EVALUATION OF HEMP STRAW AND FIBRE STRENGTH

In recent years, there is a growing interest for the use of natural materials in composite applications, where cellulose materials are reinforced in foam gypsum matrix. A result is environmentally friendly low density building material, which can show high tensile and compressive strength, good heat and sound insulation properties. Hemp (Cannabis sativa L.) fibres are natural fibres and their properties vary according to the plant growing regional climatic conditions, fertilizers, plant density, harvesting time and pre-treatment technological processes. The objective of the present research was to evaluate hemp straw and fibre strength to use them for gypsum reinforcement. Hemp straw compressive strength of longitudinal and transverse stresses compressing the samples between two parallel planes was established. The results show that the variety 'Bialobrzeskie' longitudinal compressive strength is 19.5 MPa on average, but the transversal strength of 1.33 MPa. Variety 'Futura 75' shoved longitudinal compressive strength 23.1 MPa, while the transverse strength is 1.32 MPa and variety 'Santhica 27' showed the values 26.4 MPa and 1.55 MPa. The hemp varieties that are suitable for reinforcement of foam gypsum fiber tensile strength were determined. The tensile strength of individual samples ranged from 273 MPa to 715 MPa.