US4031684A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Decorative precast concrete boards and process for producing the same
Assignee: Individual
•
Filing: 1975-11-11
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Granted: 1977-06-28
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Expires: 1995-11-11
Abstract
Abstract Decorative precast concrete boards having a pore-free decorative porcelain-tile-like, hewn-stone-like or relief surface and a porous core layer are provided. Such precast concrete boards are produced by applying inorganic cement mortar containing siliceous volcanic sand called "shirasu" in a flat mold made of an elastomeric material so as to form the pore-free surface and pouring thereon an inorganic concrete mortar containing expanded particles of said siliceous sand as the aggregate. The concrete boards do not suffer efflorescence.
Inventors
- 👤 Tokuhito Shibata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 01:56
CPC Classifications
E; E04; E04C; E04C2/00; E04C2/02; E04C2/04; E04C2/049; B; B28; B28B; B28B1/00; B28B1/008; B28B7/00; B28B7/0064; B28B7/007; C; C04; C04B; C04B28/00; C04B28/02; C04B2111/00; C04B2111/00474; C04B2111/00612
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
100 words
A decorative precast concrete board comprising at least one surface layer and a core layer, the four edges of which recede or are indented toward the back side, said surface layer being made of an inorganic cement mortar containing non-expanded shirasu at least in an amount that said sand occupies at least 30% by weight of the total amount of the dry ingredients, and said core layer being made from an inorganic concrete mortar containing fine hollow spherical expanded shirasu in an amount that said expanded sand occupies 10- 70% by weight of the total amount of the dry ingredients.
Claim 2
Dependent Claim
100 words
A decorative precast concrete board comprising at least one surface layer and a core layer, the four edges of which recede or are indented toward the back side, said surface layer being made of an inorganic cement mortar containing non-expanded shirasu at least in an amount that said sand occupies at least 30% by weight of the total amount of the dry ingredients, and said core layer being made from an inorganic concrete mortar containing fine hollow spherical expanded shirasu in an amount that said expanded sand occupies 10- 70% by weight of the total amount of the dry ingredients.
Claim 3
Dependent Claim
23 words
The decorative precast concrete board as claimed in claim 1, wherein the siliceous volcanic sand contains at least 75% by weight of silica.
Claim 4
Dependent Claim
20 words
The decorative precast concrete board as claimed in claim 2, wherein the core layer has incorporated therein chopped synthetic fiber.
Claim 5
Dependent Claim
46 words
The decorative precast concrete board as claimed in claim 2, wherein the thickness of the surface layer is 5- % of the total thickness of the finished board, and the thickness of the core layer is 95- 80% of the total thickness of the finished board.
Claim 6
Dependent Claim
47 words
The decorative precast concrete board as claimed in claim 4, wherein the inorganic cement mortar for the surface layer contains not less than 50% by weight of shirasu and the inorganic cement mortar for the core layer contains 30- 70% by weight of siliceous volcanic sand (shirasu).
Claim 7
Dependent Claim
44 words
The decorative precast concrete board as claimed in claim 5, wherein the inorganic cement mortar for the surface layer contains not less than 70% by weight of shirasu and the inorganic cement mortar for the core layer contains 50- 40% by weight of shirasu.
References Cited (Backward Citations)
US2703289A
Cited
US3645961A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-06-27 | 1980-12-27 | 1981-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-27 | 1984-12-27 | 1985-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-27 | 1988-12-27 | 1989-06-28 | $7700.00 | Window Closed / Lapsed |