Study on strength and microstructure of hempcrete

Abstract

Hempcrete is a mixture of natural hemp fibre and lime or other cementitious material in a desired mix proportion to utilize as a green building product. This composite is being used for producing non- loading building material and applied in the construction work along with the frame work made up of timber or steel. It is a very eco-friendly building material which is reducing carbon foot print in low cost construction activities, containing less embodied energy, used as a thermal and humidity control acoustic material. In this study various binder mix ratios were tried to find out optimal mix ratio of the binder to make hempcrete by using hemp fibre. Further investigation was carried out to assess the impact on strength of hempcrete due to addition of mineral admixtures like silica fumes, Meta-kaolin, Fly ash with lime and cement at various proportions. The test specimens of 150mmx150mmx150mm hempcrete cubes were cast 6 numbers in each mix proportion and allowed to dry in the ambient conditions for 24 hours to attain optimum moisture content and mass of each specimen is measured. Then the specimens are kept in the carbonation chamber and exposed to 2 bar pressure of pure CO2 gas (commercially available) after 24 hours of carbonation curing they are removed and weighed again and tested after 28 days for compressive strength. The mix combination which contains hydrated lime with silica fumes as admixture did not significantly affect the compressive strength, whereas adding Meta-kaolin as an admixture to the mix increased strength. The specimens that have hemp fibers with lime and meta-kaolin showed better results on carbon dioxide sequestration and compressive strength.Hempcrete is a mixture of natural hemp fibre and lime or other cementitious material in a desired mix proportion to utilize as a green building product. This composite is being used for producing non- loading building material and applied in the construction work along with the frame work made up of timber or steel. It is a very eco-friendly building material which is reducing carbon foot print in low cost construction activities, containing less embodied energy, used as a thermal and humidity control acoustic material. In this study various binder mix ratios were tried to find out optimal mix ratio of the binder to make hempcrete by using hemp fibre. Further investigation was carried out to assess the impact on strength of hempcrete due to addition of mineral admixtures like silica fumes, Meta-kaolin, Fly ash with lime and cement at various proportions. The test specimens of 150mmx150mmx150mm hempcrete cubes were cast 6 numbers in each mix proportion and allowed to dry in the ambient conditions for 24 ho...