WO2015063528A1

WO2015063528A1 - Procedure for the preparation of cementitious cellulose-containing concrete products with reduced water absorption properties, and use of the concrete products obtained

Info

Publication number: WO2015063528A1
Application number: PCT/HU2014/000093
Authority: WO
Inventors: Viktor CSÓKAI
Original assignee: Molnárbeton Betongyártó És Kereskedelmi Kft.
Priority date: 2013-10-29
Filing date: 2014-10-14
Publication date: 2015-05-07
Also published as: HU230624B1; HUP1300617A2

Abstract

The invention relates to the procedure for the preparation of cementitious cellulose-containing concrete products with reduced water uptake properties, with the use of a component of high cellulose-content. According to the method of the invention the cellulose-containing component, cement, water and optionally a homogenized mixture containing known additives are suspended before curing with 1-20 wt% vegetable oil by weight of the mixture, as a step of manufacturing the concrete product.

Description

Procedure for the preparation of cementitious cellulose-containing concrete products with reduced water absorption properties, and use of the concrete products obtained

The invention relates to the procedure for the preparation of cementitious concrete products containing cellulose with reduced water uptake properties, and use of the concrete products obtained.

In the description the expression "cellulose" means primarily, but not exclusively paper originating from waste sources, aqueous mass containing paper fibres, so-called paper sludge, and other wastes associated with paper, like paper- plastic or paper-plastic-aluminium packaging materials, industrial by-products, die cutting waste, wastes of spoilage products; but it was found that the wood, reed, agricultural wastes with high cellulose content (straw, hay, corn stalk, corn cob, corn leaf and dry corn-husk, sunflower stem, sunflower leaf, sunflower plate, seed- coat, etc.) can also be used for the purpose of the invention. Therefore these, and a mixture thereof can also be present in the waste to be processed as ..cellulose".

In the wording of the invention the expression "concrete product" homogenized concrete products containing the components in appropriate amounts is meant.

It is known that in the past decades the need for fossil energy carriers, or the amount of the energy used for heating is increasing year by year. In parallel with this the growing population - primarily the so-called consumer societies - generate the rocketing quantitative use of the amount of the packaging materials, and together with this the paper, as packaging material. The population growth needs to improve the efficiency of crop production also, and with this the amount of the dry agricultural wastes with high fibre and cellulose content is also increasing. For the above reasons, in the past decades there has been a growing interest globally for the solutions of the above type relating to the use of the cellulose wastes or cellulose-containing wastes. The construction industry emerged as a possible technical field considered as a future large-scale utilization, because in this field there is a need for the generation of an economical, stable construction material with good thermal insulation capacity, which, in addition to its economical nature makes the environment-friendly use of the cellulose-containing wastes became unnecessary in the construction industry.

Considering that the above problem is a real and pressing, several documents have been generated in the technical literature dealing with its possible solutions, most of them is dealing with the preparation and use of the paper concrete (in the English technical literature papercrete).

Thus the US Patent No.5,482, 550 is describing an experimentally elaborated material of rather complicate composition, which includes polystyrene foamed (1-25% wt%), paper fibre (1-35 wt%), cement (30-75 wt%), ash (2-15 wt%), superfine silicon-dioxide (1-10 wt%), bentonite (1-15 wt%), water (25-50 wt%), and air, paraffin oil emulsion (0-10 wt%) and rubber emulsion (0-15 wt%). The water repellent character reached with the relatively high amount of water excluding materials can be attributed primarily to the polystyrene, the paraffin and the rubber emulsion.

According to US Patent No. 5,817,262 a material composition of wood- gypsum mixture with increased water repellent characteristics is described, the water repellent characteristics of which has been reached by the addition of siloxane.

In US Patent description No. 2006/0022373 an equipment is described, which can prepare lightweight concrete from agricultural wastes by the addition of a cement mass prepared in advance, without the specification of the mixing ratios, additives, and the characteristics of the finished product.

According to US Patent description No. 2008/0282632 instead of the modification of their composition, the protection of the concrete elements against weather is solved by building compositions, by covering the built-in surfaces. In US Patent description No. 2009/0065978 the manufacturing technology of a mixture of materials is described, which consists of water, paper, calcium stearate and sodium silicate, reinforced with cement. A polyester-polyacrylate- polyol mixture is added to this mixture as fluxing agent, which makes the paper- containing mixture extrudable, agitable and mouldable as construction material. In order to protect it against the influences polyurethane or polycarbamide coating is recommended.

For the paper industry pure cellulose fibre material is prepared with alkaline treatment of wastes, raw materials of high cellulose content. Such a solution is described in process patent description No. HU 214933, according to which cellulose fibres are prepared with high efficiency with mechanical and chemical (at very high pH value, in the presence of alkaline bases or milk of lime) treatment, in order to reach a dry matter content as high as possible, and to leach out the shorter chain cellulose oligomers. Further use of this cellulose fibre material is envisioned in the paper industry.

Regarding the entirety of the solutions referred above it can be said that the introduced technologies, procedures, or the product itself provides a cheap, lightweight masonry material with good thermal insulation capacity, but very sensitive to water. They swell, crack, and even freeze both by the effect of vapours and the environmental precipitations.

Each of the solutions mentioned above relates to cement enforced mixture of materials, part of which contain paper, or another cellulose-containing fibre material, and another part deals with doping, and surface modification of the finished product (floor, wall, etc.). There is no mixture of material known in the technical literature which would develop water repellent effect simultaneously, in the course of manufacturing, in such a way that essentially the other characteristics, like compressive and tensile strength, thermal and sound technical characteristics, or the vapour diffusion and flammability properties do not change.

Therefore the goal of this invention is to elaborate the utilization possibilities of the cellulose-containing wastes with which construction and insulation materials are provided simultaneously, in addition to the elimination of the disadvantages of the materials already published, mentioned above as prior art, i.e. simultaneously with manufacturing the concrete products keeping the static, vapour diffusion and insulation technology data, and with the maximization of the water repellent character.

Surprisingly it was found that our goals cannot be reached according to the known teachings with the addition of water repellent materials, but with the addition of vegetable oil to the mixture in the course of the manufacturing process. This solution is surprising even for the experts, because it is a well-known fact that the cellulose fibres, such as the paper regrind, agricultural wastes (corn stalk, corn cob, sunflower stem and sunflower plate) are capable of binding, absorbing the vegetable oils, even from the aqueous emulsions, this way facilitating the purification of waters contaminated with oil. In the event that the cellulose- containing material has already been soaked with apolar, hydrophobic (oily) derivatives, it is no longer wettable, therefore it cannot even be brought into cement bonding. Therefore in our case it is surprising that an aqueous suspension, for the curing of which the water is essential, is made water repellent with vegetable oils. It was found that the water repellent additives of the concrete industry are all known derivatives of triglycerides of vegetable or animal origin, with such an effect. But surprising, improved results were obtained, when, according to the invention discovery not the derivatives already prepared in advance were used, but the vegetable oils used for their manufacturing.

Therefore the object of the invention is a process for the preparation of cellulose-containing cementitious concrete products with reduced water absorbing characteristics, with the use of a component with high cellulose content, and the essence of the method is that cellulose-containing component, cement, water and optionally a homogenized mixture containing known additives are suspended with 1-20 wt% vegetable oil by weight of the mixture, as a step of manufacturing the concrete product.

Preferably cellulose powder, paper sludge, plastic reinforced paper, aluminium-paper-plastic combinations, vegetable wastes and residues, like husk and corn cob grist is used. It is also preferred if the cellulose based component is originating from waste materials.

Minced high paper-content materials are used as aluminium-paper combination.

According to the invention mostly sunflower oil, corn oil, rapeseed oil or used cooking oil is used as vegetable oil (otherwise the last one is a hazardous waste to be disposed).

The invention further relates to the application of the concrete product for the preparation of lightweight concrete.

The invention also relates to the use of the concrete products prepared according to the invention for the preparation of masonry units, thermal and/or sound insulation panels or floors.

When the solution according to the invention was elaborated, the cement binding possibilities of the paper and cellulose raw materials originating from a waste source was studied first. In the course of our experiments the wettability of the dry raw materials, their integrability into the cement technology was determined, and their comminution demand, and the mixing and additive demand, suitable for the different fields of application (higher compressive strength and lower bending strength and heat-insulation characteristic or vice versa).

Hereinafter - except where otherwise specified - in relation to amounts the %, ratio, portion expressions relate to mass.

Experiments were conducted, starting from the following raw materials: paper industry paper sludge, other paper sludge, cellulose powder, paper stripes reinforced with plastic fibres, ground aluminium-paper-plastic combination (soft drink and milk cartons), ground agricultural seed-coat, ground corn cob. Cement binding of the raw materials with different cellulose content was solved in a different way, depending on whether it has already contained water necessary for the cement curing, or not. Out below the components and ratios necessary for the preparation of the cellulose-containing concrete mixture are presented in relation to embodiments. It is illustrated in the examples that what compressive strength and water absorbency is provided by the mixture. The water uptake was measured with the addition of the additives, and without additives. As it can be seen from the following, water uptake was improved by the additives.

Example A

Paper sludge (cellulose-containing raw material)

Mixings with the paper sludge were carried out in the following component ratios:

Measurement of the compressive strength and the water uptake was carried out following a 28 days curing and drying period. The water uptake investigations were supplemented with a floating experiment. Each paper concrete cube was floating on the water, but in the course of the water uptake they started to sink. None of the sunken specimen fell apart, they kept they form, both their volume and shape. Example B

Cellulose powder (cellulose-containing raw material)

Mixings with the cellulose powder were carried out in the following ratios:

Contrary to the paper sludge the cellulose powder does not contain water, therefore its addition was adapted to the dry matter content of the paper sludge. The compressive strength and the water uptake was measured following a 28 days curing and drying time. The water uptake investigations were supplemented with a floating experiment. Each of the paper concrete cubes floated on the water, but in comparison with a previous experiment they started to sink faster in the course of the water uptake. None of the sunken specimen fell apart, they kept they form, both their volume and shape.

Example C

Plastic reinforced paper strip (cellulose-containing raw material)

Mixings with the plastic reinforced paper strip were carried out in the following ratios:

Experiment number 9. 10. 11. 12.

cement/cellulose/water 1 :1:3 1 :0.5:3 2:0.5:4 3:0.5:4

Compressive strength 1 N/m² 1 N/m² 3 N/m² 4 N/m²

Water uptake 0.3 0.3

0.4 kg/kg 0.6 kg/kg kg/kg kg/kg

Water uptake with 0.2 0.1

0.2 kg/kg 0.4 kg/kg additive kg/kg kg/kg Water uptake of the plastic reinforced paper strips is much lower than that of the previous raw materials, therefore the curing time of the finished concrete becomes shorter. The compression strength and water uptake data are values measured after the 28 days curing and drying time, but since these systems contained much lower amount of water, curing was also faster. The water uptake experiments of the finished concrete prepared with plastic reinforced paper strips were similar to the previous ones, with the difference that the retention was much greater, the time of absorbance of the same amount of water was three times longer than before. Even in this case the sunken specimen fell apart, they kept they form, both their volume and shape.

Example D

Ground aluminium-paper-plastic combination (cellulose-containing raw material)

Mixings with the ground aluminium-paper-plastic combination were carried out in the following ratios:

Experiments performed with the ground aluminium-paper-plastic combination showed a large difference compared to the cellulose powder. Their water intake is significantly lower, therefore in addition to wetting the paper-content, the highest amount of the water was used for wetting the cement and for the participation in cement binding. This was our first experiment, in which we had to pay attention to the fact that the curing finished concrete do not get cracked, and the concrete do not burn out. Both the curing speed and the drying was faster, fluxing agent must have been added, 90-120 g fluxing agent was mixed to the composition specified in the table. According to this even the results of the water uptake investigations were irregular. According to the standard, compression strength and water uptake data were measured after the 28 days curing and drying time, disregarding the speed of curing. The water uptake investigations were supplemented with a floating experiment. Each of the paper concrete cubes floated on the water, but in comparison with the previous experiments they started to sink very slowly in the course of the water uptake, and floated in the water for a very long time. None of the sunken specimen fell apart, they kept they form, both their volume and shape. The value of the compression strength was not influenced by the use of the fluxing agent.

Example E

Agricultural seed-coat grist (cellulose-containing raw material)

Mixings with the agricultural seed-coat grist were carried out in the following ratios:

The experiments performed with the agricultural seed-coat grist resulted in the mixture of the experiments performed with the aluminium-paper-plastic combination and the cellulose powder. The coat grist did not take up as much water as the cellulose powder, but more than the combination. Even in this case the amount of the water could be reduced by the use of a fluxing agent. Its amount even in this case was 100 g for the composition specified in the table. Their water uptake is significantly lower, therefore in addition to wetting the cellulose content the highest amount was used for wetting the cement and for the participation in cement binding. In the course of this experiment we did not have to take care that the curing finished concrete do not get cracked, and the concrete do not burn out, because the soaked seed-coat grist lost sufficient amount of water for the cement binding and for the transfer of the resulting heat. The curing speed and the drying was the same as in the first three experiments. According to the standard, the compression strength and water uptake data were measured after the 28 days curing and drying time, disregarding the speed of curing. The water uptake investigations were supplemented with a floating experiment. Each of the paper concrete cubes floated on the water, but in comparison with a previous experiment they started to sink very slowly in the course of the water uptake, and floated in the water for a very long time. Due to the hydrophobic character of the seed-coats there was no complete sinking. None of the sunken specimen fell apart, they kept they form, both their volume and shape.

Example F

Ground corn cob (cellulose-containing raw material)

Mixings with the ground corn cob were carried out in the following ratios:

The experiments performed both with the agricultural seed-coat grist and the ground corn cob were identical with each other, both from the aspects of homogeneity and the mechanical characteristics. Its mixing was somewhat simpler, reaching the consistency was easier, which could be poured into a mould. Even the ground corn cob did not take up as much water as the cellulose powder, but more than the combination. It was not necessary to reduce the amount of the water uptake with the application of a fluxing agent. According to the standard, the compression strength and water uptake data were measured after the 28 days curing and drying time, disregarding the speed of curing. The water uptake investigations were supplemented with a floating experiment. Each of the paper concrete cubes floated on the water, but similarly to the previous experiment they started to sink only very slowly in the course of the water uptake, and floated in the water for a very long time. Due to the ground corn cob there was no complete sinking even in this case. None of the sunken specimen fell apart, they kept they form, both their volume and shape.

In order to speed up curing and for the rapid exit of the unbound water fluxing agent was also used for the preparation of the finished concrete. This amounts to 120 g/6-9 kg wet finished concrete. Addition of the fluxing agent reduces the amount of the water necessary for mixing and homogenization, this way the drying times have also shortened. In order to reduce the water uptake some of the watertight additives available on the market were also tried. In each case the mixing experiments were initiated with the same composition, but with the addition of 100-150 g /6-9 kg (1-3 wt%) wet finished concrete watertight additive, whereupon water uptake reduced with 40-60 %.

Hereinafter those examples are described, which demonstrate more specifically the solution of the invention, the addition of vegetable oils.

For each raw material our experiments were performed with the material composition reached the highest compression strength.

Example 1

In case of the paper sludge we proceeded as follows:

3 kg cement was added to the 4 kg paper sludge already pulped, and was homogenized with intensive agitation. 150 g watertight additive available on the market as a white suspension was added to the mass already prepared. Following homogenization the mixture was poured into a mould, and the examinations were carried out 28 days later. Water uptake reduced with 40% compared to the sample without the additive. The same experiment was performed with vegetable oils, i.e. sunflower oil, corn oil, rapeseed oil, used cooking oil. The composition of the finished concrete was not changed, in three series of experiments 100-200-300 g vegetable oil was added to the concrete pulp already blended, homogenized, and homogenized with intensive agitation. Following this it was moulded into cast, and the water uptake was measured after 28 days of drying time. Reduction of the water uptake of the sample prepared with 100 g oil was not significant yet, only 300 g water was taken up by 1 kg paper concrete. Both the 200 g and 300 g samples showed 100-100 g water uptake, which is significantly lower than what was obtained by using the products available on the market.

Example 2

In case of cellulose powder we proceeded as follows:

Pulping was performed with 1 kg cellulose powder and with 5 kg water, and 3 kg cement powder was added to this mass. 150 g watertight additive available on the market as a white suspension was added to the mass already prepared. Following homogenization the mixture was poured into a mould, and the examinations were carried out 28 days later. Water uptake reduced with 50%, compared to the sample without the additive. The same experiment was performed with vegetable oils, i.e. sunflower oil, corn oil, rapeseed oil, used cooking oil, in the same series of experiments, which has already been described with the paper sludge. The results were very similar, water uptake was measured after 28 days of drying time. Reduction of the water uptake of the sample prepared with 100 g oil was not significant yet, only 600 g water was taken up by 1 kg paper concrete. Both the 200 g and 300 g samples showed 100-100 g water uptake, which is significantly lower than what can be provided by using the products available on the market.

Example 3

In case of the plastic reinforced paper strips we proceeded as follows:

0.5 kg strips and 4 kg water was used for pulping, and 3 kg cement was added to this slowly. Following this the experiments were performed as described above, with 150 g watertight additive available on the market as a white suspension the water uptake capability reduced from 600 g water / 1 kg paper concrete to 400 g. With the vegetable oils used by us this reduced further, with 100 g oil we could keep the 400 g water uptake per kg, with 200 and 300 g vegetable oil this was further reduced to 100 g water uptake.

Example 4

In case of the aluminium-paper-plastic we proceeded as follows:

The 1 kg paper derivative was pulped with 4 kg water, and 3 kg cement powder was added to this mass, following this it was homogenized with intensive agitation. 150 g watertight additive available on the market as a white suspension was added to the mass already prepared. Following homogenization the mixture was poured into a mould, and the examinations were carried out 28 days later. Compared to the sample without the additive water uptake did not reduce at all. The same experiment was performed with vegetable oils, i.e. sunflower oil, corn oil, rapeseed oil, used cooking oil. The composition of the finished concrete was not changed, in three series of experiments 100-200-300 g vegetable oil was added to the concrete pulp already blended, homogenized, and homogenized with intensive agitation. Following this it was moulded into cast, and the water uptake was measured after 28 days of drying time. Even in this case reduction of the water uptake of the sample prepared with 100 g oil was unsuccessful, and 1 kg paper concrete took up 200 g water. The 200 g and 300 g samples showed 100- 100 g water uptake, which means a 50% improvement compared to the efficiency of the products available on the market.

Example 5

In case of the seed-coat grist we proceeded as follows:

Altogether 1 kg seed-coat grist was wetted with 6 kg water, and 3 kg cement powder was added to the agitable mass. 150 g watertight additive available on the market as a white suspension was added to the mass already prepared. Following homogenization the mixture was poured into a mould, and the examinations were carried out 28 days later. Compared to the sample without the additive water uptake reduced with 50%. The same experiment was performed with vegetable oils, i.e. sunflower oil, corn oil, rapeseed oil, used cooking oil. The composition of the finished concrete was not changed, in three series of experiments 100-200- 300 g vegetable oil was added to the concrete pulp already blended, homogenized, and homogenized with intensive agitation. Following this it was moulded into cast, and the water uptake was measured after 28 days of drying time. Even in this case reduction of the water uptake of the sample prepared with 100 g oil was unsuccessful, because it produced an effect identical with that of the watertight additive available on the market, 1 kg paper concrete took up 300 g water. Both the 200 g and 300 g samples showed 100-100 g water uptake, which is significantly lower than what was obtained by using the products available on the market.

Example 6

In case of the ground corn cob we proceeded as follows:

5 kg water and 3 kg cement was added to corn cob grist, with intensive agitation. 150 g watertight additive available on the market as a white suspension was added to the mass already prepared. Following homogenization the mixture was poured into a mould, and the examinations were carried out 28 days later. Compared to the sample without the additive water uptake reduced with 40%. The same experiment was performed with vegetable oils, i.e. sunflower oil, corn oil, rapeseed oil, used cooking oil. The composition of the finished concrete was not changed, in three series of experiments 100-200-300 g vegetable oil was added to the concrete pulp already blended, homogenized, and homogenized with intensive agitation. Following this it was moulded into cast, and the water uptake was measured after 28 days of drying time. Even in this case reduction of the water uptake of the sample prepared with 100 g oil was unsuccessful, because it produced effect identical with that of the watertight additive available on the market, 1 kg paper concrete took up 300 g water. Both the 200 g and 300 g samples showed 100-100 g water uptake, which is significantly lower than what was obtained by using the products available on the market. The results of the water uptake experiments were evaluated even in tabular form:

According to our investigations the vapour diffusion characteristics of the cellulose- containing products of the invention are similar to that of the products already known.

Therefore the object of the invention, i.e. to reduce the only characteristic disadvantage of the paper concrete having excellent thermal and sound insulation characteristics, the water sensitivity, in such a way, that the vapour diffusion characteristics do not deteriorate, and to keep the compression strength value characteristic for the lightweight concretes, could be realized.

Claims

1. Method for the preparation of cellulose-containing cementitious concrete products with reduced water uptake properties, by using a high cellulose- content component, characterized that the cellulose-containing component, cement, water and optionally a homogenized mixture containing known additives are suspended with 1-20 wt% vegetable oil by weight of the mixture, as a step of manufacturing the concrete product.

2. Method of Claim 1 , characterized that cellulose powder, paper sludge, plastic reinforced paper, aluminium-paper-plastic combinations, vegetable wastes and residues, such as seed-coat and corn cob grist are used as cellulose- containing component.

3. Method according to Claim 1 or Claim 2, characterized that the cellulose based component originates from waste materials.

4. Method of Claim 2, characterized that the grist of high paper-content materials, suitable for storing liquids is used as aluminium-paper-plastic combination.

5. Method of any of Claims 1-4, characterized that sunflower oil, corn oil, rapeseed oil, or used cooking oil is used as vegetable oil.

6. Use of the concrete product prepared with the procedure of any of Claims 1-5, for the preparation of lightweight concrete.

7. Use of the concrete product prepared with the procedure of any of Claims 1-5, for the preparation of masonry blocks, thermal and sound insulating panels and floors.