Hempcrete

Hempcrete is a mixture of hemp hurds (shives) and lime (possibly including natural hydraulic lime,[1] sand, pozzolans or cement) used as a material for construction and insulation.[2] It is marketed under names like Hemcrete, Canobiote, Canosmose, and Isochanvre.[3] Hempcrete is easier to work than traditional lime mixes and acts as an insulator and moisture regulator. It lacks the brittleness of cement and consequently does not need expansion joints.[3]

However, the typical compressive strength is around 1 MPa,[4] over 20× lower than low grade concrete. Hempcrete walls must be used together with a frame of another material that supports the vertical load in building construction. Hempcrete's density is 15% of traditional concrete, as well as carbon negative.[5] Like other plant products, the hemp crop absorbs CO2 gas as it grows, retaining the carbon and releasing the oxygen. 165 kg of carbon can be theoretically absorbed and locked up by 1 m3 of hempcrete wall over many decades.[6]

References

  1. ^ Allin, Steve. Building with Hemp, Seed Press, 2005, ISBN 978-0-9551109-0-0. (p. 146, 1st Edition).
  2. ^ "NNFCC Renewable Building Materials Factsheet: An Introduction". National Non-Food Crops Centre. February 21, 2008. http://www.nnfcc.co.uk/publications/nnfcc-renewable-building-materials-factsheet-an-introduction. Retrieved 2011-02-16. 
  3. ^ a b Priesnitz, Rolf B. (March/April 2006). "Hemp For Houses". Natural Life Magazine. http://www.naturallifemagazine.com/0604/hemphouse.htm. 
  4. ^ "Tradical Hemcrete 2008 Information Pack" (PDF). American Lime Technology. http://www.americanlimetec.com/tech_sheets.php?file=PDF_file&recid=12.21&h=447447697558567941. Retrieved 2009-08-25. 
  5. ^ Flahiff, Daniel (August 24, 2009). "Carbon Negative Hemp Walls are 7x Stronger than Concrete". Inhabitat. http://www.inhabitat.com/2009/08/24/hemcrete-carbon-negative-hemp-walls-7x-stronger-than-concrete/.  (Despite the article title, the "7x stronger" claim is contradicted by the text: "Hemcrete® is not stronger than concrete.")
  6. ^ "Tradical Hemcrete 2008 Information Pack" (PDF). American Lime Technology. http://www.americanlimetec.com/tech_sheets.php?file=PDF_file&recid=12.21&h=447447697558567941. Retrieved 2010-05-15. 

External links