|Title of Invention||
NEW HEMP CONCRETES AND MORTARS, THEIR PREPARATION PROCESS AND APPLICATIONS
|Abstract||ABSTRACT The invention relates to hemp mortars or concretes, i.e. with one or more hemp components in their formulation, in which the binder is at least partly made up of so-called « hydrated » lime, namely calcic lime in various forms such as a putty, powder or, for quick lime, the rock itself. The invention therefore relates to new formulations for hemp concretes and mortars wherein the binder is made up, in total or in part, of hydrated lime and wherein they furthermore include a) at least one admixture forming a « microcapillary system » of pores, tubes, volumes and very fine capillaries and b) at least one matrix water repellency admixture. FIG 3|
|Full Text||FORM 2
THE PATENT ACT 1970 (39 of 1970)
The Patents Rules, 2 003 COMPLETE SPECIFICATION
See Section 10, and rule 13)
1. TITLE OF INVENTION
A PROCESS OF MAKING HEMP CONCRETES AND MORTARS THEIR PREPARATION PROCESS AND APPLICATIONS
a) Name : BCB
b) Nationality : FRENCH Company
c) Address : RUE CHOUMOIS, ZAC DE VALENTIN,
F-25870 CHATILLON LE DUC, FRANCE
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -
New hemp concretes and mortars, their preparation process and applications.
Technical field of the invention :
5 This invention relates to the technical field of so-called «hemp» concretes and mortars i.e. containing hemp « chaff» or peeled stalk and/or other hemp components, such as fibres, fibrils, dust, hemp powder, hereinafter referred to as « components ».
These mortars and concretes are meant for all building and public works
10 applications as well as all household or other usual applications for concretes and mortars.
it is reminded that a mortar is made up of a mixture of binders such as lime, cement or the suchlike and aggregate(s) such as sand, stone powder, crushed marble and the suchlike, with water. Such a mortar is
15 used in building to bind and/or cover construction elements.
It is reminded that concrete is an artificial conglomerate of stone, gravel and sand, combined by means of an aqueous or non-aqueous binder.
Technical problem faced:
Incorporating hemp derivatives into a concrete or mortar poses a very
20 serious problem due to the highly hydrophilic aspect of the « hemp »
component. This can absorb up to approximately 400 % of its weight in
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water or aqueous based liquid which introduces a very strong reaction
competitive with the water contained in the mortar or concrete.
As will be seen below, various techniques to overcome this serious disadvantage have been attempted in the prior art, however one has not
5 been able to prevent the concretes or mortars obtained from having seriously random drying, setting characteristics and mechanical properties which is not acceptance in such a domain, these disadvantages can include: setting difficulties, possibly « broken » setting, no drying of concrete, or random drying, and/or poor or random mechanical properties,
10 and/or risk of taking in water from the outside (rainwater for instance) with the development of microorganisms, mould, brittleness on frost, etc...
Hemp mortars or concretes have been known for a very long time and even since olden times, where the hemp component (namely the
15 « chaff») is used as an aggregate, in all or in part, in the preparations. Similarly the preparation tooling is universally known as well as the suppliers of the current products and the most modern groups of products.
The binders used are usually plaster, lime (therefore used as hydraulic binder) and cements, i.e. hydraulic binders.
20 These products have the advantage of very good thermal and acoustic insulation, combined with very good mechanical resistance including a valuable component in terms of compressive strength and elastic recovery, making it a very good product adapted to the seismic standards.
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These products are used in hemp bricks, tiles, walls, blocks, concretes
and mortars which are or less light, in all building, public works and
However, they do have serious faults that a large part of the industry
5 concerned has not managed to overcome, despite all its efforts. The industry concerned has therefore made do with the well known yet serious disadvantages such as the drying and similar faults.
There is therefore a great and acknowledged need for hemp concretes and mortars which no longer have these heavy, serious or even
10 redhibitory faults, whilst maintaining their other excellent properties.
There is a specific need in the renovation or rehabilitation of historical structures and old buildings, a field in which concretes and mortars with hydraulic binder leads to failures.
Summary of the invention :
15 The invention relates to hemp mortars or concretes, i.e. consisting of one or more hemp components in their formulation where the binder is at least partly made up of so-called "hydrated" lime, namely calcic lime.
As one knows, hydrated lime is a binder which sets in the air by capturing carbon dioxide, C02 after reducing in an aqueous phase and calcic lime
20 is a binder mainly containing calcium hydroxide, dolomitic lime containing a mix of calcium hydroxide and magnesium hydroxide.
Hydrated lime could be used in various forms such as a putty, a powder,
or for quicklime, the rock itself.
Any mixes of all types and all forms of hydrated lime could be used.
Persons skilled in the art will know how to envisage and adapt these various combinations according to the specific application involved, based on their general experience, from this description and simple routine tests,
5 if need be.
According to one preferential embodiment, the said binder is made up of 20 to 90%, preferably 50 to 80% in weight of hydrated lime and 20 to 40%, preferably 10 to 70% in weight of hydraulic binder such as a hydraulic lime or a cement and, if required, 5 to 10% in weight of binder
10 and/or pozzolanic filler(s) of the volcanic ash type, «trass » (which is a volcanic rock well known by the person skilled in the art) or any other pozzolanic type component, the total being equal to 100 %.
Compared to the usual binders, plaster and cements used for decades, lime has quite substantial and specific special features and requirements.
15 Firstly, the lime particles are very fine and result in a specific surface area (Blaine) much greater than that of hydraulic binders.
Although known to a person skilled in the art, it is to be specified that the specific surface area (Blaine) of lime is approximately 8000 to 20,000, compared to approximately 2700 to 5000 for hydraulic binders.
20 Its setting characteristics are also radically different: whereas cements and plasters contain silicates, aluminates and/or sulphates, which intervene in the setting by way of a crystallisation phenomenon, lime intervenes in the setting by way of a recarbonation reaction where the calcium hydroxide undergoes a series of reductions with the water or the
aqueous based fluid of the concrete or mortar. In the case of lime, the water intervenes as a simple vector of the C02 required.
Furthermore, its solubility in water is only 1.7 g/l at 10 - 20 °C.
A particular problem related to the use of lime, and one that was
5 foreseeable due to the difficulty of correctly managing the water of the formulation which is what undoubtedly prevented it from being used in the prior art, was the difficulty in obtaining homogeneous behaviour and namely good rheology.
Another presumption against the use of hydrated lime was due to the fact
10 of believing that hydrated lime could not work in a concrete or mortar without being close to air, by definition, i.e. on the surface or over maximum depths of approximately 1 to 3 cm. However, the invention proposes a solution which, contrary to all expectations, does away with this problem.
15 A too long through drying time could also be reasonably feared. See figure 1A appended which shows that this fear was fully justified.
The invention has managed to overcome these presumptions and the significant prior problems thanks to a special formulation which incorporates special, pioneering porosity and capillarity characteristics. In
20 the prior art, some of the many problems faced had already been overcome, for instance caking, however never within the scope of the use of the hemp component, which represents a completely pioneering functional approach, as specified below.
Detailed description of the invention :
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The invention therefore relates to new formulations for «hemp»
concretes and mortars, i.e. including at least one « component » (in the
broad sense above) of hemp and/or flax and/or cereal straw such as oat pod or rice pod and/or in general any comparable hydrophilic material,
5 including synthetic, if required, individually or in mix(es), hereinafter for simplicity, including in the claims, « hemp ».
The invention therefore relates to new formulations for «hemp» concretes and mortars, i.e. consisting of at least one hemp component as specified above, and the technically equivalent components which include
10 the conventional ingredients of mortars and concretes, except wherein the binder is made up, in all or in part, of hydrated lime if required in various combinations of lime types and forms as indicated above, and wherein they furthermore include
a) at least one very fine pore and capillary forming admixture 15 and
b) at least one matrix water repellency admixture.
« Matrix water repellency », means here that the mass which covers the fibres and particles, etc., of hemp, undergoes the water repellent action of the admixture.
20 It will be noted that the hemp also undergoes this action, without, however, this having an impact as the hemp takes in water and is not water repelled as long as it contains water. Alternatively, after elimination of the water contained in the hemp, the water repelling action comes into play and the hemp no longer takes in water, for example, it does not take
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in humidity or rainwater, etc...., which is one of the major advantages of
« Formation of very fine pores and capillaries », refers to here as the formation of a very complex assembly, the structure of which may vary
5 from one formulation to another, but which consists of open and/or closed capillary tubes as well as microbubbles or closed microspaces and/or closed microcavitations, amongst which closed tubes, arranged, proportioned and distributed so that the final concrete or mortar has homogeneous or substantially homogeneous characteristics and no
10 longer has setting or drying faults or random properties, i.e. arranged, proportioned and distributed such that the matrix water can be evacuated to the surface on setting then drying whereas, after drying, external water (rain) is no longer capable of penetrating into this capillary network.
This complex assembly will be described hereinafter, including the claims 15 as a « microcapillary system » for reading simplicity.
Persons skilled in the art who are well aware of the setting and drying problems with hydraulic concretes and mortars and the characteristics to be obtained in order to form a « good » concrete or mortar, and who are furthermore also aware of the difficulties and disadvantages of hemp
20 mortars and concretes, will have no difficulty in adjusting the microcapillary system of the invention, namely according to the % of hydrated lime, on reading the description and examples hereinafter and from their personal experience and by way of a few routine tests, if required, with a view to adaptation to the specific application envisaged.
25 According to a preferential embodiment, the microcapiitary system forming admixture includes one or more vegetable and/or mineral colloids.
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According to yet another preferential embodiment, the microcapillary
system forming admixture is adapted to result in capillarity of
approximately 5 to 15 Angtroms, preferably 8 to 10 Angstroms.
As a comparison, hemp or flax has capillarity which is approximately 3 to
5 5 times greater and a hydraulic binder gives capillary of approximately 10 to 20 times greater.
According to yet another preferential embodiment, the said microcapillary system forming admixture is adapted so that the said microcapillary system has closed tubes and/or volumes and/or spaces and/or
10 microbubbles and/or microcavitations, namely closed tubes.
Without wanting to be related to any theory, the Applicant considers that such spaces, namely closed tubes are capable (combined, if required, with open microcapillaries) of extracting the water contained in the hemp and enabling it to migrate to the surface, gradually, in the form of liquid
15 water then vapour, which is finally diffused to the outside.
According to yet another, non-restrictive preferential embodiment, the colloids are chosen from vegetable colloids such as alginates and/or polysaccharides and all natural or synthetic starch derivatives and/or carrageens.
20 Hydroxypropyl guar (polysaccharide family) which has given the best results will namely be quoted here.
Good results were also obtained with carrageens (which are products similar to alginates) and calcium alginate.
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Alternatively, sodium and magnesium alginates tend to precipitate and are not recommended.
Other microcapillary system forming admixtures will be chosen from the following:
5 - etherified galactomannan and
etherified guar derivatives
and mixes of them.
According to a preferential embodiment, the said water repellency admixture consists of at least one water repellent agent and one surface
10 active or tensio-active agent.
Without wishing to be related to any theory, the Applicant considers that tie surface active agent provides a « net» or « mesh » type structure which strongly contributes to the homogeneity of the final product and its properties.
15 According to one alternative embodiment, one surface active agent is used as a neutral or basic medium and/or one surface active agent as an acid medium and/or suitable mixes of them, according to the foreseeable change in pH (which any person skilled in the art knows and knows how to assess).
20 According to a non-restrictive, preferential embodiment, the surface agent(s) will be chosen from calcium, sodium or magnesium polysulphonates, lignosulphonates in particular.
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According to yet another non-restrictive, preferential embodiment, other surface active agent(s) will be chosen from the following:
According to a preferential embodiment, the water repellent agentsare
5 preferably chosen from metallic soaps, maleates, oleates, stearates, and the suchlike, of aluminium, magnesium, sodium, lithium and analogue salts and/or sodium siliconates and other mixes of them.
According to a non-restrictive, preferential embodiment, the water repellent agents will be chosen from the following:
10 - sodium oleates.
According to a non-restrictive, preferential embodiment, the admixtures and agents used according to the invention will be used in the following proportions:
a) microcapillary system forming admixture:
15 from 0.01 to 2 % with respect to the total mass of binder
b) water repellency admixture:
from 0.1 to 1 % with respect to the total mass of the binder surface active agent
from 0.002 to 0.2 % with respect to the total mass of the binder
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Thus a new industrial product is obtained wherein it consists of mortars
and concretes with a hemp component and binder including hydrated lime, including
a) at least one very fine pore and capillary forming admixture
b) at least one water repellency admixture and
of which the setting, the mechanical characteristics and the drying are not random.
The invention also relates to a new industrial product of the mortars and
10 concretes type with hemp component and binder including hydraulic lime wherein its mass includes a microcapillary system which itself includes tubes and/or volumes and/or microbubbles and/or closed microcavitation(s), namely closed tubes, capable, namely the closed tubes (combined with open microcapillaries if required) of extracting t
15 water previously absorbed and contained in the hemp and enabling it to migrate to the surface, gradually, in the form of liquid water then vapour, which is finally diffused to the outside, until it dries.
This product is also characterised in that its water repellent matrix makes the dry hemp component fibres water repellent, thereby preventing water
20 from being taken back in by the hemp component.
According to another alternative form, this product is characterised in that its global (or «residual») lambda thermal conductivity coefficient is approximately 0.08 to 0.12, preferably around 0.1.
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As a comparison, the thermal conductivity coefficient of a hydraulic concrete or mortar is approximately 0.6 to 1.15, i.e. approximately five to eleven times higher.
Such products will all be used in the building and publics works field as
5 concrete blocks, blocks of various sizes and shapes, bricks and the suchlike well known by persons skilled in the art, hereinafter referred for simplicity as « concrete blocks », as well as plates, coatings, wall, floor, ceiling coverings, etc., and the suchlike well known to persons skilled in the art.
10 Other characteristics and advantages of the invention will be better understood on reading the description which follows and by referring to the drawing enclosed on which:
figure 1 which is comprised of figures 1A (left) and 1B (right) represents a photograph of two samples ( 20 X 30 X 60 cm) of hemp
on the left-hand figure (1A): concrete excluded from the invention (comparative test) made with a mixture of plaster and hydrated lime (white area of drying which is too long and development of mould)
on the right-hand figure (1B): concrete made with a mix 20 according to the invention
figure 2 represents a scanning electronic microscope photograph of a lime mortar on a hemp aggregate ( x 1000). The liaison between the hemp (A) and the lime (B) is made duly apparent. The grains of lime house themselves inside the fibrous channels of the plant
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figure 3 represents a scanning electronic microscope photograph
showing air bubbles and microbubbles and tubular channel orifices in the
lime putty (x 111). The porosity of the lime putty is made up of air bubbles
and tubular channels which are formed after evaporation of the mixing
figure 4 represent a scanning electronic microscope photograph
showing a network of air bubbles and tubular channels ( x 17). The
complete covering performed according to the invention, amalgam of
tubes, closed tubes (some of which are visible as they were cut), spaces
10 or volumes, capillaries and hemp chips are clearly apparent.
figure 5 represents a comparative hemp structure WITHOUT the lime component.
The microscopic examination (figures 2 to 5) allows for the presence, according to the invention, of a large capillary network comprised of air
15 bubbles and tubular channels, to be made apparent.
EXAMPLES Example 1
For 1 m3 of hemp:
220 kg of binder, of which:
30 a 35% in weight of natural hydraulic lime or the like
1 a 2% of an additive system as defined above.
The characteristics for this kind of product are : density: 0.32
thermal conductivity: 0.09 W/m.K
5 compressive strength (90 days): 0.9 MPa. Steam permeance: 0.743 g/m2.h.mmHg
10 Insulating concrete/mortar layer: For 1 m3 of hemp:
275 kg of binder of which:
15 25 a 35% in weight of natural hydraulic lime or the like
50 a 65% of hydrated lime of the type CL90S or DL 85 S1 1 a 2% of an additive system as defined above 10% of mineral filler
20 The characteristics of this kind of product are : density: 0.375
thermal conductivity: 0.11 W/m.K compressive strength (90 days): 1.1 MPa.
25 The invention relates to formulations for « hemp » concretes and mortars with a binder including lime as well as new industrial products consisting of these mortars and concretes, as well as the use of the microcapillary system forming admixture and/or the water repellency admixture as
admixtures for « hemp » mortars and concretes, as well as the products
made using these mortars and concretes or formulations, or using the microcapillary system forming admixture and/or the water repellency admixture, such as bricks, blocks, concrete blocks, various « hemp »
5 elements, as well as the products for the building and public works field, or individual constructions, made using these mortars or concretes, admixtures or products, such as walls, tiles, slabs, coverings and coatings for floors, ceilings, walls, partitions and similar structures.
The invention also covers all the embodiments and all the applications
10 which will be directly accessible to persons skilled in the art on reading this application from their own experience and where appropriate from simple routine tests.
1. New industrial product wherein it consists of mortars and concretes
with a hemp component and binder including hydrated lime wherein it includes:
a) at least one very fine pore and capillary forming admixture called «
microcapillary system »
b) at least one water repellency admixture,
wherein the setting, the mechanical characteristics and the dying are not random.
2. New industrial product according to claim 1 wherein it includes a « microcapillary system » in its mass which includes closed tubes and/or
volumes and/or spaces and/or microbubbles and or microcavitation(s), namely closed tubes, capable, namely the closed tubes (in combination with any open microcapillaries) of extracting the water previously absorbed and contained in the hemp and enabling it to migrate to the surface, gradually, in liquid then vapour form, which is finally diffused to the outside until it dries.
3. New industrial product according to claim 1 or 2 wherein its water
repellent matrix makes the dry hemp component fibres water repellent
thereby preventing water from being taken back in by the hemp component.
4. New industrial product according to any one of claims 1 to 3 wherein its global (or « residual ») lambda thermal conductivity coefficient is approximately 0.08 to 0.12, preferably around 0.1.
5. Applications of new industrial products according to any one of claims 1 to 4 to form hemp concretes and mortars, bricks, blocks, concrete blocks, wall elements, tiles, coatings, slabs and floor, ceiling, partition coverings, products for building and public works or individual constructions.
Dated this day of
Title : New hemp concretes and mortars,
their preparation process and applications.
Inventor: Mr. Michel RIZZA
Applicant: STRASSERVIL - EUROVENTE S.A.
The invention relates to hemp mortars or concretes, i.e. with one or more hemp components in their formulation, in which the binder is at least partly made up of so-called « hydrated » lime, namely calcic lime in various forms such as a putty, powder or, for quick lime, the rock itself.
The invention therefore relates to new formulations for hemp concretes and mortars wherein the binder is made up, in total or in part, of hydrated lime and wherein they furthermore include a) at least one admixture forming a « microcapillary system » of pores, tubes, volumes and very fine capillaries and b) at least one matrix water repellency admixture.
|Indian Patent Application Number||287/MUMNP/2005|
|PG Journal Number||13/2008|
|Date of Filing||15-Apr-2005|
|Name of Patentee||BCB|
|Applicant Address||RUE CHOUMOIS, ZAC DE VALENTIN F-25870 CHATILLON LE DUC, FRANCE|
|PCT International Classification Number||C04B28/10|
|PCT International Application Number||PCT/FR02/02123|
|PCT International Filing date||2002-06-19|