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Title:
CONCRETE-CONTAINING BUILDING MATERIAL, MANUFACTURING METHOD AND USE
Document Type and Number:
WIPO Patent Application WO/2003/106367
Kind Code:
A1
Abstract:
The invention relates to a concrete-containing building material comprising a first amount of concrete sludge comprising water and dry matter, which dry matter comprises cement, gravel and sand and a second amount of cement. The invention is characterised in that the concrete sludge also comprises oil; and that the building material comprises at least a further, third component, said third component comprising gravel, and that the building material further comprises lime. Hereby hardening of the concrete sludge with components is obtained, which material can be recycled eg for road construction. Also an encapsulation of the environmentally hazardous oil is achieved.

Inventors:
Christensen, John Ravn (Kalundborgvej 14 B, Holbæk, DK-4300, DK)
Application Number:
PCT/DK2003/000291
Publication Date:
December 24, 2003
Filing Date:
May 05, 2003
Export Citation:
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Assignee:
MOGENSTRUP GRUSGRAV & GENBRUGSINDUSTRI (v/John Ravn Christensen, Virkelyst 1, Regstrup, DK-4420, DK)
Christensen, John Ravn (Kalundborgvej 14 B, Holbæk, DK-4300, DK)
International Classes:
C04B18/02; C04B18/16; C04B28/02; E01C7/14; (IPC1-7): C04B18/16; C04B28/00
Foreign References:
DE10021792A12001-11-22
US5575426A1996-11-19
DE19530143A11997-02-20
EP0062339A21982-10-13
DE4206900A11993-09-09
Other References:
PATENT ABSTRACTS OF JAPAN vol. 199, no. 808 30 June 1998 (1998-06-30)
DATABASE WPI Week 200009, Derwent World Patents Index; Class D15, AN 2000-098309, XP002974020
Attorney, Agent or Firm:
Zacco, Denmark A/s (Hans Bekkevolds Allé 7, Hellerup, DK-2900, DK)
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Claims:
C I a i m s
1. A concretecontaining building material comprising a first amount of concrete sludge comprising water and dry matter, said dry matter comprising cement, gravel and sand and a second amount of cement, characterised in that the concrete sludge also comprises oil and that the building material comprises at least a further third component, which third component comprises gravel ; and that the building material further comprises lime.
2. A concretecontaining building material according to claim 1, characterised in that the material further comprises a fourth component comprising puzzolanas.
3. A concretecontaining building material according to any one of the preceding claims, characterised in that the gravel contains lime.
4. A concretecontaining building material according to any one of the preceding claims, characterised in that the gravel contains lime, preferably 210 percent by weight; and that the remainder is constituted of minerals and water.
5. A concrete containing building material according to claims 24, characterised in that the fourth component comprises fly ashes.
6. A concrete containing building material according to any one of the preceding claims, characterised in that the sludge comprises 2040 percent by weight of liquid.
7. A concrete containing building material according to any one of the preceding claims, characterised in that the dry matter of the sludge comprises fly ashes.
8. A concretecontaining building material according to any one of the preceding claims, characterised in that the lime comprises a separately added component.
9. A concretecontaining building material according to any one of the preceding claims, characterised in that the building material is, following hardening, divided into fractions with a maximum diameter of 3.2 cm.
10. A concretecontaining building material according to any one of the preceding claims, characterised in that, prior to. drying and setting, the building material comprises 1718 percent by weight of concrete sludge, 65 66 percent by weight of wet gravel, 1011 percent by weight of cement, 56 percent by weight of fly ashes.
11. A concretecontaining building material according to any one of the preceding claims, characterised in that, following solidification, the building material comprises 1314 percent by weight of dry matter from the concrete sludge, 6768 percent by weight of dry gravel from wet gravel, 1112 percent by weight of cement, 67 percent by weight of fly ashes, and wherein the lime constitutes 610 percent by weight of the material.
12. A method of manufacturing concretecontaining building material from a first amount of concrete sludge comprising water and dry matter, which dry matter comprises cement, gravel and sand and a second amount of cement, characterised in that the concrete sludge also comprises oil ; and that the cement is admixed with a third component comprising gravel in a mixer receptacle ; and that the building material further comprises lime added as a separate component and/or added as constituting a part of the gravel ; and that the concrete sludge is subsequently added.
13. A method according to claim 12, characterised in that the mixer receptacle is fed with a fourth component comprising puzzolanas and admixed with the third component and the cement prior to addition of the concrete sludge.
14. A method according to claim 12 or 13, characterised in that the components are mixed for 610 minutes.
15. A method according to claims 1214, characterised in that the mixture is poured into at least one reservoir for hardening, said hardening process taking place for 24 weeks.
16. A method according to claims 1215, characterised in that the solidified material is subsequently crushed to fractions with a maximum diameter of 3.2 cm.
17. A concretecontaining building material for road surfacing comprising cement, characterised in that the material is composed of a solidified mixture of cement, cement sludge, fly ashes, lime, oil, and gravel, said mixture being divided into fragments with a maximum mean diameter of 3.2 cm before the material is being used for road surfacing.
18. A use of the method according to claims 1216 for the manufacture of the building material according to claims 111.
19. A use of the building material according to claims 112 and the method according to claims 1216 for road surfacing material according to claim 17.
Description:
CONCRETE-CONTAINING BUILDING MATERIAL, MANUFACTURING METHOD AND USE The invention relates to concrete-containing building material comprising a first amount of concrete sludge comprising water and dry matter, said dry matter comprising cement, gravel and sand and a second amount of cement.

The invention also relates to a method of manufacturing concrete-containing building material on the basis of a first amount of concrete sludge comprising water and dry matter, said dry matter comprising cement, gravel and sand and a second amount of cement.

The invention further relates to a concrete-containing building material for road surfacing comprising cement, and finally the invention relates to use of both method and said building materials.

In connection with the manufacture of concrete material in large mixer plants a surface coating is performed within these by use of oil in order to avoid that the concrete hardens on the inside of the machinery. Following mixing, a cleaning takes place by spraying with water. The concrete sludge that thus results comprises on the one hand dry matter admixed with water, but also oil. So far it has not been possible to use this material and make it solidify, and therefore the concrete sludge as such has brought about a comprehensive environmental issue.

JP 10 071 377 teaches a method of admixing concrete sludge with earth, sand and cement, following the substance is reused. The problem with this substance is that it requires much cement to make it solidify, and likewise the additional materials, earth and sand, do not contribute considerably to the strength properties of the final material, nor do they contribute to the hardening process as such. Nor will such mixture be able to perform an incorporation of the oil which is brought about precisely in case of concrete

sludge mixed in said machinery; and therefore the material manufactured in the Japanese application will cause seepage of the oil over time.

DE-100 21 792 A1 teaches a method of recycling concrete sludge, wherein the concrete sludge with cement and optionally gravel is admixed for providing secondary building material. However, the method is unsuitable for encapsulating the oil that exists in concrete sludge polluted with oil.

It is thus the object of the present invention to provide both a construction material and a method that remedy the above-referenced problems and wherein a very strong concrete-containing building material is thus achieved that, following solidification and following fragmentation, lends itself for use ia for road construction. Moreover it is achieved that the oil-polluted concrete sludge that was so far not usable is recycled in a sensible manner, while simultaneously it is ensured that the oil that earlier caused seepage-also from non-hardened concrete sludge-is now encapsulated; and whereby the environmentally hazardous oil seepage is avoided.

This object is achieved with a concrete-containing building material of the kind described above, and wherein the concrete sludge also comprises oil ; and wherein the building material comprises at least a third component, said third component comprising gravel ; and wherein the building material further comprises lime.

The object is further obtained with a method of the kind described above, and wherein it further comprises oil and wherein the cement is admixed with a third component comprising gravel in a mixer receptacle; and wherein the building material further comprises lime added as a separate component and/or added as constituting a part of the gravel ; and wherein the concrete sludge is subsequently added.

The concrete-containing building material is thus provided by gravel, cement and fly ashes being supplied to a mixer receptacle. They are thoroughly mixed, following which the concrete sludge produced by the cleaning of the concrete mixer machinery is supplied to the dry substance, following which mixing takes place for 6-10 minutes. In this context it should be noted that this mixing time is twice that of the normal time.

In the event that the substance is too dry, more water is added. The strength achieved with the finished product is about 12-13 mega-newton. Now the material solidifies in the reservoir and when it has set for a couple of days it will typically rest for post-hardening for a period of 2-4 weeks. Depending on the intended use of the material, a crushing, grinding will take place and wherein the mean diameter will typically be 3,2 cm in those cases where the material is to be used for road construction. In those cases where the material is to be used for some other use of a different nature, the fragment size will be adjusted accordingly.

Lime can be added to the mixture as a separate component and/or constitute a part of the gravel. Lime ensures that the hardening takes place in such a manner that the oil crystallises firmly into the product and that hence it cannot be washed out.

By providing concrete-containing material according to the invention and as further recited in claim 2 it is achieved that the expensive cement goes a longer way and that the material thus added contains the strong silicon that distinguishes itself precisely in that it can be combined with calcium hydroxide. Besides, the puzzolana added is finely ground.

By providing a concrete-containing building material according to the invention as further featured in claims 3 and 4 it is achieved that the hardening process takes place using lime from the gravel, said lime

encapsulating the oil. Said lime interval applies to wet gravel wherein the water content is about 4%.

By providing a concrete-containing building material and as further featured in claim 5 it is accomplished that the cement is caused to go a longer way, while simultaneously the adverse fly ashes are dispensed with. Thus, fly ashes also partake in the hardening process.

By providing a concrete-containing building material according to the invention as further recited in claims 6 and 7, a usable and good composition of the concrete sludge is obtained.

By providing a concrete-containing building material according to the invention as further featured in claim 8 addition of the lime material is further obtained.

By providing a concrete-containing building material according to the invention as further recited in claim 9, a material is accomplished that is suitable for use in road surfacing.

By providing a concrete-containing building material according to claims 10 and 11 a convenient composition of the individual components is obtained, wherein, as will appear from claim 10, it comprises the components containing liquid, and wherein, as recited in claim 11, it comprises the same components, but wherein the liquid has been drawn out.

As mentioned, the invention also relates to a method as featured in claim 12.

The claims according to claims 13-16 relate to convenient steps in the method.

Furthermore, the invention relates to concrete-containing building material as taught above, and wherein the material is composed of a solidified mixture of cement, cement sludge, fly ashes and gravel, which mixture is divided into fragments with a maximum mean diameter of 3.2 cm before the material is used for road surfacing. Thereby a material is achieved that is well-suited for the construction of roads.

Finally the invention relates to use of both the method and the building material as recited in claims 18 and 19; wherein it is to be noted in this context that the method specified is suitable for the manufacture of the concrete-containing building material and also of concrete-containing building material for road surfacing.

The invention will now be explained in further detail.

Following mixing of an amount of concrete in a machine, the machine is to be cleaned. This is typically performed by means of water flushed under high pressure onto the inside of the machinery. It is, as mentioned, coated with the oil to ensure that solidified concrete does to adhere to the surface.

Besides, the concrete sludge that typically contains about 30% of water also contains cement, gravel, fly ashes and sand.

The concrete sludge is supplied to a mixer receptacle wherein cement and gravel was initially admixed and a puzzolana, preferably used fly ashes. The used gravel is so-called wet gravel and contains up to maximally 10% of liquid. Besides, the gravel distinguishes itself in containing lime as well, typically about 2-10 percent by weight, while the remainder is constituted of minerals. In this context it should be mentioned that it is essential that the gravel comprises lime, since it is this component that partakes in the hardening process as such and/or that lime is added separately. The amount of lime added may be up to 20 percent by weight of the mixture.

The cement as such consists of a mixture of lime and clay and, besides, it is in accordance with known principles. The cement constitutes the expensive component, for which it is desired to economize as much as possible. The puzzolanas distinguish themselves in that they consist of silicon that can combine with calcium hydroxide. In this case fly ashes are used that are dummy puzzolana produced as combustion residue for power plants when the boilers are fired with finely-ground carbon. The fly ashes primarily consist of glass in the form of small beady particles. When admixed with concrete, the fly ash entails improved processability. Besides it contributes to the development of the strength of the concrete, in particular after 28 days. The fly ashes also contain a small or large amount of non-combusted carbon that may give rise to colour variations. Besides, it should be noted that the used cement may be eg Basis@, Aalborg Cement@, which is a limestone cement.

A convenient recipe of the ratio of the individual components is 28 kilo of sludge, 107 kilo of wet gravel, 17 kilo of cement and 9 kilo of fly ashes. It is admixed and liquid is added as needed. Such recipe yields a percent by weight corresponding to 17-18 percent by weight of concrete sludge, 65-66 percent by weight of wet gravel, 10-11 percent by weight of cement and 5-6 percent by weight of fly ashes. If these data are purged of the liquid that is typically present, about 30% of liquid in the concrete sludge and up to 10% in the wet gravel, the result will be 13-14% of dry matter from the concrete sludge, 67--68% of dry gravel from the wet gravel, 11-12 percent by weight of cement and 6-7 percent by weight of fly ashes. Then the material is mixed and poured into a mould where it solidifies, and following a couple of days it will be laid out for post-hardening, typically for 2-4 weeks. The material is subsequently subjected to fragmentation, wherein-as mentioned-the crushing will bring about a mean diameter of 3.2 cm, if this concrete- containing material is to be used for road surfaces. Besides it should be noted that the basic size of dry matter in the sludge is typically about 0.5 cm. The gravel used has a grain size of typically 0-8 mm. However it may very well be more coarse-grained; wherein, however, the desired grain size is imparted thereto precisely in the grinding that subsequently takes place.