ES2392069A1 - SELF-LEVELING COMPOSITION. - Google Patents

Abstract

Self-leveling composition # The present invention relates to a new self-leveling composition comprising cement, limestone sand, limestone filler, additives and thermally activated paper sludge. Furthermore, the present invention relates to the use of said compositions as self-leveling mortars.

Description

SELF-LEVELING COMPOSITION

The present invention relates to a new self-leveling composition comprising cement, limestone sand, limestone filler, additives and thermally activated paper sludge. Furthermore, the present invention relates to the use of such compositions as self-leveling mortars.

STATE OF THE PREVIOUS TECHNIQUE

Calcium carbonate-based fines (called limestone fillers) are widely used and essential for the manufacture of self-leveling mortars (MAN) and self-compacting concrete (HAC). Therefore, the products used are mainly natural materials such as limestone and dolomite. According to the European HAC Directive these materials are classified as Inert or semi-inert Type 1 Additions. In the bibliography (Domone PL and Soutsos Mn, Magazine Concrete Research, 49 (180) (1997) 263-264 and Gomes PCC, Gettu R, Agulló L and Bernard C, Cemento y Hormigón, (832) (2002) 30-42 ) The incorporation of other additions such as pozzolans (silica fume, fly ash and blast furnace slag) is also included with the sole objective of acting as correctors in the content of fines (Type 2 according to The European Guidelines for Self Compacting Concrete, 2005 ).

These self-leveling mortars and concretes are characterized by their high content in fines whose main function is to give cohesion and avoid the segregation of the mixture. Calcium carbonate-based fines (limestone fillers) are widely used and can give excellent rheological properties and a good finish on their own. In general, fines percentages above 70% are desirable, with sizes below 63 microns. Obtaining limestone filler inevitably goes through the extraction, transport and crushing of limestone material, which entails negative environmental effects and acoustic problems for the human population.

For this reason, the search for alternative materials from industrial waste is a priority line of Environmental Policies worldwide (Single European Act, Maastrich Treaty), since they argue the environmental advantages in the protection of natural spaces and prioritize the recycling of industrial waste as alternative raw materials. Recently, Directive 2008/98 / EC establishes measures aimed at protecting the environment and human health by preventing or reducing the adverse impacts of waste generation and management, reducing the global impacts of the use of resources. and improving the effectiveness of such use.

Therefore, and as previously stated, it is necessary to develop new production alternatives for self-leveling and self-compacting mortars that do not negatively influence the environment and that report a substantial benefit in terms of industrial waste disposal.

DESCRIPTION OF THE INVENTION

The present invention refers to a new composition that solves all the aforementioned problems, since it comprises, in addition to the usual components, an activated product from the controlled calcination of the paper sludge residue, which has a mostly limestone nature, and to a lesser extent, by metakaolin.

This mixed nature provides certain advantages over the same natural limestone materials normally used in self-leveling mortars (MAN) and self-compacting concrete (HAC):

1) The majority presence of limestone gives it the same properties as limestone filler as the natural ones normally used in the manufacture of these matrices, except for the environmental component that involves taking advantage of industrial waste.

2) The presence of metakaolin gives this product an added value to the limestone component, as is its pozzolanic nature, well known in the cement sector for the improved performance of the cements made with them.

On the other hand, the technical advantages offered by this new and surprising composition are:

•

Easy to get since it is a commercial product. According to the data available in Spain, the production of specific waste from paper processes (LER 0303) in 2006 amounted to a total of

1,400,000 tons. From said residue, it is possible to obtain

350,000 tons of calcined product with a high content of calcium carbonate, and therefore with high potential to be used as a limestone filler in the manufacture of MAN and HAC. In Spain, around 2,340,000 tons of self-leveling mortars and concretes are consumed, which could absorb up to 2,340 tons of the calcined product from the thermal activation of paper sludge.

•

Avoid dust and acoustic contamination associated with the extraction, transport and crushing of natural fillers.

•

Easy handling and dosing in the plant.

•

It does not need special facilities for its storage.

•

Improves flexural and compression resistance compared to the standard mortar.

•

The resistance to adhesion increases 30% more than in the standard.

•

Denser and more compact self-leveling mortars with reductions of the average pore size up to 50% after 28 days of curing.

Due to the chemical and physical characteristics of the commercial product and its limestone nature, it can be used as a partial replacement for the natural limestone filler for the manufacture of MAN and HAC matrices, with the consequent technical, economic and environmental benefit.

The object of this invention is related to a new use for a commercial industrial product, paper sludge residue from the paper industry once thermally activated, as a substitute material for the natural limestone filler commonly used in the manufacture of self-leveling mortars and concretes.

Finally, with the present invention it is possible to have a new range of limestone filler recycled to the already existing natural ones on the market; with the objective of:

1) Provide a new use for this product to the existing one (pozzolanic material for cements).

2) Reduce the environmental problem that involves the extraction, transport and crushing of natural limestone.

3) Improve some of the properties of current commercial self-leveling mortars.

4) Reduce the negative social impact on the dumping of industrial waste in landfill.

5) Contribute to sustainable development in the construction sector.

Therefore, a first aspect of the present invention refers to a new composition comprising:

to.

thermally activated sludge;

b.

limestone sand;

c.

limestone filler;

d.

cement;

and.

water and

F.

additives.

According to a preferred embodiment, the thermally activated sludge is in a proportion by weight to the composition of 3 to 6%, preferably 4 to 6% and more preferably 4.5%.

According to another preferred embodiment, the limestone filler is in a proportion by weight with respect to the composition of 4 to 7%, preferably 4 to 6% and more preferably 4.5%

According to another preferred embodiment, the limestone sand is in a proportion of 67%.

According to another preferred embodiment the cement is in a proportion of 1 0.9%.

According to another preferred embodiment, the additives are in a proportion of 0.44%.

According to another preferred embodiment, the water is in a proportion of 12.7%.

According to a preferred embodiment, the thermally activated sludges come from the paper industry having a limestone nature, with lower metakaolin contents.

According to another preferred embodiment, the thermally activated paper muds comprise a limestone part and the metakaolin in a ratio of 2.5-3 / 1 respectively.

According to another preferred embodiment, the thermally activated sludge has a grain size of less than 0.090 mm, preferably below 0.045 mm.

On the other hand and according to another preferred embodiment, the limestone sand has a grain size of less than 8 mm, preferably less than 2 mm.

According to another preferred embodiment, the limestone filler has a grain size of less than 0.125 mm, preferably below 0.063 mm.

According to another preferred embodiment, the cement is of the CEM 1 52.5 N type.

Furthermore and according to another preferred embodiment, the additives are selected from the group consisting of naphtha and cellulose-based plasticizers / fluidizers

According to another preferred embodiment, the weight ratio of thermally activated paper sludge / limestone filler in the modified MAN is 1: 1.

Another aspect of the present invention relates to the use of said composition previously described as self-leveling mortar or as self-compacting concrete.

Another aspect of the present invention refers to the procedure for obtaining the previously described composition, which comprises the following steps, used in the manufacture of mortars and concretes:

to.

carry out a granulometry of the solid components that make up the self-leveling mortar, this being less than 8 mm for limestone, less than O, 125 mm for limestone filler, and less than 0.090 mm for thermally activated sludge.

b.

dry premix all components of the self-leveling mortar.

c.

Knead the resulting dry mixture with the water in a mixer-kneader until you get a homogeneous, fluid and lump-free consistency dough.

According to a preferred embodiment, the solid components of the mortar

Self-leveling have the following granulometry:

-

less than 2 mm for limestone sand;

-

less than 0.045 mm for the limestone filler; and

-

less than 0.063mm for thermally activated sludge.

According to another preferred embodiment, the process described above is carried out at temperatures equal to or lower than OOOºC to avoid the presence of free expansive lime.

Another aspect of the present invention relates to a self-leveling mortar, which comprises the previously defined composition.

Finally, another aspect of the present invention refers to the use of self-leveling mortar for the execution of screeds of floors and continuous screeds.

Throughout the description and claims, the word "comprises" and its variants are not intended to exclude other technical characteristics, additives, components or steps. For those skilled in the art, other objects, advantages, and features of the invention will emerge in part from the description and in part from the practice of the invention. The following examples are provided by way of illustration, and are not intended to be limiting of the present invention.

EXAMPLES

The invention will now be illustrated by tests carried out by the inventors, which shows the effectiveness of the composition object of the present invention.

This exemplary embodiment refers to the analytical results carried out in the laboratory, which were based on evaluating the technical performance of modified self-leveling mortars with different percentages of substitutions of this product of invention and comparing it with the same MAN standard, showing that minimal substitutions are sufficient to substantially improve some of the properties of commercial MANs taken as a reference.

The following describes the preparation of a modified self-leveling mortar with activated paper mud:

The dosage design is articulated around achieving a consistency that is fluid enough to guarantee self-leveling of the mortar. The percentage of substitution of natural limestone filler for activated sludge filler is 50%. The sand used mainly as raw material in the self-leveling mortar is fine limestone sand AF-T-0/2-C, according to UNE 14611 O for aggregates for mortars.

Table 1 shows the composition of the modified mortar compared to the reference mortar. The study of the properties of the self-leveling mortar in the fresh state was carried out according to the specifications defined in the EN 13454-2 standard; while for the properties in the hardened state according to the UNE-EN 13892-2 standard.

The results obtained for the consistency, workability time, mechanical resistance and adherence tests are shown in Table 2.

Claims (20)

1. Composition comprising:

to.

thermally activated paper sludge;

b.

limestone sand;

c.

limestone filler

d.

cement;

and.

Water; and

F.

additives.

2.

Composition according to claim 1, where the thermally activated sludge comes from the paper industry.

3.

Composition according to any of claims 1 or 2, where the following components are in the following proportions:

to.

3 to 6% thermally activated paper sludge; and

b.

limestone filler from 4 to 7%.

Four.

Composition according to claim 3, where the components are in the following proportions:

to.

thermally activated paper sludge from 4 to 6%; and

b.

limestone filler from 4 to 6%.

5.

Composition according to claim 4, where the components are in the following proportions:

to.

4.5% thermally activated paper sludge; and

b.

limestone filler of 4.5%;

6.

Composition according to any of claims 1 to 5, where the calcined sludges comprise limestone and metakaolin.

7.

Composition according to claim 6, where the limestone and metakaolin part of the calcined sludge is in a ratio of 2.5-3 / 1 respectively.

8.

Composition according to any of claims 1 to 7, where the thermally activated sludge has a grain size of less than 0.090 mm.

9.

Composition according to claim 8, where the thermally activated sludge has a grain size of less than 0.045 mm.

1O. Composition according to any of claims 1 to 9, where the limestone sand has a grain size of between 0.1 to 8 mm.

eleven.

Composition according to claim 1O, where the limestone sand has a grain size of less than 2 mm.

12.

Composition according to any of claims 1 to 11, wherein the limestone filler has a grain size of less than 0.125 mm.

13.

Composition according to claim 12, where the limestone filler preferably has a grain size of less than 0.063 mm.

14.

Composition according to any of claims 1 to 13, where the cement is of the CEM 1 52.5 N type.

fifteen.

Composition according to any of claims 1 to 14, where the additives are selected from the group consisting of plasticizers / fluidizers based on naphtha and cellulose.

16.

Use of the composition of claims 1 to 15, as a self-leveling mortar.

17.

Procedure for obtaining the composition of the Claims 1 to 15, comprising the following steps:

to.

carry out a granulometry of the solid components that make up the composition, this being between 0, 1 and 8 mm for the sand limestone, less than 0, 125 mm for the limestone filler and below 0.090 mm, for thermally activated sludge;

b.

dry premix all components of the composition; and

c.

knead the resulting dry mixture with the water in a mixer kneader until a homogeneous, fluid consistency dough is obtained and free of lumps.

18.

The method according to claim 17, wherein the components Self-leveling mortar solids have the following granulometry: -lower than 2 mm for limestone sand; -lower than 0.045 mm for the limestone filler; and -lower than 0.063mm for thermally activated sludge.

19.

The method according to any of claims 17 or 18, where it is carried out at temperatures equal to or below 700ºC.

twenty.

Self-leveling mortar comprising the composition according to claims 1 to 15.

twenty-one.

Use of the self-leveling mortar according to claim 20, for the execution of screeds of floors and continuous screeds.