Hemp Lime Concrete (HLC)A carbon-negative construction material

Didier Lesueur – Materials R&D ManagerGRD meeting – Limelette – April 6th 2011

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Outline

• Hemp Lime Concrete

• Regulation and Application

• Practical Examples

• Conclusions

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Outline

• Hemp Lime Concrete

• Regulation and Application

• Practical Examples

• Conclusions

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What is Hemp Lime Concrete?

Hemp Lime Concrete

Additives& Admixtures

Water

HempShiv

Aggregate

HydratedLime

Hydraulic Binder

Dry Mix

Binder

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Why lime?

• Hemp shiv has a huge water demand

• Lime imparts good water retention

• Hence a balanced competition for water• Otherwise,

flouring risk with purely hydraulic binders

source: Y. Hustache, Synthèse des Connaissances sur les mortiers et bétons de chanvre, Lhoist/CenC, 2008

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Roof Wall Screed Render

110 220 280 600kg binder / m³

Different types of Hemp Lime Concrete

With different binder concentration:

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Hemp Lime ConcreteRelative Properties

• Low Compressive Strength Need load bearing structure

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75

HLC

AAC

Clay Bricks

SLB

Concrete

Compressive strength (MPa)

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Hemp Lime ConcreteRelative Properties

• Good thermal insulation performance¬ 2-3 times thicker HLC layer than traditional insulation¬ 10 times better than traditional cement concrete

0.1-0.2 AAC

0.04 Exp. PolyStyrene / Mineral Wool

1 Concrete

0 Perfect insulation

0.026 Air

λ thermal conductivity

(W/m/K)

0.3-0.5 Clay brick

0.07-0.11: HLC

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Hemp Lime ConcreteRelative Properties

• Thermal dampening better than expected from static thermal conductivity

0

5

10

15

20

3 7 11 15 19 23 27 31 35 39 43 47

Outside temperature

Hemp Lime Concrete

Aerated concrete

Wood + insulation

Inside wall temperature vs outside daily 0-20°C temperature cycle

Hours

Insulatedbrick

0

5

10

15

20

3 7 11 15 19 23 27 31 35 39 43 47

Outside temperature

Hemp Lime Concrete

Aerated concrete

Wood + insulation

Inside wall temperature vs outside daily 0-20°C temperature cycle

Hours

Insulatedbrick

source: A. Evrard, Ph. D. Thesis, UCL, 2008

U = 0.44 W/m2/K

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Hemp Lime ConcreteRelative Properties

• Unique hygrothermal behaviour

• Allows humidity regulation and good thermal dampening¬ Shiv / binder porosity

stores and releases humidity

¬ Water sorption / evaporation improves thermal dampening (Phase Change Material)

• Yields superior comfort perception

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Tradical® Hemcrete® (2007) Cavity Wall (1970’s)

Hemp Lime ConcreteThermal Performance

Thermographic Images

source: I. Mawditt, Living Space Sciences, 2008

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Hemp Lime ConcreteRelative Characteristics

• Negative carbon-footprint

-0,4-0,2

00,20,40,60,8

11,21,41,6

kg eq CO2 /m²/year

clay brick (monomur)

Aerated Concrete

Concrete + insulation

HLC

source: M.-P. Boutin et al., INRA, 2005

over 100 years

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Outline

• Hemp Lime Concrete

• Regulation and Application

• Practical Examples

• Conclusions

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Hemp Lime ConcreteRegulation

• France¬ Règles

professionnelles

• UK• BBA / LABC approved

• Wallonia• Entering the list of

accepted insulation materials

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Placed between shutters...

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... or sprayed

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Shutters can be removed after 24 hours

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Final render applied after ~ a month

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Outline

• Hemp Lime Concrete

• Regulation and Application

• Practical Examples

• Conclusions

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Industrial

Renovation

Hemp Lime ConcreteUsed in all construction categories

New

Multiple housing

Commercial

Single housing

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• Maison Diocésaine Odette Prévost (2004)¬ Chalons-en-Champagne (F)¬ Architect: Atelier Méandre ¬ Observ’ER Award 2006 ¬ « Insulation » of the stones walls

with an hemp plaster (5 to 7 cm)

Renovation work

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New industrial building

• Adnams Distribution Center (2006)¬ Southwold (UK)¬ Architect:

Aukett Fitzroy Robinson

¬ David Alsop Sustainability Award 2007

¬ No air cooling system (400 000 £ saved)

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New industrial building

• Wine Society (2009)¬ Stevenage (UK)¬ Architect: Vincent &

Gorbing¬ 400,000 kWh of gas +

electricity saved each year (compared to project)

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New industrial building

• Marks & Spencer (due 2011)¬ Cheshire Oaks (UK)¬ Architect: Aukett Fitzroy

Robinson ¬ M&S biggest store outside

London (14 000 m2)

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New private or social housing

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Outline

• Hemp Lime Concrete

• Regulation and Application

• Practical Examples

• Conclusions

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Hemp Lime ConcreteConclusion and Perspectives

• Carbon-negative construction material¬ Wall, floor and roof insulation¬ Phase Change Material with dynamic thermal properties

better than predicted from static thermal conductivity

• Growing number of projects• 20 years of experience in France (> 10 000 references)• 5 years of experience in the UK (> 250 references)• Emerging in Belgium• Project size is increasing (UK first, now France)

• Technical challenges ahead• How to take into account the PCM effect in buildings

thermal design?• Reach industrial application rates (faster drying...)