Hemp concrete
HEMP CONCRETE
Insulation plant
ERASMUS INTENSIVE PROGRAM 2010
PASSIVE HOUSE CONCEPT
Multi-Disciplinary International Project in Passive Design & Construction
Alexandre GACOIN
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Hemp concrete
Summary
1 Hemp concrete, why?
1.1 Sustainable Development
1.2 Importance of energy-efficient buildings for the environment
2 Hemp concrete
2.1 Hemp
2.2 Lime
3. The characteristics of hemp concrete (data TRADICAL®)
3.1 Evolution of the mechanical characteristics
3.2 Energy performance
4. Implementation
4.1 Wall insulation: Wood frame
4.2 Dubbing interior insulation: mineral media
4.3 Moisture Coating: Inside/Outside
4.4 Insulation covering : Soil and floor
4.5 Roof Insulation
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Hemp concrete
1. Hemp concrete, why?
wealth
intensive use of natural resources
1.1 Sustainable Development
Throughout the nineteenth century, the
concept of economic growth was based on
economic criteria.
In the same year, the concept of sustainable
development appeared and became a
significant factor.
1.5
1
0.5
In 1970, it is estimated that man consumed
each year more natural resources than the
nature would regenerate.
humanity's accumulative ecological debt
Number of Earth
In the late twentieth, the developed countries
realized that their wealth was based on
intensive use of natural resources and that this
mode would not last.
=
1961
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1961
2009
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Hemp concrete
The concept of sustainable development was defined in 1987 by the World Commission on
Environment and Development:
"development that meets the needs of the present without compromising the ability of future
generations to meet their own needs.“
Sustainable development implies economic
growth together with the protection of
environmental quality.
Economy
Society
This form of development is a stable
relationship between human activities and the
natural world, which does not reduce the
prospects for future generations to enjoy a life
quality at least as good as our own.
Environment
The three pillars of sustainable development
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Hemp concrete
1.2 Importance of energy-efficient buildings
In the context of sustainable development, the
construction, representing for 30% to 40% of global
consumption of energy, plays a significant role.
It is urgent to reduce the impact of buildings on the
environment and to make buildings more energy-efficient:
Significantly reduce the
energy consumption of
buildings and improve
energy-efficiency
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Hemp concrete
In the fight against global warming, you must develop new resources that have an ecological,
social and economic interest .
Among these new resources, materials derived from plants are increasingly used in the buildings
due to their considerable strengths.
Hemp
Ramie
Flax
Kenaf
Jute
Bamboo
The hemp concrete combines the hemp qualities and lime qualities. Knowledge of these two
products enables the implementation of hemp concrete and optimize its performance.
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Hemp concrete
2. Hemp concrete
Hemp shives
Hemp
Hemp concrete !
+
Pure limestone
Lime
(slaked-lime)
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Hemp concrete
2.1 Hemp
Robust plant that can quickly produce large quantities of material
Its culture is very respectful for the environment
• little or no pesticides
• no fertilizers
• little water ...
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Hemp concrete
Hemp cultivation
In France
Reims
Plant cycle
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Harvest
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Hemp concrete
2.1.1 Hemp fiber
In a cross section of hemp stalk, one notices that the thick-walled cells at the periphery:
 they are fibers.
They serve to keep the right plant for its growth, and are the backbone.
When the hemp is mature, the dried fibers represent approximately 35% of the weight.
They are used for making paper pulp and for the
manufacture of wool insulation.
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Hemp concrete
2.1.2 Hemp shives
The hemp shives are the central part of the hemp stalk. It’s the wood of the hemp stalk.
It represents 45% of the weight of dried hemp.
The hemp shives are in the form of aggregates.
The hemp shives particles have a very low density and are very efficient in thermal and sound
insulation.
For building applications, the hemp shives are sifted and sorted to obtain the desired size.
They are used for making mortars and light-weighted concrete insulation
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Hemp concrete
2.2 Lime
2.2.1 Definition
The lime comes from cooking of the purest limestone up to 900 ° C .
limestone
It is a healthy material for natural buildings
• Foundation
• Mortar
• Waterproofing
• Masonry
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A limestone
quarry extraction
Hemp concrete
Water (H2O) evaporation
when drying
Surface is exposed to
Carbone dioxyde and
uses (CO2)
CARBONATION
2.2.2 The Limestone Life-Cycle
Extract
Carbon dioxyde (C02)
Water (H20)
Limestone
Calcium
Carbonate
(CaO3)
CALCINATION
(Burn at 900°C)
blast furnace
APPILCATION
Quicklime
Fresh mortar
Calcium Oxyde
(CaO)
SLAKING AGED
ADDING MINERALS
Slaked lime
Added
Water (H2O)
Calcium
Hydroxide
Ca(OH)2
powder
Adding Sand and Water
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Hemp concrete
3. The characteristics of hemp concrete (data TRADICAL®)
3.1 Evolution of the mechanical characteristics
3.1.1 Durability
• The new hemp concrete have a very good cohesion and very low density (<500kg/m3).
• He had good results with freeze-thaw tests.
°C
0
20
18
t
Hemp concrete made with pure hydraulic
binders (NHL) does not resist more than 2
cycles.
The hemp concrete TRADICAL® resists 20
cycles.
(This result is comparable only to pure limestone!)
number of cycles
16
14
12
10
8
6
4
2
0
NHL2
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NHL 3,5
NHL Z5
Tradical
PF70
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Hemp concrete
3.1.2 Compressive strength
• The tests on hemp concrete made with natural hydraulic lime NHL does not exceed the
compressive strength, (0.46 MPa).
• The hemp concrete Tradical® resists to 1.46 MPa.
2
1.8
1.6
MPa 90 days
1.4
1.2
1
0.8
0.6
0.4
0.2
0
NHL2
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NHL 3,5
NHL Z5
Tradical
PF70
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Hemp concrete
3.2 Energy performance
3.2.1 Hemp concrete and RT 2005
•The thermal transmittance of a wall is rated “U”.
It characterizes the amount of heat passing through a wall, per unit time per unit area and unit
temperature difference between the atmospheres located on both sides of the wall.
The heat transfer coefficient expressed in W / m² K is the inverse of thermal resistance (R) of the
wall. If its value is low, the construction will be well insulated.
• 26 cm concrete hemp Tradical ® provides a heat transfer coefficient U=0.38 W/m2.K,
compatible with the existing thermal regulation RT 2005.
26 cm
Outside
Inside
heat
Hemp Concrete
220 kg/m3
U=0.38 W/m2.K
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Hemp concrete
• Compared to other common materials with similar thermal resistance, “embodied energy”
requirements for the manufacture of 1m2 hemp concrete wall are low.
3
2.7
2.4
2.1
1.8
1.5
1.2
0.9
0.6
0.3
0
2.36
2.5
2.36
2.5
Embodied energy
Thermal esistance (R)
(“Embodied energy” is the sum of all the energy needed to produce, use and recycling materials
for industrial products)
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10.8
9.6
8.4
7.2
6
4.8
3.6
2.4
1.2
0
11.69
6.36
5.6
3.94
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Hemp concrete
3.2.2 Hemp concrete and RT 2010
To be consistent with the thermal regulation in 2010, the building walls must have a heat
transfer coefficient U of the order of 0.2 W/m2.K.
By varying the composition of hemp concrete can reach these values without much increase of
the wall thickness.
5 cm 26 cm
5 cm
Outside
Inside
Hemp Concrete
110 kg/m3
220 kg/m3
chaleur
U=0.2 W/m2.K
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Hemp concrete
3.2.3 Hemp concrete = Negative Carbon
Like all plants, hemp uses carbon dioxide (CO2) from the air for growth.
One hectare of hemp can use 15 tons of CO2 before its maturity.
300 round trips between Paris and London by plane!
Negative Carbon Hemp Walls are 7 times
Stronger than Concrete
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1.47
kg CO2
The impact "Greenhouse Effect" of hemp
concrete is -0.35 kg of CO2 while most
materials emit CO2 0.50 kg or more ...
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
0.49
-0.35
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0.5225
Hemp concrete
4. Implementation
4.1 Wall insulation: Wood frame
Characteristics
Composition to be determined
Density
Thermal conductivity
Compressive strength at 90 days
Air lime
Lime
putty
Water
+
60 à 70 L
Hemp
shives
Boon
+
44 kg
220 kg/m3
330 kg/m3
λ = 0,085 W/m.k
0,9 MPa
=200 L Hemp concrete
200 L
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Hemp concrete
4.2 Dubbing interior insulation: mineral media
Rough-cast=
Rough-cast=
Rough-cast=
+ +
+
+60 L sand
L sand
+60+60
L sand
Dubbing insulation
Dubbing
insulation
Dubbing insulation
dede
From
to 20
cm
de
55 à 20
20
cm
5cm
à5 20
cm
Finish Coating
Finish Coating
Finish Coating
Mortar to be determined 330 kg/m3
Density
440 kg/m3
Thermal conductivity
λ = 0,107 W/m.k
Air lime
Lime
putty
Water
+
80 à 100 L
Hemp
shives
Boon
+
66 kg
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=200 L Hemp concrete
200 L
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Hemp concrete
4.3 Moisture Coating: Inside/Outside
Rough-cast =
Rough-cast=
+
+
+60 L sable
+60 L sand
Rough-cast == +
Rough-cast
++60 L sable +60 L sand
sable
Dubbing insulation
de 5 à 20 cm
Coating
Finish Coating
Coating
Coating
Dosage
825 kg/m3
Density
935 kg/m3
Thermal conductivity λ = 0,19 W/m.k
Air lime
Lime
putty
Water
+
110 L
HempBoon
shives
=200 L Hemp
concrete
+
165 kg
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200 L
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Terracotta tile on hemp concrete floor
Wooden floor on hemp concrete
Hemp floors on wooden boards
Water
Lime
putty
Air lime
+
_80 à 100 L
Boon
Hemp
shives
+
55 kg
Composition to be determined
Density
Thermal conductivity
Compressive strength at 90 days
4.4 Insulation covering : Soil and floor
275 kg/m3
385 kg/m3
λ = 0,096 W/m.k
1,1 MPa
Hemp concrete
=200 L Hemp concrete
200 L
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Hemp concrete
4.5 Roof Insulation
Air lime
Lime
putty
Water
+
40 à 50 L
Hemp
shives
Boon
+
22 kg
=200 L Hemp concrete
200 L
Mortar to be determined 110 kg/m3
220 kg/m3
Density
λ = 0,06 W/m.k
Thermal conductivity
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Hemp concrete
Thanks for your attention
Alexandre.gacoin@univ-reims.fr
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