Influence of Hemp Shives Size on Hygro-Thermal and Mechanical Properties of a Hemp-Lime Composite.

Przemysław Brzyski,Monika Rumińska,Michał Kubiś,Piotr Łapka,Karol Pietrak,Mateusz Gładecki

doi:10.3390/ma13235383

Przemysław Brzyski, Monika Rumińska + Show 4 more

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https://doi.org/10.3390/ma13235383

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Abstract

Different fractions of hemp shives are used in the mixtures of the hemp–lime composite. The market offers shives of different granulation. It depends on the type of industrial hemp and on the capabilities of decortication machines. The aim of the research presented in the article is to check differences in the mechanical and hygro-thermal properties of composites with different shives fractions. The research part of the paper presents the preparation method and investigation on hemp–lime composites. Apparent density, total porosity, thermal conductivity, capillary uptake, vapor permeability, specific heat, mass absorptivity, flexural and compressive strength were examined. The results confirm that the shives fraction influences the individual properties of the composites. Hemp–lime composites with fine shives are characterized by higher water absorption, thermal conductivity, mechanical strength, vapor permeability as well as lower capillary-lifting capacity and specific heat than composites with thick shives.

Highlights

The hemp–lime composite is an insulating material based on a lime binder and a filler in the form of pieces of the wooden part of the industrial hemp stem called hemp shives
Different fractions of hemp shives are used in the mixtures of the hemp–lime composite
The results presented in this paper may be helpful in selecting the appropriate fraction of shives for a specific application

Summary

Introduction

The hemp–lime composite is an insulating material based on a lime binder and a filler in the form of pieces of the wooden part of the industrial hemp stem called hemp shives. Hemp lime composite is usually used as an insulating material for filling a timber frame wall. By choosing the right mixture it is possible to use composite as a load-bearing material in the form of wall blocks. Properties of the composite are influenced by many factors, including the proportion of binder to shives, type of binder, and degree of compaction. With the increase in compaction force, the thermal conductivity [6] and strength parameters [7] of the composite increase. Hemp shives have a significant influence on the mechanical and hygro-thermal properties of the composite

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