Hemp Composite Material Samples as an Alternative for Construction in Bhutan

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21110%2F25%3A00385096" target="_blank" >RIV/68407700:21110/25:00385096 - isvavai.cz</a>

Result on the web

<a href="https://www.researchgate.net/publication/395457104_Hemp_Composite_Material_Samples_as_an_Alternative_for_Construction_in_Bhutan" target="_blank" >https://www.researchgate.net/publication/395457104_Hemp_Composite_Material_Samples_as_an_Alternative_for_Construction_in_Bhutan</a>

DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Hemp Composite Material Samples as an Alternative for Construction in Bhutan

Original language description

The research and samples production investigates the potential use of hemp composite materials for construction in Bhutan. Two types of binder, lime and earth, are being explored for an application in two different construction elements. First one is a basic hempcrete block produced in manual sliding mold. Second type of element is an application of hemp composite as an infill material in lightweight staggered timber frame structure with diagonally woven bamboo lattice for lateral stability and infill support. This paper focuses on a production of samples of different mixtures and its application in construction and the process of obtaining raw materials in context of Bhutan where hemp cultivation is nonexistent and resources limited. Testing the material composite for compression strength, density, thermal conductivity and fire resistancy will be done in the later stage of the research. This research is part of Rural Housing Project under Bhutanese CSO Tarayana Foundation. Since 2003, Tarayana Foundation has supported construction of more than 2,600 houses in rural Bhutan. With over 2,000 new requests pending, the Foundation is moving towards a next phase with aim to provide not just more but better homes with focus on sustainability and resilience to climate change. To research this topic and find most suitable solutions for rural community construction, 3 prototype buildings are currently under construction with support from Karuna Foundation. The availability of industrial insulation materials in Bhutan are limited and practice of using it almost non-existing. Hemp, as a naturally sourced alternative for insulation, can be found growing abundantly around the Kingdom but its cultivation or collection is considered illegal. But a research and prototyping is currently being conducted in collaboration with Bauhaus Earth (Berlin), Tarayana Foundation (Bhutan) and author’s PhD research (Czech Technical University). Two types of binder, lime and earth, in various mixtures, sizes of hemp hurds and with different compaction ratios will be tested for compression strength, thermal conductivity, density and fire resistance. This tests and prototyping are being conducted in Bauhaus Earth Berlin laboratory and than repeated in Bhutan in TSHAR Institute and prototyped on Rural Housing Project under Tarayana Foundation. Two construction elements are currently used in the real construction - prefabricated hempcrete block and in-situ casted hempcrete infill in timber frame. In general, advantages of using hemp in construction are well known and researched so this research focuses more on its feasibility in context of Bhutan. As hemp is not cultivated here and grows scattered around the countryside its collection is difficult. Fortunately Tarayana F. has great outreach and connections with rural communities in remotest areas. Therefore hemp for prototype construction is harvested by rural communities, leaves and branches are removed and stalks are let for retting in the field before transporting to site. Debarking is done manually as decortication machine is not available. For hurd processing (grinding stalks into small particles) a simple wood chipper machine is used instead. Prefabricated hempcrete blocks are produced in TSHAR Institute in Mongar using a simple sliding mold and manual compacting to produce block of 20x20x40 cm with 2 cylindrical holes on centre. The aim is to create a product comparable with other options available on market, specifically fly ash AAC block which has similar structural and insulation properties. But due to manual harvesting and processing the price per block is still much higher. In-situ casted hempcrete infill in timber frame wall is applied on two prototype houses, one in TSHAR Institute and other in Gomche village at Paro.

Czech name

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Czech description

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Type

G_funk - Functional sample

CEP classification

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OECD FORD branch

20101 - Civil engineering

Project

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Continuities

V - Vyzkumna aktivita podporovana z jinych verejnych zdroju

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Internal product ID

Hemp_composite_samples_1, 2 & 3

Numerical identification

D1.1_Hemp_composite_samples

Technical parameters

Testing sample size: 14 x 14 x 14 cm Quantity of materials for 1 samples in batch: 1. Hemp: 289.75 g, Lime: 445.75 g, Water: 733.63 g 2. Hemp: 312.5 g, Lime: 360 g, Water: 595 g 3. Hemp: 327.63 g, Earth: 1119 g, Water: 250 g Block size: 200 x 400 x 200 mm in size with two cylindrical holes of 50 mm diameter

Economical parameters

Estimated price of block of 200 x 400 x 200 mm size made in the same way as the sample is around 2.98,- USD per peace including materials and labour

Application category by cost

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Owner IČO

68407700

Owner name

České vysoké učení technické v Praze / FSv / katedra konstrukcí pozemních staveb

Owner country

CZ - CZECH REPUBLIC

Usage type

V - Výsledek je využíván vlastníkem

Licence fee requirement

N - Poskytovatel licence na výsledek nepožaduje licenční poplatek

Web page

https://www.researchgate.net/publication/395457104_Hemp_Composite_Material_Samples_as_an_Alternative_for_Construction_in_Bhutan