GmbH, Schlins, Austria

Two short additional remark. In many regionsof the world there is hardly any or very little gravel suitable for making concrete. In the whole of Africa for example, it is very scarce. This is one of the reasons why the cement industry is currently discovering "stabilized earthen construction". They simply see another sales market in which they can sell even better - through labels like "loam" "ecological" and "social". But also architects should consider alternative materials like loam and earth with their inherent specifications and conditions, already in the preliminary design stage. The development of steel and concrete building techniques have strongly influenced architectural language up until today. Why shouldn't a similar trend not be possible for earthen building techniques?

4 Soil

LZ:Rammed-earth uses soil as raw materials. In China,soil is a valued commodity. We have to make use of almost all the available soil to feed our huge population.People may question that rammed-earth buildings would compete with agriculture for soil.

What is your answer to such a question?

MR:What actually is loam/clay? Loam/clay is fractured, eroded, decomposed and sedimentated rock. Erosion through water, frost, wind and tectonic earth movement is the determinant element that forms our earth sustainably and decisively. Loam silt, sand, gravel and debris are direct consequences of this process. These materials are found in all kinds of compositions all over the globe and in near endless quantities. In contrast, agriculture needs "humus", that is soil which is enhanced by organic nutrients. This topsoil is not suitable for rammed earth constructions. It needs the inorganic sediments underneath this fertile topsoil.

Also in China, this eroded material is surely available in such incredible quantity that there will never be any competition with agricultural uses. Worldwide, there are nearly 40 different building techniques with earthen materials, which have developed according to respective local loamoccurrences. The spectrum of suitable earth types is very broad. For rammed earth constructions, especially those types of earth and gravel types are best suited that can't be used in the brick or cement industry.

3 天然土壤/The soil from nature

Another very important aspect is the uncompromising recyclability of non-stabilized earth constructions. The building materials of loam, clay and earth can be reused endless times without quality losses. From that angle, earthen building materials are infinite.

5 Cost

LZ:Given the low human labor cost in China,concrete is currently the most costeffective for building construction. Rammed-earth also involves a lot of human labor. So it might be interesting to ask your perspective of cost comparison between rammed-earth and concrete in China.

4 夯土混合物/Rammed earth mixture（1,3-4 圖片來源/Copyright: Ricola AG，攝影/Photos: Markus Bühler-Rasom）

MR:Not least, concrete building material is so cost-effective mainly because the raw resources for cement and the energy needed for its production are so cheap. But this does not tell the cost-truth entirely. In addition, the cement industry does notentirely. In addition, the cement industry does not require a lot of work force but emits vast amounts of CO2in the production process and transportation. On the other side, the rammed earth building technique is very labor intensive. Low wages also profits building with earthen materials. Would there be true-cost pricing for the vast energy consumption and the environmental consequential damages, cement and concrete would need to be a lot more expensive.

The triumph of concrete building types has dominated the building industry in the last 100 years. The enhancement of traditional earthen building techniques and the necessary research involved was completely neglected. Would we only invest a fraction of the research put into concrete building techniques, we could create incredible change and revolutionize earthen building techniques. We would possess the technological means today for creating much more cost-effective earthen building types and constructions in order to sustainably establish earthen architecture as the healthiest building material for the future of man and environment. Especially in China, with its profound earthen building tradition still present in a lot of its regions, there is an enormous potential. It is important to build on this tradition and at the same time modernize it. As said before, I do see here a crucial solution approach for creating costeffective and high-quality housing.

6 Challenges

LZ:How is it that earthen building techniques are still a niche in the construction sector? Why are there no other companies like yours that can build with earth in a larger scale? What are the biggest obstacles and challenges for a broader development of building with rammed earth?

MR:As mentioned already, one of the major obstacles are concerns about water-solubility. But there are other factors as well. Until today, industrialization has been one of the most farreaching changes. Before the advent of railways and many other inventions, it was necessary to make do with what was available locally. Today's global logistic possibilities have hardly any boundaries. Up until today, earthen building materials were and are used in times of crisis or by the poorer parts of world population. This is not only due to the fact that the material that is freely available. It is also a material which lends itself to do-it-yourself construction like no other. However, over the centuries these aspects have proved not only advantageous but also disadvantageous. At least in central Europe there was never a craftsmanship guild developed around earthen construction. There were carpenters, bricklayers, blacksmiths, masons, but never any earth-builders. On the contrary: the established building crafts fought against earthen building techniques - calling it filth, muck and grime. Though the knowledge of the material was passed on from one generation to the next it was never being further developed. By the way, this is something which makes earthen architecture even more appealing to me: there is still so much development potential in the material.

With that I'll come to the last hurdle. Building with earth is defiantly a widely un-standardized building technique. This also keeps many from considering earth as a building material. Not only do I generally perceive the exuberant bureaucratization in the construction industry as a major cost driver, but above all, also as a potential preventor of innovation. On the other hand, the fact that rammed earth is not subject to any building norms gave me with stimulus and chances to always go a step further, take risks and try out the material.

If earthen building techniques are to be further developed on a grand scale, the material must eventually find its place in our schools for construction where architects and craftsmen are taught and trained. For those who understand the material, are more likely prepared to take a certain risk for innovation.

Perhaps there is a chance in China - like nowhere else - to link up with its rich earthen building tradition and pound out of its own earth both technically and architecturally profoundly high-quality earthen buildings.

What I consider also very important is that construction companies and craftsmen in sizable numbers step up and recognize their economic future in earthen building techniques and by realizing earthen buildings implement a completely new image. In parallel, respective framework conditions need to be created that allow sustainable economic development.

7 Know-how

LZ:You gained most of your expertise with rammed-earth through working in Africa and Europe. do you think there is some hidden knowhow in doing rammed-earth in China? If so,what are the mostly likely aspects?

MR:In China, as all over the world - people have built with earth and still do. As a matter of course I also see a great treasure of know-how particularly in China. We have spoken a lot about techniques and artificial materials sometimes added, but hardly about the material of loam and earth itself. Earthen mixtures themselves are varied and this is good. Above all, the art of earthen buildings rests with the knowledge of the material and its properties, recognizing its specific qualities and realizing how best to use and implement it in a building. In our world which is dictated by figures, we often rely on doing extensive and elaborate lab testssetting narrow parameters and codifying them. This however will never match up to the material properties and diversities. One has to haptically feel the material, work with it, and practically try it out. This will never be something you can learn from just reading nor can it be written down once and for all. We need to work with earthen materials, learn by doing, recognize and discover, and progress with new innovations and solutions.

As said before - in China, there was and is much earthen architecture. This traditional, partly endogenous and intuitive knowledge of the people needs to be tapped into and utilized.□

Interview with Martin Rauch

Martin Rauch, ZHANG Li

Translated by SHANG Jin

馬丁·勞奇，壤土-粘土-泥土建筑藝術(shù)股份有限公司張利，清華大學(xué)建筑學(xué)院/《世界建筑》

2016-12-08