System for the Analysis and Design for Disassembly and Recycling in the Construction Industry Dirk SCHWEDE, Elke STÖRL Institute for Lightweight Structures and Conceptual Design, University of Stuttgart, Stuttgart, Germany, dirk.schwede@ilek.uni-stuttgart.de

Objectives The global construction sector is contributing significantly to the global resource consumption. That is why the European Building Products Guideline requires since 2011 that buildings, their materials and parts of the building can be recycled. At this point in time however the design and building praxis has not nearly achieved this objective. Building structures are in general not designed and constructed for later disassembly and recycling. Whether a building can be recycled or not, does not only depend on the selection of materials, but also on the joints and connections between the material layers and the building elements. If for instance materials can be separated in specific material groups or if connected materials do not compromise each other in quality, recycling is possible. The connection technology is not considered sufficiently in many disciplines when buildings are designed and constructed. In this paper a constructive language is introduced and based on this, design methods and tools for the design are developed. The language is underlaid with databases of information on material, characteristics of joints and the compatibility of materials. The developed approach will support designers to optimize structures and building elements for deconstruction and recycling.

Objectives Tool supports the designer to assess: structure  ability to be deconstructed jointing principles  ability to be disassembled materials  recyclability (re-use, disposal) Tool supports the designer to substitute and improve: joints with low destruction potential  joints with high disassembly potential material layer compromises recyclability of adjacent layer  neutral material  joints that allow separation of the layers without contamination

Methods Evaluation of the ability to disassemble joints (DIN 8593-0, section 3, table 1): “A connection produced through a joining principle and able to be disassembled, can be undone without destruction of the fitted components.” “A connection produced through a joining principle and not able to be disassembled can only be undone with damage or destruction of the fitted components.”

Methods Evaluation of the ability to disassemble joints (DIN 8593-0, section 3, table 2): 5: best performance, 1: weakest performance 5: “able to be undone without damage of the components“ 4: “in general able to be undone without damage or destruction of the components” 3: “in general mostly only able to be undone with damage of the components” 2: “in general only able to be undone with damage or destruction of the components” 1: “only able to be undone with damage or destruction of the components”

Methods Evaluation of the ability to disassemble for each fastening principle “joining” (DIN 8580, DIN 8593-0): 4.1 Zusammensetzen 4.1.1 Auflegen, Aufsetzen, Schichten SK, FS 1 4.1.2 Einlegen, Einsetzen SK 4.1.4 Einhängen SK, FK 4.3 An- und Einpressen   4.3.1 Schrauben KS 2 4.3.4 Fügen durch Presspassung 3 4.3.5 Nageln, Verstiften, Einschlagen 4 4.4 Fügen durch Urformen 4.4.1 Ausgießen FS 4.5 Fügen durch Umformen 4.5.3 Fügen durch Nietverfahren FS 4 4.6 Fügen durch Schweißen   4.6.2 Schmelzverbindungs-schweißen SV 5 4.8 Kleben 4.8.2 Kleben mit chemisch abbindenden Klebstoffen (Reaktionsklebstoffe) AD 5.1 Beschichten 5.1.2 Anstreichen, Lackieren 5.1.4 Putzen, Verputzen

Methods Potential contamination of one matter by another matter (paint, glue, mortar, plaster, etc.) for each material combination: - material contaminates neighbouring material + material is contaminated by neighbouring material = no contamination

Methods Elements of the Recycling Graph: boxes: materials ellipses: coatings circles: joints, fastenings Types of fastening: manufacturing process according to DIN 8580, main group 4 (joining) + 5 (coating) material coating joints, fastenings type of fastening DIN 8580 potential contamination mat.1/mat.2 labelled according to DIN 8580

Results External wall with thermal insulation manufacturing techniques according to DIN 8580 composition (4.3.5 nailing, doweling, driving): non-positive connection composition (4.4.2 embedding): positive connection composition (4.8.1 gluing, physical bonding): adhesion coating (5.1.2 paining, varnishing): adhesion coating (5.2.1 filling): adhesion coating (5.3.1 plastering): adhesion wall composition (from inside to outside) – classification of materials according to ÖKOBAUDAT 1. 5.5.02 interior paint (dispersion paint) 2. 1.4.05 gypsum surfaces 3. 1.4.01/.02 concrete 4. 1.4.05 bonding mortar 5. 2.2 EPS insulation 6. 2.21.02 plastic dowel 7. 1.4.04 basecoat mortar 8. 6.6.04 reinforcement fabric (glass fibre) 9. 1.4.04 basecoat mortar 10. 5.5.01 base coat 11. 5.5.01 silicone raisin plaster

Results Insulated and ventilated outside wall with curtain brick sheeting on substructure wall composition (from inside to outside) – classification of materials according to ÖKOBAUDAT 5.5.02 interior paint (dispersion paint) 1.3.13 gypsum board Air layer, 30mm 3.1.01 wood slat 4.1.05 screw with dowel 1.4.01/.02 concrete 2.1.01 insulation layer (mineral wool) 6.4.01 thermal spacer PVC (hard) 4.3.02 aluminium wall fastener 4.3.02 vertical aluminium profile 4.3.02 aluminium profile 4.3.02 aluminium clip fastener air layer, 30mm 4.3.02 aluminium jointing profile 1.3.07 brick sheeting manufacturing techniques according to DIN 8580 composition (4.1.1 composing, layering): gravity (+friction) composition (4.1.2 inserting): gravity (+friction) composition (4.1.4 hinging): gravity, spring power composition (4.3.1 screwing): non-positive connection composition (4.4.2 embedding): positive connection coating (5.1.2 paining, varnishing): adhesion

Results Concept visualisation of the RecyclingGraph modelling tool description of the material and its ability to be recycled characteristic of the composition technique between material layers compatibility of two materials and the composition between them

Results ILEK RecyclingGraph Editor

Results External wall with thermal insulation RecyclingGraph ConnectionMatrix M1 interior paint (dispersion paint) M2 gypsum surfaces, 3mm M3 concrete, 180mm M4 bonding mortar, 5mm M5 EPS insulation, 140mm M6 basecoat mortar, 2mm M7 reinforcement fabric (glass fibre) M8 basecoat mortar, 3mm M9 basecoat M10 silicone raisin plaster, 3mm M11 reinforcement steel mesh M12 plastic dowel, 200mm, 60mm M13 EPS insulation for plastic dowel, 15mm Structural composition M2 gypsum board, 12mm M3 aluminium profile, 30mm x 50mm M4 concrete, 180mm M5 thermal spacer PVC (hard), 5mm M6 aluminium wall fastener, 120mm x 160mm M7 rivet, steel M8 vertical aluminium profile, 50mm x 50mm M9 rivet, steel M10 aluminium profile, 20mm x 50mm M11 aluminium clip fastener, 20mm x 50mm M12 brick sheeting, 390mm x 190mm M13 air layer, 30mm M14 reinforcement steel mesh M15 insulation layer (mineral wool), 140mm M16 air layer, 30mm M17 screw, steel M18 dowel, plastic M19 dowel, plastic M20 screw, steel M21 aluminium jointing profile, 30mm x 60mm Insulated and ventilated outside wall with curtain brick sheeting on a substructure

Results Insulated an ventilated two-shelled brickwork outside wall RecyclingGraph ConnectionMatrix M1 interior paint (dispersion paint) M2 interior plaster, lime cement, 15mm M3 vertically perforated brick, 373x175x238mm M4 insulation layer (mineral wool), 140mm M5 wind barrier, PE, vapour permeable M6 air layer, 40mm M7 clinker brick, 240x115x71mm M8 mortar, d=12mm M9 wall tie, l=340mm, 4mm M10 mortar, d=12mm M11 clamping disk (fastening of insulation), 50mm Structural composition Insulated and ventilated outside wooden post-and-beam wall M2 gypsum board, 12,5mm M3 gypsum board, 12,5mm M4 wood slat, 100mm M5 oriented strand board, 18mm M6 screw, steel M7 wood slat, 180mm M8 screw, steel M9 wood slat, 100mm M10 staples, steel M11 PP non-woven fabric , sealant M12 wood slat, 50mm M13 screw, steel M14 lumber, larch, 25mm M15 insulation layer (mineral wool), 100mm M16 insulation layer (mineral wool), 180mm M17 insulation layer (mineral wool), 100mm M18 air layer, 50mm M19 screw, steel M20 screw, steel M21 screw, steel

Results Calculation of the primary energy content for the construction of four typical outside wall structures (life-cycle-elements A1-A3) PENR: Non-renewable primary energy content Primary energy content (non-renewable, A1-A3) [MJ/m²] External wall with thermal insulation Insulated and ventilated outside wall with curtain brick sheeting on a substructure Insulated and ventilated two- shelled brickwork outside wall Insulated and ventilated outside wooden post-and-beam wall Primary energy content (total, A1-A3) [MJ/m²] PET: Total primary energy content External wall with thermal insulation Insulated and ventilated outside wall with curtain brick sheeting on a substructure Insulated and ventilated two- shelled brickwork outside wall Insulated and ventilated outside wooden post-and-beam wall

Results Classification of the recyclability of the structure and the material connections disassembly [1…5] compatibility [1…5] able to be undone without damage of the components only able to be undone with damage or destruction of the components compatible incompatible compatibility of materials - poor separability - poor recyclability + good separability - separated recycling + collective recycling transformable modular disassembly [1…5] external wall with thermal insulation compatibility [1…5] insulated and ventilated outside wall with curtain brick sheeting on a substructure disassembly [1…5] compatibility [1…5] insulated and ventilated two- shelled brickwork outside wall disassembly [1…5] compatibility [1…5] Insulated and ventilated outside wooden post- and-beam wall disassembly [1…5] compatibility [1…5] Classification of the recyclability of the structure and the material connections after the ability to be disassembled and the comptability for processing of the material pairs

Acknowledgement The investigation has been conducted in the context of the Robert Bosch Juniorprofessur “Nachhaltiges Bauen” at the Institute for Lightweight Structure and Conceptual Design (ILEK) at the University of Stuttgart and has been supported by the Robert Bosch Foundation.