世 外 . 陶 源 The Clay Settlement
Overview
Singapore is constantly searching for new alternative construction materials to reduce the reliance of importing from neighboring countries. It is projected that the upcoming big scale subterranean projects in Singapore will produce a large amount of excavated clay soil that has the potential to become a new construction material. Conventionally, clay is used to produce clay bricks and architectural ceramics, which are commonly used as facade treatment. The thesis seek for innovative uses of the excavated clay to create a new clay product that works beyond the conventional clay products. The new clay products are able to address Singapore's tropical climate and structurally self support. The fundamental understanding in the material is acquired through a series of theoretical research and actual experiments with clay. The technique of casting, is adapted to conduct the clay experiments. From the experiments, the achievable geometry and the extent of complexity in using clay are investigated. The results of experiment will then form the parameters for the process of designing with clay and drives the tectonic of architecture. The design process began with designing the basic unit
of architecture – a "cell", which can be duplicated to form structures. The cells have been tested with digital structural simulation to make sure the design is able to self support. The clay cells will be used to create enclosures and pavilions in the masterplan - Clay Settlement. It is situated within the new Clean Tech Park, where the last two surviving Dragon Kilns in Singapore reside. Clay Settlement is a place for public to learn and experience pottery art in a garden setting. With introduction of new programs, it preserves the historial Dragon Kilns and pottery activity which has took place at the site since 1920s.
Background: Clay as Alternative Construction Material
The Need of Alternative Construction Material
Clay as The Potential New Alternative
Construction industry in Singapore relies heavily on concrete and steel, as 90% of building construction in Singapore is concrete based.1 With no mining sources and manufacturing plants, Singapore has been relying on importing construction material, especially cement, steel and sand from neighboring countries. Sand crisis in 2007 has caused a spike of 75% in concrete price, signaling there is a need to reduce reliance on concrete and move towards more sustainable construction method.
Due to extensive underground development, Singapore produces abundant amount of excavated soil. An estimated 924, 200 m3 of soil is excavated from the construction of Circle Line Mass Rapid Transit in 2011. In the same year, 8.5 million m3 of soil were excavated to build basement car parks, shops, underground expressways, and MRT tunnels. However, the excavated soil are not utilized efficiently as statistic shown in 2011, only 50% (3.9million m3) of excavated soil were used for reclamation project in Pulau Tekong, whereas the other half was disposed at offshore dumping site at St John Island.3 In the Underground Masterplan 2019 which will be revailed by the Urban Redevelopment Authority, it is expected that there will be more underground developments in the upcoming years and the amount of excavated soil will also increase.
As Ministry of Development stated in a media release in January 2007, “…Shift towards less concrete-based construction will help advance Singapore’s construction industry towards a ‘sustainable construction’, one that adopts the greater use of more renewable materials and more environmentally friendly methods of construction”2 , there is a need to seek for a new alternative to reduce the reliance on importing.
Lee Shiuh Liang, “Tropicalizing Rammed Earth -Viability of Rammed Earth in Singapore”,National University of Singapore, 2008.
1
“Indonesian Land Sand Export Ban is Unlikely to Slow Construction Works in Singapore,” Ministry of National Development, Building and Construction Authority, accessed 18 August 2018, https://www.bca.gov.sg/Newsroom/others/pr240107. pdf
In addressing the surplus of excavated soil, the former National Development Minister Mr. Khaw Boon Wan has also called for innovative ways to turn excavated materials into useful construction material.4
“Where is Soil Excavated in Singapore Dump?” Wild Shores of Singapore, accessed 20 August 2018, http://wildshores.blogspot. com/2012/08/where-is-soil-excavated-in-singapore.html#. W8xdUUszaUk
3
2
“Khaw Boon Wan on Recycling Excavated Materials,” Chanel Newsasia, accessed 19 August 2018, https://www.channelnewsasia. com/news/singapore/khaw-boon-wan-on-recycling-excavatedmaterials-8361292
4
Site: The Last Dragon Kilns in Singapore
Dragon Kilns and Pottery Industry in Jurong Lorong Tawas, Jurong is where the last two remaining Dragon Kiln in Singapore reside. In early 20th century, Jurong is well known for its pottery and bricks industry. It is a fertile ground of clay and provides abundant amount of good quality clay for local production. Dragon Kiln, a traditional wood firing kiln, was then used by the factories to fire the clay products. Uncertain Fate of The Dragon Kilns The manufacturing based industry started to lose its significance as Singapore was transitioning to knowledge based economy after independence. In 1990s, many dragon kilns were demolished to make way for urban redevelopment, left the last two remaining dragon kilns – Thow Kwang Dragon Kiln, own by Thow Kwang Pottery Jungle and Guan Huat Kiln at Jalan Bahar Clay Studio. The Dragon Kilns are facing the uncertainy of being demolished to make way for the new Clean Tech Park, the first eco business park in Singapore which will be completed in 2030. Both Dragon Kilns are given a temporary occupation license that needs to be renewed every 3 years. Its current lease is valid till 2024. Despite that, the local potter groups are expecting a pessimistic result.
The Dragon Kiln
Originate from Chao Zhou, China, Dragon Kiln is brought by Chinese ancestors to Singapore in 1920s. Constructed of brick arches, the kiln was built climbing a 15-20 degree slope. The firebox was at the bottom and the flue at the top to encourage flow of heat through the furnace. Unfired porcelain items were placed in a kiln furniture box made of refractory clay such that ware could be stacked and placed along the whole length of the kiln.
Firing of Thow Kwang Dragon Kiln. Image credit: Screengrab of Thow Kwang Pottery Facebook Page, https://www.facebook.com/tkpotteryjungle/p
photos/a.3191414660885489/319143855421
Effort to Keep Dragon Kilns Alive Currently, Thow Kwang Pottery Jungle is serving as a cultural and educational site by providing pottery classes and giving tour to visitors i.e students and tourists. It is also collaborating with local pottery artists and promoting their artworks through their online retail platform. Thow Kwang Dragon Kiln fires two to three times per year and open for artists to fire their own pottery. Alongside with the firing of Dragon Kiln, a festival is held with bazaars, public workshop, demonstrations and tea session. On the other hand, Jalan Bahar Clay Studio provides studio space and pottery facilities for its residence artist. Guan Huat Kiln is still functional and fires occasionally by local potters group and artists.
Clean Tech One Clean Tech Two
Thow Kwang Pottery Jungle
Jurong Eco Garden Jalan Bahar Clay Studio
Clean Tech Park Boundary
Clean Tech Park (CTP) As part of Jurong Innovation District, Clean Tech Park is the first eco business park in Singapore, owned by JTC Corporation. It is an R&D and test-bedding site for early adoption of technology and solutions with prototyping labs, start up facilities, co-working spaces and residences.1 The masterplan is evolving around Jurong Eco Garden – the central green core that act as the green lung of the business park. The garden aims to protect the existing ecology and bring tropical rainforest closer to businesses. Despite the ongoing construction of CTP, JTC Clean Tech One, JTC Clean Tech Two JTC LaunchPad and Jurong Eco Garden are currently completed and open for access.
1 “Clean Tech Park,” JTC, accessed 18 August 2018, https://www.jtc. gov.sg/industrial-land-and-space/Pages/cleantech-park.aspx
Thesis Statement
Conventionally, clay is used to produce clay bricks and architectural ceramics, which are commonly used as facade treatment. The thesis seek for innovative uses of the excavated clay to create a new clay product that works beyond the existing clay products. The new clay products aimed to address Singapore's tropical climate by able to: i. control sun light ii. allow natural air ventilation iii. prevent rainwater penetration It also has to be structurally self supporting to work as a basic buiding material. The clay product will be used to create enclosures and pavilions in the masterplan - Clay Settlement - a strategy to rejuvenate the current Dragon Kiln site and preserve the historical artefact from demolition. It will be a hub for people to learn and create pottery art in a garden setting at the same time integrated with the surrounding as a green sanctuary within the eco business park.
Research: Understanding Clay
What is Clay Clay is a broad term “describing a family of naturally occurring materials that have unique composition and material properties.” 1 When it is fired, it become ceramics, a stone like material. Clay is abundantly available formed naturally over geological times through the decomposition of rocks.2 Raw clay needs to be processed before use through drying, milling, sieving and mixing.3 After the process, clay powder will then be mixed with water and other mineral substances to achieve desired workability. This mixture is known as a clay body.4 Most clay bodies for architectural ceramics are earthenware and stoneware. 5 In Singapore, there are precedents of using locally excavated soil to make durable products. Project and Facilities Management Department in National University has conducted a feasibility study of making bricks from locally sourced marine clay in 2014. The outcome has met the requirement for building bricks as stated in Singapore Standard 103:1974.6 This has proven the feasibility of using clay from excavated soil in making new architectural products.
1Martin Bechthold, Anthony Kane, Nathan King, Ceramic Material Systems, (Basel: Birkhauser) 18. 2 Ibid. 3 Daniel Rhodes, Clay and Glazes for The Potter, (Wisconsin: Krause) 1. 4 Ibid, 22. 5Martin Bechthold, Anthony Kane, Nathan King, Ceramic Material Systems In Architecture and Interior Design, (Basel: Birkhauser) 19.
Processed clay powder before mixing.
Flowchart of a modern brick and roof tile manufacturing plant. Adapted from Bender, Hadley, Hellerstein, & Hohman (2011).
Properties of Ceramics Ceramics are high in compressive strength. They seldom break under compressive loading, but usually fail from shear or tensile forces.6 Ceramics are brittle and vulnerable to crack. The process of designing with clay should avoid areas of high stress concentration, which includes drastic changes in wall thickness, sharp edges, openings, acute corners and non-filleted intersections. 7 Due to its brittle nature, forms that are too attenuated and extreme are not suitable to clay as it may collapse in the wet state during the production process before they can be finished. 8 Ceramics is also high in hardness. Unlike metals or plastics, which can be cut into complex shapes, ceramics are difficult to cut after fired. Another inherent property of clay would be its plasticity. Plasticity means when the clay body is wet with the proper amount of water, it will tend to hold any shape.9 This unique property has made possible the fabrication of the endlessly varied shapes of ceramics object. However, they are not as easy to make into complex shapes as metals or plastics.
A brick processing and manufacturing factory in Jurong, Singapore.
6 Wong Hua Lun, “Feasibility Study of Bricks from 5 Marine Clay”, National University of Singapore, 2014. 7 George Philips, A Concise Introduction to Ceramics, (Netherland: Springer) 83-84. 8 Martin Bechthold, Anthony Kane, Nathan King, Ceramic Material Systems, (Basel: Birkhauser) 22. 9 Daniel Rhodes, Clay and Glazes for the Potter, (Wisconsin: Krause) 1. 10 Ibid, 9.
Research: Industrial Production Process
Production Processes: Industrial Production Dry pressing Dry pressing is a dry process which uses powdered clay body as starting material, pressed under high, evenly distributed pressure of up to 10,000 tons in a steel mold. Traditionally, dry-pressed tiles were limited in size due to air trapped in the tile body when the powder was compressed; the pressurized air would expand and cause breakage during firing. Plastic Pressing Plastic pressing is a process often used for production of roof tiles. It is a wet process involving a doublesided mold and a clay body. Suitable for low volume production and part customization due to the use of inexpensive pressing tool. Produce high-relief parts difficult to generate with extrusion technique alone. 2
1 Martin Bechthold, Anthony Kane, Nathan King, Ceramic Material Systems, (Basel: Birkhauser) 141. 2 David W. Richerson, Modern Ceramics Engineering, (United Kingdom: Taylor and Francis) 141. 3 Ibid, 447. 4 Renzo Piano, Renzo Piano: The Complete Logbook 1966-2016, (United Kingdom: Thames & Hudson) 278. 5 David W. Richerson, Modern Ceramics Engineering, (United Kingdom: Taylor and Francis) 34.
Extrusion Extrusion is a method that has been used extensively for many years for fabrication of ceramics for parts with a constant cross section, in example tiles, sewer pipes, façade shading. Large lead screw system forces clay through a vacuum chamber and through a shaping die in a continuous fashion, resulting in linear partsthat have a consistent cross-section throughout. Sections of desired length are formed by cutting through the column with rotating knives or stiff wires.3
Central St. Giles Court, London by Renzo Piano + Fletcher Priest Architects. The facade is made up of 18 types of extruded ceramics tile designed for the project.4
Slip Casting In Solid slip casting, clay slip poured or injected into a mold and allowed to dry throughout as a solid part. Whereas for hollow slip casting, clay slip poured into a larger mold and allowed to dry out and consolidate only adjacent to the interior of mold surface. Slip casting can be used to “create extremely complex geometries through multiple parts molds (two parts are usually considered the minimum)” One limitation with slip casting processes is the long time required to cast articles in the mold. This results in a large inventory of molds, high labor and large floor space. 5
Research: Craft Based Production Process
Wheel Throwing Wheel throwing is a technique of shaping the clay by hand on a rotating potter’s wheel. It is typically used to “create rotationally symmetrical objects”1, for example vessels and requires skills. Firstly, an appropriate amount of clay body (depending on the size of final object) will be attached on the center of the bat. Before any shaping take place, the clay needs to be perfectly centered on the bat through the process of centering. Clay will be guided up into a cone shape and guided back down in a gumdrop shape until it is in the middle of the bat. Then, a potter will use his thumb to create a divot by pressing down the center of clay. The divot is further drilled until the bottom thickness reaches 6-10mm. The potter will then insert his finger into the drill hole to open the clay to a size no larger than its own diameter. Walls of the vessel will then be pulled up and shaped into desired design. Hand Building: Coiling Coiling is a method to produce clay pieces in rounder forms. Clay is rolled out in coil or ropes about 2cm thick. Coils of clay will then be placed one on top of the other clay and joined together by pulling down some of the clay from the upper coils on to the lower. This will be repeated all round on the inside and the outside of the clay piece to ensure maximum strength. This process can be repeated to achieve any geometry 1 David W. Richerson, Modern Ceramics Engineering, (United Kingdom: Taylor and Francis) 434. 2 Ibid, 1. 3 David Hamilton, The Thames and Hudson Manual of Architectural Ceramics, (London, Thames and Hudson) 25-26. 4 Ibid, 26.
as long as the form will support itself.2 To vary the diameter of the form, coils can be stacked on the outer edge of each other to widen the form, or on the inner edge to narrow it. This method and variations of it can be used to produce very large or sophisticated form. If large objects are to be made, the coils should be proportionately thicker. 3 Hand Building: Slab building/ Slabbing Slabbing is the technique which commonly used to produce angular objects, or shapes that is difficult to achieve by potter’s wheel and coiling. Clay is rolled out by hand using a rolling pin to produce a flat piece with even thickness. Clay slab is then cut to shapes suitable for the fabrication of the required form by using needle tool. Then, slabs are joined by slurry with scored cross hatching at the connection point. Several pieces of slabs are continue to assembly until the form is complete. There are two methods in slab building: stiff slab and soft slab construction. In soft slab construction, clay slab that is freshly rolled out and damp are used to form into flowing structures. Whereas stiff slab method is more appropriate for architectural and geometric forms. Before being cut and joined to create the form, the slab is allowed to dry to the leather-hard stage. 4
Research: Advance Technology Production
Addictive manufacturing technologies (AMT) or as known as 3D printing is an emerging technology for architectural application. Currently, in the context of clay-based ceramics, two AMT processes have been explored: Binder Jetting and additional AMTs through automated material extrusion. 21 Binder Jetting involves “the controlled deposition of a liquid binder solution or other material onto a bed of powder that is supplied at a controlled thickness to build layer by layer to form rigid parts.” 22 Designing ceramics part for binder jetting system should consider a few specific parameters, including minimum and maximum wall thickness, limited overall thickness variation, build volume and part dimensions, aggregate thickness of material and glaze, and feature size. Additional AMTs through automated material extrusion adapts the process of “depositing clay slips and slurries, layer by layer to realize printed ceramics elements.” 23 The process is adapted by designers to modify desktop printer to realized printed ceramics art pieces. Robotic controlled material deposition is also widely utilized in universities in prototyping architectural scale ceramics.
Research: Glazing and Firing
Glazing In industrial production process, glaze is usually applied by waterfall glaze machines that uses a continuous curtain of flowing glaze to coat the ceramics as they travel through the production facility. Automated and manual spraying method is also utilized. For artisanal effect, glaze will be applied by manual spraying or brushes and sponge. 24 Firing and Kilns Clay pieces must be fired in order to become ceramics. The chemical change that occurs during the firing of clay gives strength to ceramics. Normally, clay pieces will first undergo bisque firing to turn the fragile unfired clay into ceramics. The ceramic pieces will be fired again after glazing to fuse glaze to the surface of ceramics. In craft based setting, small electric kiln is commonly used. Whereas tunnel kilns or roller kilns are used for high-volume production, supported by automated and robotic material handling systems. 25
Experiment: Casting Moving from theoretical research, a series of experiments are carried out to understand the method of making and workability of clay. The experiments are conducted in two methods: Casting and folding. The outcome of the experiments will form the parameters as guideline for the following design process. Similar to the process of slip casting, a mixture of ceramics powder and water are poured into a mold to obtain the desired shape. The experiment first started with casting in a full mold. The product is unable to be remove from the mold. The experiment moved on to test on a preliminary design of a hollow brick and casted with 3D printed 2-parts mold. The rationale of behind the design hollow brick is to achieve environmental performance of letting lighting in and sheltering from rain. The brick can only be partially removed from the mold, as some narrow parts were stucked and broken.
PVC Multiple-parts mold made by CNC process.
Casting Process:
1. Casting after the mold is assembled.
2. Shaking to remove excessive air.
3. Lock the opening by screwing the lid.
4. Unscrew the other opening.
5. Shaking again to ensure no excess air.
6. Lock the opening and leave the cast dry.
The next experiment is using a PVC multiple-parts mold. The parts of mold are assembled by bolts and can be dismantled entirely.The experiment with was successful and it is able to reuse to reproduce samples.
Analysis From the above experiment, it can be concluded that the two factors in affecting a successful casting are: i. Design of the mold The number of removable mold parts is crucial in making a successful cast for complex geometry. Full mold and two parts mold are only allows mold to be remove in one direction. It is not suitable for complex geometry which has design at X,Y and Z dimension. A mold that can be dismantled entirely is more favorable. ii. Geometry of design As observed from experiment 2, the deep and sharp turning part of hollow bricks is unable to be demold. In experiment with multiple parts mold, the bricks need extra external force to demold the particular part. It can be concluded that design should avoid sharp corners and deep indentation which may result in breakage and failure in demolding.
Casted hollow brick.
Clay Cell Design Typology 1: D
Inspired by the story of Dragon Kiln, the cell took shape from the scales of Dragon. By exploring the cell sizes, opening angles and deppth of cell, variations are created to suit different needs of space i.e amount of light needed and privacy. The cell is also designed to be used by stacking on each another.This is to utilise the strength of clay which is good in compression.
Dragon Scale
雨 轩 Rain spout cell is designed as a rain repeling cell which will channel the rain water and prevent it from penetrating the interior space. Apart from its weather performance, rain spout cell also celebrates the beauty of rain. Rainspout allows water to flow down the screen which creates a dramatic scene. Originate from the idea of curving tiles, rain spout is made by combining curved planes. The length of spout, the size of opening and the placement of cell are explored for optimum rainrepelling performance.
Clay Cell Typology 2: The Rain
Spout
Front: combination of 5 cells with different opening sizes and porosity.
Rain water simulation
风 砖 Learning from the traditional breeze block, the new vent integrates curved surfaces within a block. Curved surface is able to help to diffuse direct light. Degrees of curvature are explored to control the amount of light entering the space, while creating dramatic light and shadow effect.
Clay Cell Typology 3: The Vent
Block
The Masterplan: Clay Settlement
A Place to Learn and Play The masterplan is a place for public to learn and experience pottery art in a garden setting. A public learning trail is introduced as the spine of the masterplan. The trail is sheltered by Dragon Pavilion - a continuous structure made by stacking of Dragon Scale Cell. Conserving Historical Clay Production Site within the new Jurong Innovation District (JID) The two historical Dragon Kilns and existing Thow Kwang Pottery Jungle are preserved in the proposed masterplan. Combining leisure, art and nature, the masterplan is a value-adding feature to JID.
The Dragon Pavilion
Sitting within the premise of Jurong Eco Garden, the Dragon Pavilion is designed as sculptural landscape element intertwining with existng landscape and framing the scenic waterfront. Designed in undulating form with distinct scale feature, the pavilion reminds the visitors of the story of dragon on site and functionally protects visitors from the sun and rain. It encompasses the entrance, the historical Dragon Kilns, outdoor pottery workshop and an amphitheatre.
Clay Amphiheatre 座台 The tail of Dragon Pavilion gentle sweeps towards the old quarry lake and forms as outdoor amphitheatre where people are invited to watch the performance, talks and demo by ceramics artist during the Ceramics Festival. On normal days, it can be a place for the visitor to rest and congregate.
卧 龙 盘 踞
Structual Simulation: Von Mises Stress (left) and Total Displacement (right).
龙 窑 重 现
Dragon Kiln 龙窑 Awaken the Dragon Kiln is the firing ceremony which will only be held for 3 times per year. Long awaited by ceramics artists and pottery enthusiasts, it is the time to fire their art work by the ancient wood firing and witness the legendary kiln to come alive again. This celebratory event is held under a pair of vaulted pavilions constructed by dragon scale bricks. The form reminiscence the arch chamber of the dragon kiln.
Structual Simulation: Von Mises Stress (left) and Total Displacement (right).
Pottery Bridge 瓦桥 Dragon Pavilion enlarges and opens up to form a pottery workshop that floats on the existing river. The pavilion frames the scenic view of the river, offering a condusive pottery learning experience surrounded by the nature.
遣 性 陶 情
Pottery Pavilion: The Rainspout
Pottery Pavilion is a working and exhibition space for ceramics artist. Made of rain spout cells, its speaks of the poetic relationship between water and the process of pottery making.
Pottery Pavilion 雨轩 The cells protect the wotking space from exposing to rain and created a dramatic scene while channeling rain water into a pool. The collected rainwater could be reused for mixing of clay and the making of ceramic pieces.
静 听 雨 落
Structual Simulation: Von Mises Stress (left) and Total Displacement (right).
Sculpture Pavilion: The Vent Block
Sculpture pavilion provides voluminous space for sculpture artist to work on and display their large piece art work. Learning from traditional breeze block, curved blocks remains its function in diffusing direct light while reinterprets the old form by introducing curve surfaces.
Sculpture Pavilion 风砖 A ramp leading to an observation platform is introduced in Sculpture Pavilion for visitors to get near to the the exhibited large piece art work.
望 瓷 风 亭
Clay Settlement 世外.陶源