Comparing the Environmental Impact of Stabilisers for Unfired Earth Construction

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Abstract:

Buildings account for approximately one third of the total worldwide energy emissions, of which approximately a quarter can be attributed to the embodied energy of the building. Current UK legislation for low-energy homes is only concerned with operational energy. Embodied energy, and carbon, is not currently considered but over the design life of an average building is expected to make a significant contribution to the total whole life energy used. Earthen building materials contribute to reduce energy consumption in use through their passive regulation of temperature and humidity. In addition, there can also be significant embodied energy savings compared to other materials. Traditional methods of earthen construction, using locally sourced materials and manual labour require minimal energy for the transport and construction. A greater uptake of earth construction is likely to come from modern innovations such as industrialised manufacture. Extruded fired brick manufacturing processes has the potential to produce a high quality, low cost and low energy product suitable for the mainstream construction sector in both developed and developing nations. By not firing the extruded clay bricks, an embodied energy saving of 86% can be achieved, compared to fired clay, and 25% compared to concrete blocks. However, there are limitations to the structural use of unstabilised earth bricks due to the loss of strength under high moisture content conditions. The use of traditional and novel stabilisation methods can be adopted to address the concerns over strength and durability. Cement and lime are widely used in some countries, but both significantly increase material embodied energy and carbon and can inhibit passive humidity regulation. The paper presents results from a study of the embodied energy of various stabilisers used for unfired clay materials. The Global Warming Potential (GWP) is a measure of the equivalent carbon dioxide that allows for the relative weightings of damaging greenhouse gasses. Both the embodied energy and the GWP figures of various stabilisers are compared and discussed. The conclusion of the work is that there is a maximum quantity of stabiliser than should be used. Typically the quantities of stabiliser are quoted as the amount that gives the maximum strength, but this should take account of not only strength but the environmental impact of achieving the improvement.

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132-143

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March 2014

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[1] BIS (2010). Estimating the amount of CO2 emissions that the construction industry can influence. Supporting material for the Low Carbon Construction IGT Report. Department for Business, Innovation and Skills.

Google Scholar

[2] Burroughs, S. (2008). Soil property criteria for rammed earth stabilization. Journal Of Materials In Civil Engineering, 20(3), 264-273.

DOI: 10.1061/(asce)0899-1561(2008)20:3(264)

Google Scholar

[3] Frischknecht, R., Jungbluth, N., Althaus, H., Doka, G., Dones, R., Heck, T., Hellweg, S., Hischier, R., Nemecek, T., Rebitzer, G., et al. (2005).

DOI: 10.3370/lca.1.112

Google Scholar

[4] Habert, G., d'Espinose de Lacaillerie, J., and Roussel, N. (2011). An environmental evaluation of geopolymer based concrete production: reviewing current research trends. Journal of Cleaner Production, 19(11): 1229 – 1238.

DOI: 10.1016/j.jclepro.2011.03.012

Google Scholar

[5] Hammond, G. & Jones, C. (2011). Inventory of carbon \& energy (ICE). Sustainable Energy Research Team (SERT). Version, 1.

Google Scholar

[6] Heath, A., Goodhew, S., Paine, K., Lawrence, M., & Ramage, M. (2012). The potential for using geopolymer concrete in the UK. Construction Materials.

DOI: 10.1680/coma.12.00030

Google Scholar

[7] Heath, A., Maskell, D., Walker, P., Lawrence, M., & Fourie, C. (2012). Modern earth masonry : Structural properties and structural design. The Structural Engineer, 90(4), 38–44.

Google Scholar

[8] Hischier R., Weidema B., Althaus H. -J., Bauer C., Doka G., Dones R., Frischknecht R., Hellweg S., Humbert S., Jungbluth N., Köllner T., Loerincik Y., Margni M., and Nemecek T. (2010).

Google Scholar

[9] Houben, H. & Guillaud, H. (1994). Earth construction: a comprehensive guide. Intermediate Technology Publications. ISBN: 9781853391934.

Google Scholar

[10] Jaquin, P., Augarde, C., Gallipoli, D., & Toll, D. (2009). The strength of unstabilised rammed earth materials. Géotechnique., 59(5), 487–490.

DOI: 10.1680/geot.2007.00129

Google Scholar

[11] Lawrence, R., Heath, A. C., & Walker, P. (2008). Mortars for thin unfired clay masory walls. In Proceedings of LEHM 5th International conference on Building with Earth, Koblenz, Germany (pp.66-73).

Google Scholar

[12] Maskell, D., Walker, P., & Heath, A. (2012). The compressive strength of lignosulphonate stabilised extruded earth masonry units. In Terra 2012: 11th International Conference on the Study and Conservation of Earthen Architecture Heritage.

Google Scholar

[13] Metz, B. and Davidson, O. (2007). Climate Change 2007: Mitigation: Contri- bution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Intergovernmental Panel on Climate Change.

DOI: 10.1017/cbo9781107415416

Google Scholar

[14] Morton, T. (2008). Earth Masonry: Design and Construction Guidelines. IHS BRE press. ISBN: 9781860819780.

Google Scholar

[15] Morton, T. (2006). Feat of clay. Materials world, 14(1), 2–3.

Google Scholar

[16] Oti, J. E., Kinuthia, J. M., & Bai, J. (2009). Engineering properties of unfired clay masonry bricks. ENGINEERING GEOLOGY, 107(3-4), 130-139.

DOI: 10.1016/j.enggeo.2009.05.002

Google Scholar

[17] Reddy, B. & Gupta, A. (2006). Strength and elastic properties of stabilized mud block masonry using cement-soil mortars. JOURNAL OF MATERIALS IN CIVIL ENGINEERING, 18(3), 472-476.

DOI: 10.1061/(asce)0899-1561(2006)18:3(472)

Google Scholar

[18] Reddy, B. V. V. (2004). Sustainable building technologies. Current Science, 87(7), 899–907.

Google Scholar

[19] Reddy, B. V. V. & Jagadish, K. (2003). Embodied energy of common and alternative building materials and technologies. Energy and Buildings, 35(2), 129–137.

DOI: 10.1016/s0378-7788(01)00141-4

Google Scholar

[20] Reddy, B. V. V. & Kumar, P. P. (2010). Embodied energy in cement stabilised rammed earth walls. Energy and Buildings, 42(3), 380 - 385.

DOI: 10.1016/j.enbuild.2009.10.005

Google Scholar

[21] Santoni, R. L., Tingle, J. S., & Nieves, M. (2005). Accelerated strength improvement of silty sand with nontraditional additives. Transportation Research Record: Journal of the Transportation Research Board, 1936(-1), 34–42.

DOI: 10.1177/0361198105193600105

Google Scholar

[22] Solomon, S. (2007). Climate change 2007: contribution of working group I to the fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press. ISBN.

DOI: 10.1080/01944363.2014.954464

Google Scholar

[23] Sturgis, S. & Roberts, G. (2010). Redefining Zero: Carbon profiling as a solution to whole life carbon emission measurement in buildings. RICS Research Report, RICS, London.

Google Scholar

[24] Tingle, J. S., Newman, J. K., Larson, S. L., Weiss, C. A., & Rushing, J. F. (2007). Stabilization mechanisms of nontraditional additives. Transportation Research Record, 2(1989), 59-67.

DOI: 10.3141/1989-49

Google Scholar

[25] Walker, P. (2004). Strength and erosion characteristics of earth blocks and earth block masonry. Journal Of Materials In Civil Engineering, 16(5), 497-506.

DOI: 10.1061/(asce)0899-1561(2004)16:5(497)

Google Scholar