Binder composition for improved mortars and coatings

Abstract

A binder composition for enhanced mortars and coatings, comprising a first conventional mineral component and a second component based on powdery slaked lime, wherein said second component based on powdery slaked lime has a specific surface area calculated according to the BET method of less than 12 m.sup.2/g, advantageously less than 11 m.sup.2/g, in particular less than 10 m.sup.2/g, preferably less than 9 m.sup.2/g and its uses as well as the enhanced coating or mortar systems comprising an aggregate of the mineral type and the aforesaid composition.

Claims

1. A binder composition for mortars and coatings, comprising a first conventional mineral component and a second component based on powdery slaked lime, wherein said second component based on powdery slaked lime has a specific surface area calculated according to the BET method of less than 12 m.sup.2/g and wherein said second component is present in an amount equal to or greater than 12% and equal to or less than 80% by weight, based on the total weight of the binder composition.

2. The binder composition according to claim 1 wherein said second component has a specific surface area calculated according to the BET method of less than 8.5 m.sup.2/g.

3. The binder composition according to claim 1, wherein said first conventional mineral component is selected from the group consisting of cements, standard slaked or air lime, natural or artificial hydraulic lime, masonry binders, pozzolanic and hydraulic binders, gypsum and mixtures thereof.

4. The binder composition according to claim 3, wherein said cement is selected from the group consisting of common cements, refractory cements, molten aluminous cements, prompt cements, Portland cements, slags from blast furnaces, fly ash and mixtures thereof.

5. The binder composition according to claim 1, wherein said second component has particles having a d3 greater than 0.1 m and a d98 of less than or equal to 250 m.

6. The binder composition according to claim 1, wherein said second component has particles having a d93 of less than or equal to 90 m.

7. The binder composition according to claim 1, wherein said second component based on powdery slaked lime has a total pore volume calculated according to the BJH method of nitrogen desorption greater than or equal to 0.02 cm.sup.3/g.

8. The binder composition according to claim 1, wherein said second component based on powdery slaked lime has a total pore volume calculated according to the BJH method of nitrogen desorption of less than or equal to 0.07 cm.sup.3/g.

9. The binder composition according to claim 1, further comprising an air entrainer comprising a surfactant or tenside.

10. The binder composition according to claim 1, further comprising a water retaining agent, the water retaining agent being selected from the group consisting of cellulose ethers, guar gums, derivatives thereof and mixtures thereof.

11. The binder composition according to claim 1, further comprising a rheology modifier comprising a hydrocolloid.

12. The bind composition according to claim 1, further comprising a hydrophobicizing agent selected from the group consisting of salts of fatty acids including stearates and oleates, vegetable and mineral oils, silanes, siloxanes and mixtures thereof.

13. The binder composition according to claim 1, further comprising a third component which is organic and which comprises an industrial lattice selected from the group consisting of copolymers based on polyvinyl acetate/ethylene, polyvinyl acetate/versatate, and styrene/butadiene.

14. The binder composition according to claim 1, wherein said second component based on slaked lime has a bulk density measured according to the EN 459 2 standard of more than 350 kg/m.sup.3.

15. A system of coatings or mortars comprising an aggregate of the mineral type and a binder composition, the binder composition comprising: a first conventional mineral component and a second component based on powdery slaked lime, wherein said second component based on powdery slaked lime has a specific surface area calculated according to the BET method of less than 12 m.sup.2/g wherein said second component is present in an amount equal to or greater than 12% and equal to or less than 80% by weight, based on the total weight of the binder composition.

16. The system according to claim 15, in a dry form, ready to be mixed with water.

17. The system according to claim 15, further comprising water.

18. The system according to claim 15, further comprising an air entrainer comprising a surfactant or tenside.

19. The system according to claim 15, further comprising a water retaining agent, the water retaining agent being selected from the consisting of cellulose ethers, guar gums, derivatives thereof and mixtures thereof.

20. The system according to claim 15, further comprising a rheology modifier which comprises a hydrocolloid.

21. The system according to claim 15, further comprising a hydrophobicizing agent which comprises the salt of a fatty acid, the hydrophobicizing agent being selected from the group consisting of stearates and oleates, vegetable and mineral oils, silanes, siloxanes and mixtures thereof.

22. The system according to claim 15, further comprising a third component which is organic and which comprises an industrial lattice the industrial lattice being selected from the group consisting of lattices based on polyvinyl/ethylene, polyvinyl acetate/versatate, styrene/butadiene copolymers.

23. The binder composition according to claim 1, further comprising an air entrainer, the air entrainer being selected from the group consisting of alkyl sulfates, alkyl sulfonates, ethoxylated fatty alcohols, block copolymers and mixtures thereof.

24. The binder composition according to claim 1, further comprising a rheology modifier, the rheology modifier being selected from the group consisting of polysaccharides, starch derivatives, alginates, guar gums and derivatives thereof, xanthan gums and derivatives thereof, carrageenan gums and derivatives thereof, succinoglycans, superplasticizers selected from the group consisting of polycarboxylates and melamine formaldehydes, and mineral colloids selected from the group consisting of silica and clays, and mixtures thereof.

25. The system according to claim 15, further comprising an air entrainer, the air entrainer being selected from the group consisting of alkyl sulfates and alkyl sulfonates, ethoxylated fatty alcohols, block copolymers and mixtures thereof.

26. The system according to claim 15, further comprising a rheology modifier, the rheology modifier being selected from the group consisting of polysaccharides, starch derivatives, alginates, guar gums and derivatives thereof xanthan gums and derivatives thereof, carrageenan gums and derivatives thereof, succinoglycans, superplasticizers selected from the group consisting of polycarboxylates and melamine formaldehydes, and mineral colloids selected from the group consisting of silica and clays, and mixtures thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) In a particular embodiment, said first conventional mineral component is selected from the group consisting of cements, standard slaked or hydrated lime, air lime, natural or artificial hydraulic lime, binders for masonry, pozzolanic and hydraulic binders, gypsum and mixtures thereof.

(2) In a particular embodiment, said cements are selected from the group of common cements (gray or white), refractory cements, molten aluminous, prompt cements, Portland cements, slags from blast furnaces, fly ash and mixtures thereof.

(3) Preferably, said second component is present in an amount equal to or greater than 12% by weight, preferably equal to or greater than 15% by weight, particularly equal to or greater than 20% by weight, in particular equal to or greater than 30% by weight, advantageously equal to or greater than 40% by weight and equal to or smaller than 80% by weight, in particular equal to or smaller than 70% by weight, advantageously equal to or smaller than 60% by weight, based on the total weight of said binder composition.

(4) Lower contents of said second component in said binder composition would not give the possibility of either benefiting from the advantages of slaked lime as mentioned above or of demonstrating the drawbacks related to the use of the latter and which the present invention precisely seeks to solve.

(5) In a more particular way, said second component has particles having a d.sub.3 greater than 0.1 m, in particular greater than 0.5 m and a d.sub.98 of less than or equal to 250 m, preferably less than or equal to 200 m.

(6) The notation d.sub.x represents a diameter, expressed in m, relatively to which X % of the measured particles or grains are smaller.

(7) In a particularly advantageous embodiment according to the present invention, said second component has particles having a d.sub.93 of less than or equal to 90 m.

(8) In a preferential embodiment according to the present invention, said second component based on powdery slaked lime has a total pore volume calculated according to the nitrogen desorption BJH method of more than or equal to 0.02 cm.sup.3/g, preferably more than or equal to 0.025 cm.sup.3/g.

(9) Advantageously, said second component based on powdery slaked lime has a total pore volume calculated according to the nitrogen desorption BJH method of less than or equal to 0.07 cm.sup.3/g, preferably less than or equal to 0.06 cm.sup.3/g.

(10) By <<total pore volume>> in the sense of the present invention is meant the total volume of the pores for which the size is comprised between 17 and 1,000 (1.7 and 100 nm), measured by nitrogen adsorption manometry and calculated according to the BJH method, after degassing in vacuo at 190 C. for at least 2 hours.

(11) Advantageously, said second component based on slaked lime has a bulk density as measured according to the EN 459-2 standard of more than 350 kg/m.sup.3, preferably more than 400 kg/m.sup.3 and less than 600 kg/m.sup.3, in particular less than 550 kg/m.sup.3.

(12) Preferentially, the composition according to the present invention further comprises an air entrainer such as a surfactant or tenside, in particular selected from the group of alkyl sulfates or sulfonates, ethoxylated fatty alcohols, block copolymers and mixtures thereof.

(13) In an alternative according to the invention, the binder composition may further comprise one or several water retaining agents, for example cellulose ethers or guar gums, derivatives thereof and mixtures thereof.

(14) In further another alternative according to the present invention, the binder composition further comprises a rheology modifier, in particular selected from the group of hydrocolloids, more particularly form the group of polysaccharides, starch derivatives, alginates, guar gums and derivatives thereof, xanthan gums and derivatives thereof, carrageenan gums and derivatives thereof, succinoglycans, superplasticizers like polycarboxylates or melamine-formaldehydes, mineral colloids, in particular silica and clays, and mixtures thereof.

(15) Advantageously, the composition according to the invention further also comprises a hydrophobicizing agent selected from the group of fatty acid salts such as stearates and oleates, vegetable and mineral oils, silanes, siloxanes and mixtures thereof.

(16) Particularly advantageously, the composition according to the present invention further comprises a third organic component selected from the group of industrial lattices such as for example polyvinyl acetate/ethylene copolymers, polyvinyl acetate/versatate copolymers, styrene/butadiene copolymers and the like.

(17) Other embodiments of the binder composition for enhanced coatings and mortars according to the invention are indicated in the appended claims.

(18) The object of the invention is also a system of enhanced coatings or mortars comprising an aggregate of the mineral type and the composition according to the present invention, as mentioned above.

(19) The binder composition for mortars and coatings comprises a first conventional mineral component and a second component based on powdery slaked lime. Said second component based on powdery slaked lime has a specific surface area calculated according to the BET method, of less than 12 m.sup.2/g, in particular less than 11 m.sup.2/g, advantageously less than 10 m.sup.2/g, preferably less than 9 m.sup.2/g.

(20) Advantageously, said second component has a specific surface area calculated according to the BET method of less than 8.5 m.sup.2/g, preferably less than 8 m.sup.2/g, preferentially less than 7.5 m.sup.2/g and in particular less than 7 m.sup.2/g.

(21) In a particular embodiment, said first conventional mineral component is selected from the group consisting of cements, of standard slaked or hydrated lime or air lime, natural or artificial hydraulic lime, binders for masonry, pozzolanic and hydraulic binders, gypsum and mixtures thereof.

(22) Advantageously, the cements are selected from the group of common cements (gray or white), refractory cements, molten aluminous cements, prompt cements, Portland cements, slags from blast furnaces, fly ash and mixtures thereof.

(23) Preferably, said second component is present in an amount equal to or greater than 12% by weight, preferably equal to or greater than 15% by weight, particularly equal to or greater than 20% by weight, in particular equal to or greater than 30% by weight, advantageously equal to or greater than 40% by weight and equal to or less than 80% by weight, in particular equal to or less than 70%, in particular equal to or less than 60% by weight, based on the total weight of said binder composition.

(24) More particularly, said second component has particles having a d.sub.3 greater than 0.1 m, in particular greater than 0.5 m and a d.sub.98 of less than or equal to 250 m, preferably less than or equal to 200 m.

(25) In a particularly advantageous embodiment according to the present invention, said second component has particles having a d.sub.93 of less than or equal to 90 m.

(26) In a preferential embodiment according to the present invention, said second component based on powdery slaked lime has a total pore volume calculated according to the nitrogen desorption BJH method greater than or equal to 0.02 cm.sup.3/g, preferably greater than or equal to 0.025 cm.sup.3/g.

(27) Preferably, said second component based on powdery slaked lime has a total pore volume calculated according to the nitrogen desorption BJH method of less than or equal to 0.07 cm.sup.3/g, preferably less than or equal to 0.06 cm.sup.3/g.

(28) In a preferential embodiment according to the present invention, the system as mentioned above is in a dry form, ready to mix with water.

(29) In an alternative according to the present invention, the system further comprises water and is thus in a ready-to-use form.

(30) Advantageously, said system according to the invention further comprises an air entrainer such as a surfactant or tenside, in particular selected from the group of alkyl sulfates or sulfonates, ethoxylated fatty alcohols, block copolymers and mixtures thereof, which may be added to the aggregate, to the binder composition or to the system after or during the mixing of said binder composition and of the aggregates.

(31) In a particular embodiment of the present invention, the system further comprises one or several water retaining agents, for example cellulose ethers or guar gums, derivatives thereof and mixtures thereof, which may be added to the aggregate, to the binder composition or to the system after or during the mixing of said binder composition and of the aggregates.

(32) In another preferred embodiment of the invention, the system further comprises a rheology modifier, in particular selected from the group of hydrocolloids, more particularly from the group of polysaccharides, starch derivatives, alginates, guar gums and derivatives thereof, xanthan gums and derivatives thereof, carrageenan gums and derivatives thereof, succinoglycans, superplasticizers like polycarboxylates or melamine formaldehydes, mineral colloids, in particular silica and clays, and mixtures thereof, which may be added to the aggregate, to the binder composition or to the system after or during the mixing of said binder composition and of the aggregates.

(33) In further another preferred embodiment of the invention, the system further comprises a hydrophobicizing agent selected from the group of fatty acid salts like stearates and oleates, vegetable and mineral oils, silanes, siloxanes and mixtures thereof, which may be added to the aggregate, to the binder composition or to the system after or during mixing of said binder composition and of the aggregates.

(34) In a preferential embodiment of the invention, the system further comprises a third organic binder selected from the group of industrial lattices based on polyvinyl/ethylene, polyvinyl acetate/versatate, styrene/butadiene copolymers and the like, which may be added to the aggregate, to the binder composition or to the system after or during the mixing of said binding composition and of the aggregates.

(35) Other embodiments of the system of enhanced coatings or mortars comprising an aggregate of the mineral type according to the invention are indicated in the appended claims.

(36) The invention also relates to a use of a binder composition according to the present invention in an enhanced coating.

(37) The invention also relates to a use of a binder composition according to the present invention, in an enhanced mortar.

(38) Advantageously, said use resorts to aggregates which have a particle size such that d.sub.5 is greater than or equal to 63 m and d.sub.98 is less than or equal to 4 mm.

(39) Other embodiments of use of the composition are mentioned in the appended claims.

(40) Other features, details and advantages of the invention will become apparent from the description given hereafter, as non-limiting and with reference to the examples.

EXAMPLES

Example 1.: Impact of Hydrated Lime with a Low Specific Surface Area in a Coating

(41) The binder composition for a coating with high added value mentioned in table 1 was prepared with the following components and in the indicated proportions:

(42) TABLE-US-00001 TABLE 1 Proportion Products (% by weight) Cement CEM I 42.5 R 51% Hydrated lime 47% Redispersible latex powder (Vinnapas 0.4% 8031 H) Water retainer (Tylose MH 15000 YP4) 0.5% Air entrainer (Hostapur OSB) 0.1% Hydrophobicizer (Zinkum 5) 1%

(43) In this formulation, a lime with a high specific surface area (HS) is compared with two limes of low specific surface area (BS), and a standard lime (STD) of a standard specific surface area, according to table 2.

(44) By the expression of specific surface area used in the present invention, is meant the specific surface area measured by nitrogen adsorption manometry and calculated according to the Brunauer, Emmett and Teller model (BET method), after degassing in vacuo at 190 C. for at least 2 hours.

(45) TABLE-US-00002 TABLE 2 Product BET surface area (m.sup.2/g) BJH pore volume (cm.sup.3/g) Lime HS 45.1 0.24 Lime STD-1 15.9 0.08 Lime BS1 8.4 0.04 Lime BS2 7.2 0.04

(46) A coating is prepared starting from the aforementioned binder by adding siliceous sand, so as to obtain the bulk composition mentioned in table 3.

(47) TABLE-US-00003 TABLE 3 Proportion (% by Products weight) Cement CEM I 42.5 R 13% Hydrated lime 12% Reidispersable latex powder (Vinnapas 0.1% 8031 H) Water retainer (Tylose MH 15000 YP4) 0.12% Air entrainer (Hostapur OSB) 0.02% Hydrophobicizer (Zinkum 5) 0.3% Siliceous sand (0.1-0.6 mm) 74.5%

(48) The mixing rate of the fresh coating (water/Solid, W/S) according to table 3 is adjusted in order to obtain a consistency (slump) of the slurry of 1755 mm according to the EN1015-3 standard. The characteristics of the coatings are mentioned in table 4. The density of the fresh coating and the entrained air are evaluated according to the EN1015-6 and EN1015-7 standards. Water retention is evaluated with a device according to the ASTM C91 standard with a negative pressure of 7,000 Pa for 15 min, with the same consistency of the slurry (slump of 1755 mm). Only the water retention value after 15 min is shown.

(49) TABLE-US-00004 TABLE 4 A coating Slump Air Water retention based on W/S[%] [mm] Density [%] 15 min [%] Lime HS 28.4 178 1.7 14 92 Lime STD- 21.5 177 1.6 18 94 1 Lime BS1 21.3 170 1.5 22 95 Lime BS2 20.4 175 1.5 24 96

(50) As this may be seen, coatings based on lime with a low specific surface area (BS) have a lower water demand (W/S). It is well known that a low water demand lowers the risk of shrinkage and cracks in the coating, and increases the mechanical strength of a formulation including a hydraulic binder.

(51) It is also observed that lime with a low specific surface area give the possibility to the organic additives of better fulfilling their role of an air entrainer or water retainer. A higher air level gives the fresh coating better plasticity/handling capability, increases its yield, as well as the isolating power and the resistance to freezing/thawing cycles of the hardened coating. Better retention of water of the fresh coating increases its tolerance towards variable supports, and of high porosity.

(52) Let us note that an increase in the water retention beyond 92% is typically very delicate to obtain while maintaining good handling capability. This strong water retention is further highly sought by one skilled in the art.

Example 2.: Impact of Hydrated Lime with Low Specific Surface Area in an Enhanced Masonry Mortar (II)

(53) The binder composition for a masonry mortar mentioned in table 5 was prepared with the following components and in the indicated proportions:

(54) TABLE-US-00005 TABLE 5 Products Proportion (% by weight) Cement CEM I 42.5 N 84.4% Slaked lime 15.4% Air entrainer (Hostapur OSB) 0.1% Water retainer (Tylose MH 15003 P6) 0.1%

(55) In this formulation, a lime with low specific surface area (BS) is compared with a standard lime (STD) with standard specific surface area according to table 6:

(56) TABLE-US-00006 TABLE 6 Product BET Surface (m.sup.2/g) BJH pore volume (cm.sup.3/g) Lime STD-3 15.2 0.08 Lime BS2 7.2 0.04

(57) An enhanced masonry mortar is prepared starting with the aforementioned binder by adding siliceous sand, so as to obtain the bulk composition mentioned in table 7:

(58) TABLE-US-00007 TABLE 7 Proportion (% by Products weight) Cement CEM I 42.5 N 11% Slaked lime 2% Limestone filler 11% Air entrainer (Hostapur OSB) 0.01% Water retainer (Tylose MH 15003 P6) 0.01% Siliceous sand (0.1-1.2 mm) 76%

(59) The mixing level of the fresh mortar (Water/Solid, W/S) according to table 5 is adjusted in order to obtain a consistency (slump) of the slurry of 1755 mm according to the EN1015-3 standard. The characteristics of the mortars are mentioned in table 8.

(60) The density of the fresh mortar and the entrained air are evaluated according to the EN1015-6 and EN1015-7 standards.

(61) Water retention is evaluated with a device according to the ASTM C91 standard with a negative pressure of 7,000 Pa for 15 min, with the same consistency of the slurry. Only the water retention value after 15 min is shown.

(62) TABLE-US-00008 TABLE 8 Retention of Mortar based W/S Slump Air water 15 min on [%] [mm] Density [%] [%] Lime STD- 14.1 173 1.8 18.0 72 3 Lime BS2 13.7 176 1.6 25.0 75

(63) Again, the lime with low specific surface area (BS) allows the air entrainer and the water retention additive to better fulfill their role with the possibility of optionally reducing their level in the composition or increasing water retention for an equal amount of additives. According to this example, the impact on the air entraining is particularly pronounced and interesting, the impact on the water retention finally being limited because of the low content of water retention additive.

(64) Of course the present invention is by no means limited to the embodiments described above and that many modifications may be provided thereto without departing from the scope of the appended claims.