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Hemp concretes

mechanical properties using both shives and fibres

de Bruijn, Paulien (2008). Hemp concretes. Alnarp : Sveriges lantbruksuniv. ; -
ISBN 978-91-85911-87-5
[Licentiate thesis]

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Abstract

Hemp (Cannabis sativa) is an agricultural crop that can be used as a building material in combination with lime and cement. A composite building material that combines a cementitious binder (building limes and cement) with hemp shives, the woody core of the hemp stalk is generally referred to as hemp concrete (HC). However, industrial facilities to separate hemp shives and fibres are currently not available in Sweden. HC has many advantages as a building material but it is not load-bearing and must be used in combination with a load-bearing wooden frame. The aim of this research was to elucidate the feasibility of using both hemp shives and fibres in a HC to determine an optimal mix of the different binding agents and to investigate if adding undensified microsilica to the mix and using calcinated gypsum as a binder would improve mechanical strength of the material. The effects on compressive strength of pre-mixing the binder or creating perforations in the test specimens were also investigated. Cube and cylinder specimens cured for 40 days in a carbonation room (4.5 vol% CO2) were tested for mechanical properties, water sorption and frost resistance. Including more hydraulic lime or undensified microsilica in the mix did not significantly affect mechanical strength, whereas adding more cement to the mix increased mechanical strength. Calcinated gypsum as a binder gave mechanical properties of the same magnitude of a contemporary HC. Pre-mixing the binder created a more homogeneous material but it did not seem to play an important role in final mechanical properties. The perforations created in some of the test specimens produced a material with a lower Young’s modulus and higher deformation at rupture. Using both shives and fibres in a hemp concrete may be a suitable approach in Sweden until facilities for separating hemp fibres from shives become available.

Authors/Creators:de Bruijn, Paulien
Title:Hemp concretes
Subtitle:mechanical properties using both shives and fibres
Year of publishing :2008
Volume:-
Number of Pages:47
Papers/manuscripts:
NumberReferences
ALLI. de Bruijn, P.B., Jeppsson, K-H., Sandin, K. & Nilsson, C. (2008). Mechanical properties of lime-hemp concretes containing shives and fibres. Submitted to an international peer-reviewed journal II. de Bruijn, P.B., Jeppsson, K-H. & Nilsson, C. (2008). The effect of silica, gypsum, pre-mixing and perforation on mechanical properties on hemp concretes. Submitted to an international peer-reviewed journal
Place of Publication:Alnarp
Publisher:Dept. of Rural Buildings and Anmal Husbandry
ISBN for printed version:978-91-85911-87-5
ISSN:-
Language:English
Publication Type:Licentiate thesis
Full Text Status:Public
Agris subject categories.:X Agricola extesions > X60 Technology
Subjects:Not in use, please see Agris categories
Agrovoc terms:hemp, cannabis sativa, gypsum, silica, concrete, construction materials, technical properties
Keywords:hemp, building material, lime, cement, gypsum, carbonation, shives, silica, lime-hemp concrete.
URN:NBN:urn:nbn:se:slu:epsilon-2779
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-2779
ID Code:1913
Department:(LTJ, LTV) > Rural Buildings and Animal Husbandry (until 121231)
Deposited By: Paulien de Bruijn
Deposited On:04 Mar 2009 00:00
Metadata Last Modified:02 Dec 2014 10:15

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