Where I’m at now • University of Bath • Department of Architecture & Civil Engineering (ACE) • BRE Centre for Innovative Construction Materials • EPSRC CDT in Decarbonisation of the Built Environment 2017-10-11 'Building out of poverty - Alastair Marsh' 3
My team Dept of Architecture & Civil Engineering, University of Bath Prof Andrew Heath Dr Mark Evernden Prof Pete Walker Dr Pascaline Patureau, Prof Venkatarama Reddy, Dept of Chemistry, University of Bath Indian Institute of Science 2017-10-11 'Building out of poverty - Alastair Marsh' 4
My backstory • Materials Science MEng (2009-13) • Graduate Sustainability & Physics Engineer (2013-15) • University of Bath, PhD (2015-18) 2017-10-11 'Building out of poverty - Alastair Marsh' 5
My backstory • Construction training charity • Interlocking stabilised soil blocks (ISSB) • Replacement for cement? 2017-10-11 'Building out of poverty - Alastair Marsh' 6
Part I – the problems of housing 2017-10-11 'Building out of poverty - Alastair Marsh' 7
Draw your dream home! • Location? • Materials? • Type of home? • View? • Colour scheme? 2 minutes… 2017-10-11 'Building out of poverty - Alastair Marsh' 8
Demographic context of housing 2014 population growth rates, World Bank 2017-10-11 'Building out of poverty - Alastair Marsh' 9
Demographic context of housing UNDESA, 2015. World Population Prospects: The 2015 Revision, Key Findings and Advance Tables. Working Paper No. ESA/P/WP.241. 2017-10-11 'Building out of poverty - Alastair Marsh' 10
Demographic context of housing UN-HABITAT, 2014. World Habitat Day: Background Paper. Nairobi. UNDESA, 2014. World Urbanization Prospects: The 2014 Revision, Highlights (ST/ESA/SER.A/352). UNDESA, 2015. World Population Prospects: The 2015 Revision, Key Findings and Advance Tables. Working Paper No. ESA/P/WP.241. 2017-10-11 'Building out of poverty - Alastair Marsh' 11
Informal construction sector 1. Self-building 2. Stockpiling 3. Materials spectrum 4. Insecurity of tenure By Claudio Allia (Own work) [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons 2017-10-11 'Building out of poverty - Alastair Marsh' 12
Informal settlement or slum? • Informal settlement = HOW it’s built • Slum = WHAT this settlement is i.e. inadequate, By Claudio Allia (Own work) [CC BY-SA 3.0 overcrowded (https://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons Slum Dwellers International (SDI) www.sdinet.org www.sdinet.org 2017-10-11 'Building out of poverty - Alastair Marsh' 13
Current walling materials used • More durable • Higher social status • More expensive • Higher impact UN-HABITAT, 2009. INTERLOCKING STABILISED SOIL BLOCKS: Appropriate earth technologies in Uganda. Nairobi: UN-HABITAT. 2017-10-11 'Building out of poverty - Alastair Marsh' 14
Informal construction Pros? Cons? • Very cheap • Structural quality • Flexible • Internal environment • Construction safety • Expensive transport • Waste • Lack of materials innovation 2017-10-11 'Building out of poverty - Alastair Marsh' 15
Respecting existing… Attitudes Processes Marsh, A. et al., 2016. A Holistic Materials Design Requirements Framework (HoMDReF) For Future Housing Materials. Integrated Design at 50: Building our Future . Rwanda Cricket Ground design, Light Earth Designs LLP 2017-10-11 'Building out of poverty - Alastair Marsh' 16
Broad research question It’s got to be… • Affordable • Practical • Sustainable • Aspirational Put another option on the table The best of earth and the best of concrete? 2017-10-11 'Building out of poverty - Alastair Marsh' 17
Puzzle #1! 2017-10-11 'Building out of poverty - Alastair Marsh' 18
Part II – geopolymers and stabilised soil materials 2017-10-11 'Building out of poverty - Alastair Marsh' 19
What is soil? = “uncemented or weakly cemented accumulation of mineral particles formed by the weathering of rocks as part of the rock cycle, the void space between the particles containing water and/or air .” = clay + other minerals Knappett, J. (2012). Craig's soil mechanics. Abingdon, Abingdon : Spon. Reeves, G. M., et al. (2006). Clay materials used in construction. London, London : Geological Society. 2017-10-11 'Building out of poverty - Alastair Marsh' 20
What are clay minerals? • Alumino-silicates = mostly aluminium, silicon, oxygen and hydrogen (plus some minor others) • Sheet structure Knappett, J. (2012). Craig's soil mechanics. Abingdon, Abingdon : Spon. Reeves, G. M., et al. (2006). Clay materials used in construction. London, London : Geological Society. 2017-10-11 'Building out of poverty - Alastair Marsh' 21
Unstabilised soil materials Hope Cove, Devon Shibam, Yemen By Nilfanion (Own work) [CC BY-SA 3.0 By Goldzahn [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0) or GFDL (https://creativecommons.org/licenses/by-sa/3.0)], via (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons Wikimedia Commons 2017-10-11 'Building out of poverty - Alastair Marsh' 22
Stabilised soil materials How to stabilise? • Mechanical • Compaction • Grading • Chemical • Cement • Lime • Other…? 2017-10-11 'Building out of poverty - Alastair Marsh' 23
Stabilised soil materials Why stabilise soil to build with? • Maintenance • Termites • Lifestyle • Aesthetics Images courtesy of Haileybury Youth Trust 2017-10-11 'Building out of poverty - Alastair Marsh' 24
Geopolymers = amorphous, synthetic, alkali aluminosilicates � � ��� 2 � ��� 2 � Davidovits, J., 2011. Geopolymer chemistry and applications. 3rd ed. ed. Saint-Quentin: Saint-Quentin : Institut Geopolymere. 2017-10-11 'Building out of poverty - Alastair Marsh' 25
Geopolymer formation reaction • Four stages • Disassembly, then reassembly 2017-10-11 'Building out of poverty - Alastair Marsh' 26
Why are we interested? Pros Cons • Low temperature • High pH solutions reaction low required embodied energy • Starting materials - can • Reaction still not fully use abundant or waste understood materials • Properties • Strength • Durability • Fire resistance • Acid resistance 2017-10-11 'Building out of poverty - Alastair Marsh' 27
Geopolymer stabilised soil materials (GSSM) = use geopolymer phase to stabilise soil = geopolymer reaction transforms clay in soil into a geopolymer Could GSSM be… • Affordable? • Practical? • Aspirational? • Sustainable? 2017-10-11 'Building out of poverty - Alastair Marsh' 28
Why are we interested? Footprint of GSSM • NaOH • “Firing” Hischier, R., et al. (2010). Implementation of life cycle impact assessment methods. Ecoinvent Report. Hammond, G. and Jones, C. (2011). Inventory of carbon & energy (ICE). Sustainable Energy Research Team (SERT). Version, 1. Hashemi, A., Cruickshank, H. & Cheshmehzangi, A., 2015. Environmental Impacts and Embodied Energy of Construction Methods and Materials in Low-Income Tropical Housing. Sustainability , 7(6), p. 7866. Maskell, D., 2013. Development of Stabilised Extruded Earth Masonry Units. 2017-10-11 'Building out of poverty - Alastair Marsh' 29
Problems with GSSM Unknowns • How much activating NaOH do we need? • Which soils does this reaction work on? • How to make the optimal ‘recipe’ for a given soil? 2017-10-11 'Building out of poverty - Alastair Marsh' 30
My research Comparison of pure clay Predict behaviour of real minerals’ behaviour soil Is this technology feasible for all soil types? Or just a small fraction? 2017-10-11 'Building out of poverty - Alastair Marsh' 31
Manufacture 2017-10-11 'Building out of poverty - Alastair Marsh' 32
Manufacture 2017-10-11 'Building out of poverty - Alastair Marsh' 33
Methods • Which phases are present? • How much of each phase is present? • How are they distributed? 1x10 -1 m 1x10 -2 m 1x10 -3 m 1x10 -4 m 1x10 -5 m 1x10 -6 m 1x10 -7 m 1x10 -8 m 1x10 -9 m 1x10 -10 m 2017-10-11 'Building out of poverty - Alastair Marsh' 34
Magic Angle Spinning Nuclear Magnetic Resonance (MAS-NMR) • Uses magnetic pulses • Information about atomic bonding coordination • Shows change from sheet to network coordination on reaction 1x10 -1 m 1x10 -2 m 1x10 -3 m 1x10 -4 m 1x10 -5 m 1x10 -6 m 1x10 -7 m 1x10 -8 m 1x10 -9 m 1x10 -10 m 2017-10-11 'Building out of poverty - Alastair Marsh' 35
Powder X-ray diffraction (XRD) • Uses single wavelength X-ray radiation • Identifies crystalline phases present • More difficult for geopolymers, as these are non-crystalline . 1x10 -1 m 1x10 -2 m 1x10 -3 m 1x10 -4 m 1x10 -5 m 1x10 -6 m 1x10 -7 m 1x10 -8 m 1x10 -9 m 1x10 -10 m 2017-10-11 'Building out of poverty - Alastair Marsh' 36
Scanning electron microscopy (SEM) • Like a light microscope - but with Clay electrons. • Shows microstructure Geopolymer- stabilised clay 1x10 -1 m 1x10 -2 m 1x10 -3 m 1x10 -4 m 1x10 -5 m 1x10 -6 m 1x10 -7 m 1x10 -8 m 1x10 -9 m 1x10 -10 m 2017-10-11 'Building out of poverty - Alastair Marsh' 37
Recommend
More recommend
