Castable material based on cementitious binder with shrinkage resistance

Abstract

Some embodiments are directed to a new castable cement based material containing a special admixture based internal curing system to reduce the shrinkage and avoid the formation of cracks, and method of producing the same.

Claims

1. A castable cement based material with enhanced shrinkage resistance, comprising: a Portland cement based binder in an amount of at east 290 kg per cubic meters of fresh castable cement based material; sand having a particle size less than 3 mm in diameter in an amount of between 500 Kg and 1600 Kg per cubic meters of fresh castable cement based material; water; a water/total binder ratio in weight located between 0.25 and 0.7; an internal curing system; a volume of paste in an amount of at east 300 l per cubic meters of fresh castable cement based material; and fine aggregates having a particle size greater than 3 mm and less than 10 mm in diameter or/and coarse aggregates; wherein: the internal curing system is in an amount of between 2 g to 30 g (dry solid content)/liter with respect to the total volume of paste; the internal curing system contains at least a wax emulsion (A) in an amount in dry solid content with respect to the total binder content between 0.04 weight % to 1.35 weight %, and hexylene glycol (B) in an amount in dry solid content with respect to the total binder content is between 0.1 weight % to 3 weight %; and the dry solid content ratio between the wax emulsion (A) and the hexylene glycol (B) in weight is between 0.2 and 1.0.

2. The castable cement based material according to claim 1, wherein the internal curing system further contains a water retention agent (C) and/or a rheology modifier (D).

3. The castable cement based material according to claim 2, wherein the water retention agent and/or rheology modifier is chosen from polysaccharides or polymers of acrylic acid.

4. The castable cement based material according to claim 2, wherein the water retention agent (C) is a polysaccharide.

5. The castable cement based material according to claim 2, wherein the rheology modifier (D) is chosen from at least one of acrylic acid, polyethylene, alkylene oxide polymers and its esters.

6. The castable cement based material according to claim 2, wherein the amount of the water retention agent (C) in dry solid content with respect to the total binder content is located between 0.0025 weight % to 0.20 weight %.

7. The castable cement based material according to claim 2, wherein the amount of the rheology modifier (D) in dry solid content with respect to the total binder content is located between 0.000075 weight % to 0.01 weight % (for rheology modifier being an acrylic acid) or 0.0005 weight % to 0.02 weight % (for rheology modifier being a polysaccharide).

8. The castable cement based material according to claim 3, wherein the water retention agent (C) is a polysaccharide.

9. The castable cement based material according to claim 3, wherein the amount of the water retention agent (C) in dry solid content with respect to the total binder content is located between 0.0025 weight % to 0.20 weight %.

10. The castable cement based material according to claim 4, wherein the amount of the water retention agent (C) in dry solid content with respect to the total binder content is located between 0.0025 weight % to 0.20 weight %.

11. The castable cement based material according to claim 5, wherein the amount of the water retention agent (C) in dry solid content with respect to the total binder content is located between 0.0025 weight % to 0.20 weight %.

12. The castable cement based material according to claim 3, wherein the amount of the rheology modifier (D) in dry solid content with respect to the total binder content is located between 0.000075 weight % to 0.01 weight % (for rheology modifier being an acrylic acid) or 0.0005 weight % to 0.02 weight % (for rheology modifier being a polysaccharide).

13. A method of producing a castable cement based material as defined in claim 2, the method comprising: adding, separately from each other, wax emulsion (A), glycol-based shrinkage reducing agent (B), and water retention agent (C) and/or rheology modifier (D); and performing the adding before, during or after mixing of the other components of the castable cement based material.

14. The method according to claim 13, further comprising the steps of mixing wax emulsion (A), glycol-based shrinkage reducing agent (B), rheology modifier (D) and water retention agent (C) in an admixture, and adding the admixture to other components of the castable cement based material.

15. The method according to claim 14, wherein the component D has a dosage (dry solid content) ranking from 0.015% to 0.2% in weight of the admixture containing all the other components A, B, water and C.

16. The method according to claim 14, wherein the dry solid content ratio between components A and component B in weight is typically located between 0.2 and 1.0.

Description

EXAMPLES

(1) Examples 1-10 are provided for concrete screed and mortar according to the first and second embodiment of the presently disclosed subject matter and mortars (respectively using the components of the internal curing system separately or formulated in an admixture).

(2) The cements used are of type Portland cement type I, II (EN Norms). Sand, fine size aggregates and large size aggregates are either round or crushed.

(3) Mortars have been mixed using standard EN Mortar mixers and concrete samples have been mixed using conventional concrete mixers with capacity from 10 liters to 1 cubic meter.

(4) Flow measurements were performed on cone test and standard spread metallic plate. Strength measurements on mortars were done on 4416 cm standard samples and concrete samples are tested on cubes (151515 cm) or cylinders (diam. 15 cm height 30 cm).

(5) The self curing behavior or the shrinkage resistance was measured using cracking tests.

(6) The crack test carried out in the examples that follow was a modification of the norm ASTM C1579-2006 and is shown in table 3.

(7) The crack test is an evaluation of the plastic shrinkage of mortar or concrete in severe conditions of curing: high temperature (about 40 C.) and dry environment (11-15% RH) and forced strong ventilation (about 5 m/sec).

(8) The test was done by casting a concrete or a mortar in a 38 cm24 cm7 in a mold and placing the mold in a wood hot box (environmental chamber) for 24 hours. A stress riser, made of steel, with internal restraint was placed at the bottom of the mold.

(9) Before placing the molds in the hot box, a surface finishing has to be made, normally by a trowel or a metal straightedge.

(10) In the hot box, two heating fans were used to produce a temperature of about 40 C. and a air speed of about 5 m/sec on the top surface of the molds placed inside.

(11) After 24 h from initial mixing, the area of the cracks that form on the surface was registered. The length and the width of the cracks were measured to calculate the area of the cracks.

(12) Instead of registering the area of the cracks, the minimum and maximum width of the central crack can be measured, which provides a range of the width appeared on the surface of the mortar/concrete.

(13) Comparison of the modified crack test with the norm is shown in Table 3:

(14) TABLE-US-00003 TABLE 3 description of the modified crack test used to characterize the resistance to shrinkage and the effect of the internal curing system. ASTM C1579 Modified crack test Use Fiber reinforced concrete (FRC) All types of mortar and concrete Dimension of the 2 times 56 35.5 10 cm 3 times 38 24 7 cm or test panels 1 time 77 44 7 cm Big stress height 6.35 cm 4.50 cm Hot box Monitor systems of evaporation rate, air flow, No monitor systems setting time Hot box for 2 panels test Hot box for 3 panels test Temperature 36 C. 42 C. Relative Humidity 30% 10% Wind velocity to have an evaporation rate of 1.0 Kg/m2 h 5-7 m/s Procedure Test stops at the final setting time and the Test stops at 24 h. panels test are stored until 24 h at 20 C. under plastic sheets. Results Cracking reduction ratio (CRR) at 24 h: Width range of cracking at (1 ((average crack width of FRC mix)/ 24 h (average crack width of control mix))) 100

(15) The ring test is t is a modification of the standard ring test: ASTM C1581-04.

(16) This method determines the age of cracking and induced tensile stress characteristics of mortar and concrete specimens under restrained shrinkage.

(17) A sample of freshly mixed mortar or concrete is compacted in a circular mold around a steel ring. The restrained shrinkage behavior of concrete or mortar from the time of demolding is monitored continuously by a system of strain gauges that measures the deformation of the material in time. Cracking of the test specimen is indicated by a sudden variation of the displacement value recorded by the strain gauges.

(18) The age at cracking indicates the materials resistance to cracking under restrained shrinkage.

(19) The test enables a measurement of the material deformation coupled with cracking behavior. The apparatus used I a steel mold consisting in a steel base, an inner steel ring and an outer ring (composed of 2 parts).

(20) For mortar: Mold: 16 mm thickness Inner ring: 106 mm internal diameter; 130 mm external diameter; 67 mm height Steel base: 82 mm internal diameter; 162 mm external diameter; 20 mm height Outer ring: 162 mm internal diameter; 87 mm height

(21) For concrete: Mold: 40 mm thickness Inner ring: 294.6 mm internal diameter; 320.1 mm external diameter; 165 mm height Steel base: 400.1 mm internal diameter; 460 mm external diameter; 15 mm height Outer ring: 400 mm internal diameter; 165 mm height

(22) Procedure used: Oil the surface of the molds and cast the material into them. At the time of demolding, remove the two parts of the outer ring and the mold base from the concrete or mortar ring. Seal the bottom of the ring with paraffin wax or an adhesive aluminum foil tape. Place the ring in a flat support and glue the gauges (2-3). Seal the top with the same sealing agent use for the bottom. This operation allows having the drying of the material only from the external surface of the ring. Start the record of the gauges (one measurement every 5-30 minutes) A sudden decrease in the displacement measurement indicates cracking. The sudden decrease is usually about 10 microns of displacement for mortar specimen and about 2-6 microns of displacement for concrete specimen. The text is stopped at 28 days if no cracks were detected.

(23) Examples are provided with various content of binders and various dosages of the components of the internal curing system and various type and contents of aggregates. For each example provided, the same mix design yet containing no internal curing system was also tested to have a reference for each of the examples.

(24) The examples show typical mix designs to build exposed castable cement based material (pavements, walls, slabs, faades, floors, etc.).

Example 1: Mortar Formulation with and without Internal Curing System (System (Components A and B Added Separately from Each Other to the Castable Cement Based Material)

(25) TABLE-US-00004 EXAMPLE 1 Material Unit Reference 1-1 Example 1-1 Example 1-2 Cement kg/m.sup.3 of castable material 450 450 450 Cement Type Type I Type I Type I Fly ash content kg/m.sup.3 of castable material 0 0 0 Total binder content kg/m.sup.3 of castable material 450 450 450 Total water kg/m.sup.3 of castable material 225 201 201 w/b Kg/Kg of total binder per m.sup.3 0.5 0.45 045 of castable material Volume of paste Liters/m.sup.3 of castable material 367 343 343 Plasticizers/superplasticizers Weight % solid dry content of 1.1 1.3 1.3 the total binder content Other Weight % solid dry content of 0 0 0 the total binder content A paraffin based wax Weight % solid dry content, of 0 0.4 0.35 emulsion the total binder content B Glycol based component Weight % solid dry content of 0 0.8 0.53 the total binder content B Glycol type Hexylene Hexylene C water retention Weight % solid dry content, of 0 0 0 component the total binder content Water retention type D rheology modifier Weight % solid dry content, 0 0 0 of the total binder content D rheology modifier type Sand kg/m.sup.3 of castable material 1350 1350 1350 Fine aggregates gravel kg/m.sup.3 of castable material 0 0 0 4/8 round Coarse aggregates gravel kg/m.sup.3 of castable material 0 0 0 8/16 round Results Measurement Unit Value Value value Slump flow mm 160 160 160 Strength at 28 days mm Restrained shrinkage Ring hours 16 41 30 (time of crack)

Example 2: Concrete Formulation with and without Internal Curing System (Components A and B Added Separately from Each Other to the Castable Cement Based Material)

(26) TABLE-US-00005 EXAMPLE 2 Material Unit Reference 2-1 Example 2-1 Cement kg/m.sup.3 of castable material 350 350 Cement Type Type II Type II Fly ash content kg/m.sup.3 of castable material 0 0 Total binder content kg/m.sup.3 of castable material 350 350 Total water kg/m.sup.3 of castable material 191 191 w/b Kg/Kg of total binder per m3 of castable 0.5 0.5 material Volume of paste Liters/m.sup.3 of castable material 307 307 Plasticizers/superplasticizers Weight % solid dry content of the total binder 0.8 0.8 content A paraffin based wax Weight % solid dry content, of the total binder 0 0.08 emulsion content B Glycol based component Weight % solid dry content of the total binder 0 0.28 content B Glycol type Hexylene C water retention Weight % solid dry content, of the total binder 0 0 component content Water retention type D rheology modifier Weight % solid dry content, of the total 0 0 binder content D rheology modifier type Sand kg/m.sup.3 of castable material 1120 1120 Fine aggregates gravel kg/m.sup.3 of castable material 448 448 4/8 round Coarse aggregates gravel kg/m.sup.3 of castable material 672 672 8/16 round Results Measurement Unit Value Value Slump Flow/Class Mm/ 550/SF1 620/SF1 Strength at 28 days mm 64 63.5 Restrained shrinkage Ring hours 174 >600 (time of crack)

Example 3: Concrete Formulation with and without Internal Curing System (Components A and B Added Separately from Each Other to the Castable Cement Based Material)

(27) TABLE-US-00006 EXAMPLE 3 Material Unit Reference 3-1 Example 3-1 Cement kg/m.sup.3 of castable material 450 450 Cement Type Type I Type I Fly ash content kg/m.sup.3 of castable material 0 0 Total binder content kg/m.sup.3 of castable material 450 450 Total water kg/m.sup.3 of castable material 225 200 w/b Kg/Kg of total binder per m.sup.3 of 0.5 0.44 castable material Volume of paste Liters/m.sup.3 of castable material 367 343 Plasticizers/superplasticizers Weight % solid dry content of the 1.1 1.75 total binder content A paraffin based wax Weight % solid dry content, of the 0 0.55 emulsion total binder content B Glycol based component Weight % solid dry content of the 0 0.6 total binder content B Glycol type Hexylene C water retention Weight % solid dry content, of the 0 0.07 component total binder content Water retention type polysaccharide D rheology modifier Weight % solid dry content, of the 0 0 total binder content D rheology modifier type Sand kg/m.sup.3 of castable material 1350 1350 Fine aggregates gravel kg/m.sup.3 of castable material 0 0 4/8 round Coarse aggregates gravel kg/m.sup.3 of castable material 0 0 8/16 round Results Measurement Unit Value Value Slump Flow mm 160 160 Restrained shrinkage Ring hours 16 49 (time of crack)

Example 4: Screed Formulation with and without Internal Curing System (Components A and B Added Separately from Each Other to the Castable Cement Based Material)

(28) TABLE-US-00007 EXAMPLE 4 Material Unit Reference 4-1 Example 4-1 Cement kg/m.sup.3 of castable material 500 500 Cement Type Type II Type II Fly ash content kg/m.sup.3 of castable material 300 300 Total binder content kg/m.sup.3 of castable material 800 800 Total water kg/m.sup.3 of castable material 320 320 w/b Kg/Kg of total binder per m.sup.3 of castable 0.4 0.4 material Volume of paste Liters/m.sup.3 of castable material 637 637 Plasticizers/superplasticizers Weight % solid dry content of the total binder 0.5 0.5 content A paraffin based wax Weight % solid dry content, of the total binder 0 0.4 emulsion content B Glycol based component Weight % solid dry content of the total binder 0 1.39 content B Glycol type Hexylene C water retention Weight % solid dry content, of the total binder 0 0.2 component content Water retention type polysaccharide D rheology modifier Weight % solid dry content, of the total 0 0 binder content D rheology modifier type Sand kg/m.sup.3 of castable material 1140 1140 Fine aggregates gravel kg/m.sup.3 of castable material 0 0 4/8 round Coarse aggregates gravel kg/m.sup.3 of castable material 0 0 8/16 round Results Measurement Unit Value Value Restrained shrinkage Ring days 3 >28 (time of crack) Plastic shrinkage crack test Presence of cracks/crack width (mm) Yes/1.8 No

Example 5: Concrete Formulation with and without Internal Curing System (Components A and B Added Separately from Each Other to the Castable Cement Based Material)

(29) TABLE-US-00008 EXAMPLE 5 Material Unit Reference 5-1 Example 5-1 Cement kg/m.sup.3 of castable material 310 310 Cement Type Type II Type II Fly ash content kg/m.sup.3 of castable material 80 80 Total binder content kg/m.sup.3 of castable material 390 390 Total water kg/m.sup.3 of castable material 183 183 w/b Kg/Kg of total binder per m.sup.3 of castable 0.47 0.47 material Volume of paste Liters/m.sup.3 of castable material 326 326 Plasticizers/superplasticizers Weight % solid dry content of the total binder 0.53 0.53 content A paraffin based wax Weight % solid dry content, of the total binder 0 0.39 emulsion content B Glycol based component Weight % solid dry content of the total binder 0 1.39 content B Glycol type Hexylene C water retention Weight % solid dry content, of the total binder 0 0.02 component content Water retention type polysaccharide D rheology modifier Weight % solid dry content, of the total 0 0 binder content D rheology modifier type Sand kg/m.sup.3 of castable material 781 781 Fine aggregates gravel kg/m.sup.3 of castable material 375 375 4/8 round Coarse aggregates gravel kg/m.sup.3 of castable material 720 720 8/16 round Results Measurement Unit Value Value Restrained shrinkage Ring hours 7 49 (time of crack) Plastic shrinkage crack test Presence of cracks/crack width (mm) YES/2 YES/0.2

Example 6: Screed Formulation with and without Internal Curing System in a Formulated Admixture (Component A, B and D Added Jointly)

(30) TABLE-US-00009 EXAMPLE 6 Material Unit Reference 6-1 Example 6-1 Example 6-2 Cement kg/m.sup.3 of castable material 375 375 375 Cement Type CEM I CEM I CEM I Fly ash content kg/m.sup.3 of castable material 0 0 0 Total binder kg/m.sup.3 of castable material 375 375 375 Total water kg/m.sup.3 of castable material 182 182 182 w/b Kg/Kg of total binder per m.sup.3 of 0.48 0.48 0.48 castable material Volume of paste Liters/m.sup.3 of castable material 301 301 301 Plasticizers/superplasticizers Weight % solid dry content of 2.15 2.15 2.15 the total binder content A paraffin based wax Weight % solid dry content, of 0 0.195 0.325 emulsion the total binder content B Glycol based component Weight % solid dry content of 0 0.7 1.16 the total binder content B Glycol type Hexylene Hexylene C water retention Weight % solid dry content, of 0 0.009 0.015 component the total binder content Water retention type Polysaccharide Polysaccharide D rheology modifier Weight % solid dry content, of 0 0.00040% 0.0007% the total binder content D rheology modifier type acrylic acid acrylic acid Sand kg/m.sup.3 of castable material 1050 1050 1050 Fine aggregates gravel kg/m.sup.3 of castable material 729 729 729 4/12.5 round Coarse aggregates gravel kg/m.sup.3 of castable material 0 0 0 8/16 round Results Measurement Unit Value Value value Slump flow mm 240 220 230 Strength at 28 days Mpa 29.67 27.35 23.83 Plastic shrinkage /mm YES/2 YES/0.2 NO/ cracks/width in mm

Example 7: Screed Formulation with and without Internal Curing System in a Formulated Admixture (Component A, B and D Added Jointly)

(31) TABLE-US-00010 EXAMPLE 7 Material Unit Reference 7-1 Example 7-1 Cement kg/m.sup.3 of castable material 300 300 Cement Type Type II Type II Fly ash content kg/m.sup.3 of castable material 230 230 Total binder kg/m.sup.3 of castable material 530 530 Total water kg/m.sup.3 of castable material 191 191 w/b Kg/Kg of total binder per m.sup.3 of castable 0.36 0.36 material Volume of paste Liters/m.sup.3 of castable material 406 406 Polypropylene fibers Weight % solid dry content of the total 0.17 0.17 binder content Plasticizers/superplasticizers Weight % solid dry content of the total 0.62 0.7 binder content A paraffin based wax Weight % solid dry content, of the total 0 0.42 emulsion binder content B Glycol based component Weight % solid dry content of the total 0 1.38 binder content B Glycol type Hexylene C water retention Weight % solid dry content, of the total 0 0 component binder content Water retention type D rheology modifier Weight % solid dry content, of the total 0 0.0015 binder content D rheology modifier type acrylic acid Sand kg/m.sup.3 of castable material 1050 1050 Fine aggregates gravel 2/8 kg/m.sup.3 of castable material 613 624 round Coarse aggregates gravel kg/m.sup.3 of castable material 0 0 8/16 round Results Measurement Unit Value Value Slump flow mm 230 220 Strength at 28 days Mpa 27.53 26.15 Restrained shrinkage Ring days 7 >28 (time of crack) Plastic shrinkage /mm YES/0.5 NO/ cracks/width in mm

Example 8: Mortar Formulation with and without Internal Curing System in a Formulated Admixture (Component A, B, C and D Added Jointly)

(32) TABLE-US-00011 EXAMPLE 8 Material Unit Reference 8-1 Example 8-1 Cement kg/m.sup.3 of castable material 450 450 Cement Type Type I Type I Fly ash content kg/m.sup.3 of castable material 0 0 Total binder kg/m.sup.3 of castable material 450 450 Total water kg/m.sup.3 of castable material 199 199 w/b Kg/Kg of total binder per m.sup.3 of castable 0.44 0.44 material Volume of paste Liters/m.sup.3 of castable material 341 341 Plasticizers/superplasticizers Weight % solid dry content of the total 1.1 1.3 binder content A paraffin based wax Weight % solid dry content, of the total 0 0.26 emulsion binder content B Glycol based component Weight % solid dry content of the total 0 0.53 binder content B Glycol type Hexylene C water retention Weight % solid dry content, of the total 0 0.53 component binder content Water retention type Polysaccharide D rheology modifier Weight % solid dry content, of the total 0 0.0005 binder content D rheology modifier type acrylic acid Sand kg/m.sup.3 of castable material 1350 1350 Fine aggregates gravel 2/8 kg/m.sup.3 of castable material 0 0 round Coarse aggregates gravel kg/m.sup.3 of castable material 0 0 8/16 round Results Measurement Unit Value Value Slump flow mm 160 160 Restrained shrinkage Ring hours 25 73 (time of crack) Plastic shrinkage /mm YES/0.5 NO/ cracks/width in mm

Example 9: Concrete Formulation with and without Internal Curing System (Components A, B, C and D) Added Jointly to the Castable Cement Based Material)

(33) TABLE-US-00012 EXAMPLE 9 Material Unit Reference 9-1 Example 9-1 Cement kg/m.sup.3 of castable material 230 230 Cement Type Type II Type II Fly ash content kg/m.sup.3 of castable material 110 110 Total binder content kg/m.sup.3 of castable material 340 340 Total water kg/m.sup.3 of castable material 183 184 w/b Kg/Kg of total binder per m.sup.3 of castable 0.54 0.54 material Volume of paste Liters/m.sup.3 of castable material 360 360 Plasticizers/superplasticizers Weight % solid dry content of the total binder 0.88 1.39 content Other Weight % solid dry content of the total binder 0 0 content A paraffin based wax Weight % solid dry content, of the total binder 0 0.3 emulsion content B Glycol based component Weight % solid dry content of the total binder 0 1.07 content B Glycol type Hexylene C water retention Weight % solid dry content, of the total binder 0 0.014 component content Water retention type polysaccharide D rheology modifier Weight % solid dry content, of the total 0 0.0006 binder content D rheology modifier type acrylic acid Sand kg/m.sup.3 of castable material 924 922 Fine aggregates gravel kg/m.sup.3 of castable material 398 398 2/8 round Coarse aggregates gravel kg/m.sup.3 of castable material 488 488 8/16 round Results Measurement Unit Value Value Restrained shrinkage Ring days 6 15 (time of crack) Plastic shrinkage crack test Presence of cracks/crack width (mm) YES/2 NO/

Example 10: Concrete Formulation with and without Internal Curing System (Components A, B, C and D) Added Jointly to the Castable Cement Based Material)

(34) TABLE-US-00013 Example 10 Material Unit Reference 10-1 Example 10-1 Cement kg/m.sup.3 of castable material 290 290 Cement Type Type I Type I Inert filler kg/m.sup.3 of castable material 120 120 Type of filler microsilica microsilica Total binder kg/m.sup.3 of castable material 290 290 Total water kg/m.sup.3 of castable material 205 205 w/b Kg/Kg of total binder per m.sup.3 of 0.71 0.71 castable material Volume of paste Liters/m.sup.3 of castable material 341 341 Plasticizers/superplasticizers Weight % solid dry content of the total 1.53 1.53 binder content A paraffin based wax Weight % solid dry content, of the total 0 0.4 emulsion binder content B Glycol based component Weight % solid dry content of the total 0 1.39 binder content B Glycol type Hexylene C water retention Weight % solid dry content, of the total 0 0.018 component binder content Water retention type polysaccharide D rheology modifier Weight % solid dry content, of the 0 0.0008 total binder content D rheology modifier type acrylic acid Sand kg/m.sup.3 of castable material 836 813 Fine aggregates gravel 4/10 kg/m.sup.3 of castable material 846 823 round Coarse aggregates gravel kg/m.sup.3 of castable material 0 0 8/16 round Results Measurement Unit Value Value Slump flow/Class mm/ 720/SF2 690/SF2 Restrained shrinkage Ring Days 14 >28 (time of crack) Plastic shrinkage crack test Presence of cracks/crack width (mm) YES/1 YES/0.1

(35) It can be seen from the various examples of mix designs for mortars, screeds and concrete that the castable cement based material according to some embodiments all show shrinkage resistances and cracking resistance that are much higher than the respective same castable cement based material that does not contain the internal curing system (examples 1-10).

(36) Example 7 evidences that a screed formulation according to some embodiments (example 7-1) and containing polypropylene fibers that are known to enhance the cracking resistance is having a substantial shrinkage crack resistance enhancement with respect to the same screed mix design containing the same amount of polypropylene fibers without the internal curing system (reference 7.1).

(37) Some embodiments enable the production of shrinkage and shrinkage crack resistance castable material based on cement and to avoid either complicated chemicals that would have detrimental influence on either the final strength, the consistency the workability retention of the setting time of such material.

(38) Also, some embodiments reduce or eliminate the need for all surface post treatment (sealing, covers, spraying), which are production ineffective, delay the job site and represent a significant cost.

(39) Furthermore, the robustness of some embodiments enables the obtainment of an internal curing system in a formulated admixture that can be transported and stored, enabling to dose all ingredients of the internal curing system from just one container, using one single dosing system and pump.