1. A method for concrete parts and structures, which comprises:
(i) supplying a first concrete composition based on a quick binder containing:
60 to 95% Portland cement;
5 to 40% curing accelerator system based on Al2O3 alumina, CaO lime and SO3 sulfate;
a retarder system; and
a superplasticizer containing a polyphosphonate polyox type polymer, or a mixture of polymers of the type polyphosphonate polyox and polycarboxylate polyox;
then
(ii) adding a releaser system to form a second concrete composition; and
(iii) pouring this second concrete composition in a concrete form.
2. A method according to claim 1, wherein the curing accelerator system contains, in weight:
Al2O3 alumina:
35 to 50%
CaO lime:
10 to 50%
Sulfate (expressed in S03):
\u2002\u20095 to 30%.
3. A method according to claim 1, wherein the curing accelerator system is based on calcium aluminate and calcium sulfate.
4. A method according to claim 1, wherein the sulfate is selected among the metallic, alkaline, alkaline-earth sulfates, the organic sulfates or the mixtures thereof.
5. A method according to claim 1, wherein the step (i) is a wet mixing step wherein the first primary composition is prepared and which contains the following steps:
(a) a concrete composition is prepared containing, on the base of the quick binder:
60 to 95% Portland cement;
the retarder system; and
the superplasticizer;
then
(b) adding, on the base of the quick binder:
5 to 40% curing accelerator system.
6. A method according to claim 1, wherein the step (ii) is implemented at least 10 minutes, preferably at least 60 minutes but no later than 8 hours after wet mixing of the step (i).
7. A method according to claim 1, wherein the step (ii) is implemented immediately before the concrete pouring step (iii).
8. A method according to claim 1, including the following steps:
(i) supplying by wet mixing in a ready-mix plant a first concrete composition based on a quick binder;
then
(ii) adding a releaser system; and
(iii) pouring the concrete immediately after the releaser system addition step (ii).
9. A method according to claim 7, wherein the step (ii) is implemented in a truck-mixer.
10. A method according to claim 1, wherein the step (iii) comprising pouring the second concrete composition in a concrete form is conducted with a second concrete composition exhibiting a slump test value ranging between 15 and 24 cm, preferably between 18 and 22 cm.
11. A method according to claim 1, wherein the step (iii) comprising pouring the second concrete composition in a concrete form is conducted with a second concrete composition exhibiting a slumpflow value ranging between 580 and 750 mm, preferably between 650 and 750 mm.
12. A method according to claim 1, for the realisation of concrete shells or concrete slabs.
13. A method according to claim 1, wherein the first concrete composition contains:
70 to 85% Portland cement;
15 to 25% curing accelerator system;
the retarder system; and
the superplasticizer.
14. A method according to claim 1, wherein the Portland cement is a cement complying with the EN 197-1 standard, advantageously a quick cement (so-called R type), preferably crushed to a fineness of at least 4000 cm2g, such as HIR (high initial strength), for instance CEM1 52.5 N or R cement, 32.5, 32.5 R, 42.5 or 42.5 R type CEM2, with the ratio of soluble alkalines preferably lower than 1% in weight expressed in Na2O equivalent.
15. A method according to claim 1, wherein the curing accelerator system is based on calcium aluminate and calcium sulfate in semi-hydrate, dihydrate or anhydrite form.
16. A method according to claim 1, wherein the calcium aluminate used includes CA andor C3A andor C12A7 phases.
17. A method according to claim 3, wherein the mass ratio between the calcium aluminate and the calcium sulfate ranges between 1:4 and 4:1, preferably between 2:1 and 1:2.
18. A method according to claim 1, wherein the retarder system is carboxylic or boric acid, in particular citric or tartaric or gluconic acid, wherein acid is optionally in the form of a salt, in combination optionally with another mineral additive providing or using calcium, for instance sodium, potassium, lithium, strontium or barium carbonates or fluorides, or still calcium complexing agents such as EDTA.
19. A method according to claim 1, wherein the amount of the retarder system, in weight relative to the cumulated weight of the Portland cement and of the curing accelerator system, ranges between 0.05 and 5% and preferably 0.1 and 1%.
20. A method according to claim 1, wherein the amount of the superplasticizer, in weight relative to the cumulated weight of the Portland cement and of the curing accelerator system, ranges between 0.5 and 5%, preferably 1 and 3%.
21. A method according to claim 1, wherein the trigger is selected among the group consisting of:
aqueous suspension containing (i) at least one calcium aluminate, (ii) from 0.5 to 4%, preferably from 0.6 to 2.3%, in weight relative to the total weight of the calcium aluminate(s), of a setting inhibitor of the aluminous cements, and (iii) at least one settling-preventing agent;
a transition alumina;
an alumina hydroxide gel;
a mixture thereof.
22. A method according to claim 1, wherein the amount of the releaser, in weight relative to the cumulated weight of the Portland cement and of the curing accelerator system, is 1 to 10%, preferably 2 to 5%.
23. A method according to claim 1, wherein the second concrete composition exhibits a compression mechanical strength RC of at least 1 MPa, 2 h after the step (ii).
24. A method according to claim 1, wherein the second concrete composition exhibits a compression mechanical strength RC of at least 1 MPa, 4 h after the step (i).
25. A method according to claim 1, wherein the first concrete composition has a workability keeping time of at least 1 hour after step (i).
26. A method according to claim 1, wherein the second concrete composition has a workability keeping time of at least 30 minutes after step (ii).
27. (canceled)
28. A preparation of a first quick concrete composition intended for being added a releaser system for a method of preparation of concrete parts and structures, such as defined in claim 1.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An additive manufacturing system comprising:
a laser device configured to generate a laser beam;
a first scanning device configured to selectively direct the laser beam across a powder bed, wherein the laser beam generates a melt pool in the powder bed; and
an optical system comprising:
an optical detector configured to detect electromagnetic radiation generated by the melt pool; and
a second scanning device configured to direct electromagnetic radiation generated by the melt pool to said optical detector.
2. The system in accordance with claim 1, wherein said optical system is configured to receive electromagnetic radiation from an observation zone, said second scanning device configured to scan the observation zone across the powder bed to track the melt pool.
3. The system in accordance with claim 1 further comprising a processor coupled to said second scanning device, said processor configured to control said second scanning device synchronously with said first scanning device.
4. The system in accordance with claim 1, wherein said second scanning device comprises at least one mirror and at least one actuator operatively coupled to said at least one mirror.
5. The system in accordance with claim 4, wherein said mirror is a first mirror, and said first scanning device comprises a second mirror, wherein said first mirror comprises a first reflective coating having a first reflectance spectrum, and said second mirror comprises a second reflective coating having a second reflectance spectrum different from the first reflectance spectrum.
6. The system in accordance with claim 5, wherein the first reflective spectrum corresponds to a wavelength of electromagnetic radiation detectable by said optical detector, and the second reflective spectrum corresponds to a wavelength of the laser beam.
7. The system in accordance with claim 1, wherein said optical detector comprises at least one of a photomultiplier tube, a photodiode, an infrared camera, a CCD camera, a pyrometer, and a CMOS detector.
8. The system in accordance with claim 1, wherein said laser device is configured to generate a laser beam having a power of at least approximately 400 watts.
9. The system in accordance with claim 1, wherein the laser beam travels along an optical path from said laser device to the powder bed, wherein the optical path is free of dichroic beam splitters.
10. The system in accordance with claim 1, wherein the additive manufacturing system is a direct metal laser melting system.
11. A method for monitoring an additive manufacturing process, said method comprising:
directing a laser beam across a powder bed using a first scanning device to generate a melt pool in the powder bed; and
directing electromagnetic radiation generated by the melt pool to an optical detector using a second scanning device.
12. The method in accordance with claim 11, wherein the optical detector receives electromagnetic radiation from an observation zone, and directing electromagnetic radiation generated by the melt pool comprises scanning the observation zone of the optical detector across the powder bed to track the melt pool.
13. The method in accordance with claim 11 further comprising controlling the second scanning device synchronously with the first scanning device.
14. The method in accordance with claim 11, wherein the second scanning device includes a mirror and an actuator operatively coupled to the mirror, wherein directing electromagnetic radiation generated by the melt pool comprises rotating the mirror using the actuator such that electromagnetic radiation generated by the melt pool is deflected by the mirror to the optical detector.
15. The method in accordance with claim 11, wherein generating a laser beam comprises generating a laser beam having a power of at least approximately 400 watts.
16. An optical system for use in an additive manufacturing system, said system comprising:
an optical detector configured to detect electromagnetic radiation generated by a melt pool; and
a dedicated scanning device configured to direct electromagnetic radiation generated by the melt pool to said optical detector.
17. The system in accordance with claim 16, wherein said optical system is configured to receive electromagnetic radiation from an observation zone, said dedicated scanning device configured to scan the observation zone across the powder bed to track the melt pool.
18. The system in accordance with claim 16, wherein said dedicated scanning device comprises at least one mirror and at least one actuator operatively coupled to said at least one mirror.
19. The system in accordance with claim 18, wherein said at least one mirror includes a reflective coating having a reflectance spectrum that corresponds to electromagnetic radiation detectable by said optical detector.
20. The system in accordance with claim 16, wherein said optical detector comprises at least one of a photomultiplier tube, a photodiode, an infrared camera, a CCD camera, a pyrometer, and a CMOS detector.