Additive of protein nature for hydraulic cements, mortars & concretes, and use thereof in the field construction

The present invention relates to a novel additive for hydraulic cements, mortars and concretes, particularly for improving the mechanical strengths and the workability and for reducing sweating and segregation, which is characterized in that it is a protein hydrolysate having a pH less than or equal to 6, comprising substances selected from the group constituted by proteins, polypeptides, aminoacids and mixtures thereof, and obtained by treating 100 volumes of an aqueous composition containing at least one protein substance selected from the group constituted by proteins, polypeptides and mixtures thereof, with at least one bacterial strain producing lactic acid having a population greater than or equal to 10.sup.2 germs/cm.sup.3, in the presence of 0.5 to 30 parts by weight of a source of carbon belonging to the family of carbohydrates, for at least 2 hours, at a temperature of between 0.degree. and 65.degree. C. and at a pH less than or equal to 6.

The present invention relates to a novel additive of protein nature, for 
hydraulic cements, mortars and concretes. It also relates to the use of 
this additive in the field of construction. 
The expression "protein substance" or "substance of protein nature" is 
understood in the following specification to mean any product belonging to 
the group constituted by proteins, polypeptides and mixtures thereof; and 
the expression "protein hydrolysate" is understood to mean any product 
belonging to the group constituted by proteins, polypeptides, aminoacids 
and mixtures thereof. 
It has already been recommended to use proteins in the building field, 
particularly for making cellular concretes and light colloidal concretes. 
According to the indications given in KEITEL's work "Zement: Herstellung 
und Eigenschaften", Springer-Verlag Berlin-Heidelberg-New York 1971, page 
186, lines 38-40, it is thought that the ancient Romans used animal blood 
in the manufacture of porous concrete. However, the use of proteins raises 
difficulties in the building field by inducing delays in setting, as 
indicated by JOISEL in "Adjuvant du ciment", Editions Star, Paris 1965, 
pages 45 and 105. 
Furthermore, it is known from U.S. Pat. No. 4,203,674, which recommends 
using blood in powder form as air-entraining colloid in association with 
another colloid (in particular hydroxyethylcellulose, 
hydroxypropylmethylcellulose and carboxymethylcellulose) to obtain 
lightened concretes and mortars, that liquid blood is not suitable for 
making said lightened concretes and mortars. 
The invention recommends a novel technical solution for improving the 
mechanical strengths (particularly the tensile, bending and compressive 
strengths), for reducing sweating and segregation, and finally for 
improving the workability of the hydraulic cements, concretes and mortars. 
This novel technical solution which favourably modifies a certain number 
of rheological parameters, employs liquid protein hydrolysates which 
differ from the additives heretofore known in the building domain. 
The protein additive recommended according to the invention for improving 
the mechanical properties, the workability and for reducing sweating and 
segregation of the hydraulic cements, concretes and mortars, is 
characterized in that it is a protein hydrolysate having a pH less than or 
equal to 6, comprising substances selected from the group constituted by 
proteins, polypeptides, aminoacids and mixtures thereof, and obtained by 
treating 100 parts by weight of an aqueous composition containing at least 
one protein substance selected from the group constituted by proteins, 
polypeptides and mixtures thereof, with at least one bacterial strain 
producing lactic acid having a population greater than or equal to 
10.sup.2 germs/cm.sup.3, in the presence of 0.5 to 30 parts by weight of a 
source of carbon belonging to the family of carbohydrates, for at least 2 
hours, at a temperature of between 0 and 65.degree. C. and at a pH less 
than or equal to 6. 
The protein hydrolysate useful according to the invention in the 
construction domain may be used directly in the liquid or humid state. 
Before being associated with a hydraulic cement and with water, or as the 
case may be, with a hydraulic cement, water with sand and/or granulates, 
it may be conserved in a suitable recipient for at least 18 months at a 
temperature of between -5.degree. and +60.degree. C. 
The protein additive according to the invention differs, by the mode by 
which it is obtained, from the means recommended by German Pat. No. 511 
513 on the one hand and the summary of Chemical Abstracts 88, 140 835 t, 
on the other hand. 
Among suitable protein hydrolysates, particular mention may be made of 
those obtained from animal or plant proteins. Among these proteins, 
mention may be made of proteins of animal origin such as meat product 
proteins, offal product proteins, milk proteins, whole fish proteins, fish 
wastes, albumins (particularly egg albumin), and plant proteins such as 
those contained in the Leguminosae, oleaginous plants, Solanaceae 
(particularly tobacco) and algae. 
Protein substances which are suitable for obtaining the hydrolysate 
according to the invention are in particular the animal and plant proteins 
mentioned above as well as the hydrolysates and proteolysates of said 
animal and plant proteins which comprise, in particular, either proteins 
which have not yet broken down, or polypeptides, or mixtures of proteins 
an polypeptides, in association, as the case may be, with aminoacids. 
The ground meat product proteins or the ground or liquid offal product 
proteins are advantageously rapidly subjected to treatment with bacteria 
producing lactic acid. Before such treatment, especially if it is delayed, 
it is recommended to associate with the protein substances 1 to 15% by 
weight of crushed cereals. 
The following bacteria producing lactic acid may be used in the preparation 
of the hydrolysate useful according to the invention as additive in the 
construction domain: Streptococcus (particularly Streptococcus bovis, 
Streptococcus thermophilus, Streptococcus faecalis, Streptococcus faecium, 
Streptococcus cremoris, Streptococcus lactis), Leuconostoc (particularly 
Leuconostoc mesenteroides, Leuconostoc lactis, Leuconostoc cremoris) and 
Lactobacillus (particularly Lactobacillus delbrueckii, Lactobacillus 
leichmanii, Lactobacillus jensenii, Lactobacillus lactis, Lactobacillus 
bulgaricus, Lactobacillus helveticus, Lactobacillus acidophilus, 
Lactobacillus casei, Lactobacillus plantarum). Among suitable strains, 
particular mention may be made of the strains of the Collection of the 
Pasteur Institute: Streptococcus bovis 56.23, Streptococcus thermophilus 
66.31, Streptococcus faecalis 54.32, Streptococcus faecium 54.31, 
Streptococcus lactis 70.57, Leuconostoc mesenteroides 53.49, Lactobacillus 
delbrueckii 57.8, Lactobacillus leichmanii 53.61, 53.3 and 53.4, 
Lactobacillus jensenii 69.17, Lactobacillus bulgaricus 71.36, 
Lactobacillus helveticus 57.15, Lactobacillus acidophilus 76.13 and 71.34, 
Lactobacillus casei 71.37, 71.38 and A 158, Lactobacillus plantarum 71.39, 
and the strain of the catalogue of the American Type Culture Collection: 
Lactobacillus lactis ATCC 8000. 
According to the invention, one or more strains of lactic acid-producing 
bacteria will be used. The bacterial population will be between 10.sup.2 
germs/cm.sup.3 and 10.sup.8 germs/cm.sup.3, and advantageously between 
10.sup.3 germs/cm.sup.3 and 10.sup.6 germs/cm.sup.3. 
The total content of protein substance and aminoacid contained in the 
liquid protein hydrolysate according to the invention is between 0.5 and 
50% weight/volume. If necessary, the protein hydrolysate may be 
concentrated in vacuo and/or sterilized. 
The carbohydrates used as source of carbon may be hydrolyzable or 
non-hydrolyzable, the preferred carbohydrates being in particular glucose, 
lactose, saccharose, maltose, water-soluble starch and whey. 
It is possible to select the or each bacterial strain which may be used 
according to the invention by referring on the one hand to the intrinsic 
stability of the liquid protein hydrolysate obtained and on the other hand 
to a test of use which may be described as follows: 
Two concretes A and B, of the following composition, are made: 
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A B 
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cement of CP5 45 type 400 g 400 g 
with fillers 
lime, type HA 40 g 40 g 
light granulate 2 l 2 l 
(polystyrene, 1 to 5 mm diameter) 
0 22 g 
additive 
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The role of the additive according to the invention added to concrete B 
will be a densification of said concrete equivalent to at least 10 per 
cent of entrained air. 
According to the invention, a process for manufacturing a construction 
element from a hydraulic cement, water and a liquid protein additive is 
recommended, whereby 100 parts by weight of hydraulic cement are mixed 
with 0.001 to 10 parts by weight of liquid protein additive previously 
diluted with mixing water. 20 to 50 parts by weight of mixing water for 
100 parts by weight of hydraulic cement will advantageously be used. 
According to this process, sand and/or granulates, which may be light and 
possibly expanded (polystyrene balls, glass balls, mica, vermiculite) or 
heavy depending on the desired density of the construction material, may 
also be introduced. 
Four types of material may be obtained by the process of the invention, 
namely: 
material A, from 
100 parts by weight of hydraulic cement, and 
0.001 to 10 parts by weight of protein additive; 
material B, from 
100 parts by weight of hydraulic cement, 
0.001 to 10 parts by weight of protein additive, and 
1 to 9000 parts by weight of sand; 
material C, from 
100 parts by weight of hydraulic cement, 
0.001 to 10 parts by weight of protein additive, and 
1 to 90000 parts by weight of granulates; and 
material D, from 
100 parts by weight of hydraulic cement, 
0.001 to 10 parts by weight of protein additive, 
1 to 9000 parts by weight of sand, and 
11 to 90000 parts by weight of granulates. 
The best embodiment of the invention consists, to obtain a construction 
material, in mixing 100 parts by weight of hydraulic cement (particularly 
cement or blast furnace slag) with 0.001 to 10 parts by weight of protein 
additive previously diluted in, preferably, 30 to 35 parts by weight of 
water with, as the case may be, sand and/or light or heavy granulates, the 
protein additive being obtained from liquid animal blood which is one of 
the elements of offal. The fresh animal blood which is collected at the 
abattoir must have an anti-coagulant added thereto (particularly an 
anti-coagulant selected from the group constituted by the alkali metal 
citrates, polyphosphates, heparin and silicones) within the five minutes 
following bleeding. 0.05 to 1 part by dry weight of anti-coagulant will 
advantageously be incorporated with 100 parts by weight of fresh liquid 
blood, treatment with the bacteria producing lactic acid being carried out 
at the latest 6 hours after bleeding. 
It is unnecessary to employ a particular mixer as indicated in U.S. Pat. 
No. 4,203,674 mentioned above, the cement is mixed with mixing water 
containing the protein additive, then, as the case may be, sand and/or 
granulates, in a conventional mixer operating at 50-100 rpm.

Other advantages and features of the invention will be more readily 
understood on reading the following description of embodiments which are 
in no way limiting but given by way of illustration. 
EXAMPLE 1 
Concrete incorporating light granulates 
A concrete is prepared from the following ingredients: 
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hydraulic cement 250 parts by weight 
sand having particles with a 
50 parts by weight 
diameter smaller than or equal to 0.8 mm 
light granulates 10 parts by weight 
(polystyrene balls) 
liquid protein additive (hydrolysate 
10 parts by weight 
of beef blood having a total content 
of proteins, polypeptides and aminoacids 
included between 15 and 20% 
weight/volume) 
mixing water 80 parts by weight 
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The cement is homogenized (30 minutes), the mixing water containing the 
protein additive (30 seconds), the sand and the granulates are added, then 
mixed for 60 to 120 seconds in a mixer operating from 100 to 60 rpm. 
The concrete thus obtained may then be compacted, vibrated, then 
immediately removed from the mould to obtain prefabricated articles, or 
directly positioned after pumping, cold extrusion or projection on site. 
After conservation in a damp atmosphere (100% RH) at 20.degree. C. for 7 
days, this concrete presents an apparent density (MVA) of 400 kg/m.sup.3, 
and (according to the measurements made on test pieces measuring 28 cm 
.times.7 cm .times.7 cm) a tensile-bending strength (TF) of 
7.times.10.sup.5 at 10.sup.6 pascals and a compressive strength (RC) of 
1.4.times.10.sup.6 at 2.5.times.10.sup.6 pascals. 
By comparison, the concrete obtained by replacing the 10 parts by weight of 
protein additive by 10 parts by weight of water, gives, under the same 
conditions: 
MVA:350 kg/m.sup.3 
TF:5.times.10.sup.4 at 2.times.10.sup.5 pascals 
RC:2.times.10.sup.5 at 4.times.10.sup.5 pascals. 
EXAMPLE 2 
Concrete incorporating heavy granulates 
A concrete is obtained by proceeding as indicated in Example 1, from the 
following ingredients: 
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hydraulic cement 260 parts by weight 
gravel (having particles with a 
1400 parts by weight 
diameter of between 3 and 8 mm) 
sand 50 parts by weight 
liquid protein additive (hydrolysate 
10 parts by weight 
of beef blood having a total content of 
proteins, polypeptides and 
aminoacids of 15 to 20% weight/volume) 
water 80 parts by weight 
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This concrete, after conservation in a humid atmosphere (100% RH) at 
20.degree. C. for 7 days, as indicated in Example 1, presents the 
following properties: 
MVA:1800 kg/m.sup.3 
TF:2.3.times.10.sup.6 pascals 
RC:9.7.times.10.sup.6 pascals 
On the other hand, the product obtained by replacing the 10 parts by weight 
of protein additive by 10 parts by weight of water presents, under the 
same conditions, the following properties: 
MVA:1800 kg/m.sup.3 
TF:1.6.times.10.sup.6 pascals 
RC:7.8.times.10.sup.6 pascals. 
The tests carried out with the construction materials obtained according to 
the invention with the protein additive coming from blood or another 
source of protein show that said additive possesses a thickening power, a 
gelling power and an emulsifying power. 
As far as the thickening power is concerned, it is observed that the 
protein additive according to the invention is capable of binding a 
certain quantity of water with a force which is the greater as it is in 
intimate association therewitih. This capacity to retain water brings 
about an expansion of the molecules of the protein additive, at the origin 
of an increase in the viscosity. 
As far as the gelling power is concerned, it is observed that the protein 
additive, under the effect of setting of the hydraulic cements, forms a 
three-dimensional matrix containing in its meshes the components of the 
construction material. 
Concerning the emulsifying power, a lowering of the interfacial tension 
which exists between two non-miscible faces such as fat and water, is 
observed. The macromolecules and the protein additive presenting a 
lipophilic pole and a hydrophilic pole are placed essentially at the 
interfaces of the drops. The hydrophilic pole in the water and the 
lipophilic pole in the fat group together to form air bubbles. This 
results in a rearranement which reduces or eliminates the interfacial 
tension. 
The construction materials according to the invention are useful in 
particular in the manufacture of numerous articles of construction. The 
light concrete of Example 1 is particularly advantageous in the 
manufacture of bridge floors, it makes it possible to decrease the weight 
of the metallic structure, to ensure a better distribution of the 
overloads and, due to its insulating properties, to limit conduction of 
vibrations. 
In the domain of highways and motorways, the concrete of Example 1 makes it 
possible simultaneously (i) to ensure good protection with respect to the 
frost/thaw cycles, and (ii) to reduce the depth of the foundations. 
According to conventional techniques, a highway with dense traffic 
comprises, from top to bottom: 
a layer of surfacing of 5 cm, 
a bituminous layer of 18.5 cm, 
a supporting layer of rolled granulates of 15 cm, 
an aerated layer for protection against frost of 45 cm, and 
a so-called foundation layer of 20 cm. 
With the concrete of Example 1, the total thickness has advantageously been 
reduced by replacing the supporting layer of rolled granulates and the 
frost-protection layer by one single layer of concrete of 22 cm, whilst 
giving the same protection with respect to the frost/thaw cycles. 
The concretes according to the invention are also useful in the preparation 
of hollow gauged bricks, noggings, roof slabs, prefabricated partitions 
and smoke flues. 
By way of information, a mode of preparing the hydrolysate (stabilized 
protein) which may be used according to the invention will be described 
hereinafter: 
100 liters of beef blood (collected from healthy animals) have 600 g of 
sodium citrate (anti-coagulant) added thereto within the 5 minutes 
following bleeding. This blood is then treated (within the 3 hours 
following bleeding) with lactic acid-producing bacteria (mixture of 
Streptococcus lactis, Leuconostoc mesenteroides and Lactobacillus casei) 
so that the bacterial population in the resulting medium is at least 
10.sup.5 germs/cm.sup.3, and 10 kg of carbohydrate (water-soluble starch), 
for 24 hours at 28.degree. C., the pH of the resultant medium always being 
less than 6 (as lactic acid is formed, the pH stabilizes at about 4.7). 
Analysis of this hydrolysate conserved for 15 months, at a temperature of 
between 15 and 20.degree. C. and at a pH of about 4.7, gives the following 
results shown in Table I hereinafter with a total content of aminated 
nitrogen of 2.58%. 
TABLE I 
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Composition in g/per 100 g 
Components of protein hydrolysate 
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Aspartic acid 2.22 
Threonine 1.08 
Serine 1.13 
Glutamic acid 2.01 
Proline 0.839 
Glycine 0.978 
Alanine 1.67 
Valine 1.78 
Cystine 0.313 
Methionine 0.309 
Isoleucine 0.196 
Leucine 2.30 
tyrosine 0.635 
Phenylalanine 1.36 
Lysine 1.91 
Histidine 1.20 
Arginine 0.767 
Tryptophane 0.279 
NH.sub.3 after hydrolysis (6 N HCl) 
0.114 
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