US3883361A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Portland cements
Assignee: Associated Portland Cement Manufacturers Ltd
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Filing: 1973-10-04
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Granted: 1975-05-13
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Expires: 1993-10-04
Abstract
Abstract A cement of the Portland type comprising at least a proportion of a clinker ground to a specific surface of 250-550 M2/Kg and having a microstructure predominantly comprising alite crystals containing globular inclusions of free lime, the free lime content of the clinker being at least 2% by weight and predominantly formed by the globular inclusions in the alite crystals.
Inventors
- 👤 Harry Wilfred Wallace Pollitt
- 👤 Arthur William Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:11
CPC Classifications
C; C04; C04B; C04B7/00; C04B7/02
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
53 words
AN EXPANSIVE CEMENT OF THE PORTLAND TYPE COMPRISING A CLINKER GROUND TO A SPECIFIC SURFACE OF 250-550M2/KG AND COMPOSED PREDOMINANTLY OF ALITE WITH AT LEAST 2 PERCENT BY WEIGHT BASED ON THE CLINKER OF FREE LIME THE MAJOR PROPORTION OF WHICH IS IN THE FORM OF GLOBULAR INCLUSIONS ENCAPSULATED WITHIN INDIVIDUAL ALITE CRYSTALS.
Claim 2
Dependent Claim
53 words
AN EXPANSIVE CEMENT OF THE PORTLAND TYPE COMPRISING A CLINKER GROUND TO A SPECIFIC SURFACE OF 250-550M2/KG AND COMPOSED PREDOMINANTLY OF ALITE WITH AT LEAST 2 PERCENT BY WEIGHT BASED ON THE CLINKER OF FREE LIME THE MAJOR PROPORTION OF WHICH IS IN THE FORM OF GLOBULAR INCLUSIONS ENCAPSULATED WITHIN INDIVIDUAL ALITE CRYSTALS.
Claim 3
Dependent Claim
18 words
A cement composition comprising a mixture of expansive cement as defined in claim 1 and ordinary Portland cement.
Claim 4
Dependent Claim
20 words
A cement according to claim 1, wherein the clinker has a free lime content of up to 20% by weight.
Claim 5
Dependent Claim
19 words
A cement according to claim 3, wherein the clinker has a free lime content of 3%- 12% by weight.
Claim 6
Dependent Claim
18 words
A cement according to claim 4, wherein the free lime content of the cement is 4%-6% by weight.
Claim 7
Dependent Claim
79 words
An expansive cement of the Portland type comprising an intimate mixture of (A) at least 40 parts by weight of a clinker ground to a specific surface of 250 - 550m2/kg and composed predominantly of alite crystals with at least 2 percent by weight based on the clinker of free lime the major proportion of the free lime being encapsulated inside the alite crystals as globular inclusions therein, with (B) 60 parts by weight of an ordinary Portland cement.
Claim 8
Dependent Claim
79 words
An expansive cement of the Portland type comprising an intimate mixture of (A) at least 40 parts by weight of a clinker ground to a specific surface of 250 - 550m2/kg and composed predominantly of alite crystals with at least 2 percent by weight based on the clinker of free lime the major proportion of the free lime being encapsulated inside the alite crystals as globular inclusions therein, with (B) 60 parts by weight of an ordinary Portland cement.
Claim 9
Independent Claim
98 words
A method of producing a Portland type cement having expansive properties, comprising: forming a mixture of (A) argillaceous material and (B) calcareous material at least 2 percent by weight of which is calcium sulphate, in proportions of (A) and (B) favoring the formation on firing of C3S with at least 2 percent of free lime; firing the mixture until a clinker is formed having a microstructure composed predominantly of alite crystals encapsulating the major proportion of said free lime as globular inclusions within individual alite crystals; and grinding the clinker to a specific surface of 250 - 550m2/kg.
Claim 10
Independent Claim
98 words
A method of producing a Portland type cement having expansive properties, comprising: forming a mixture of (A) argillaceous material and (B) calcareous material at least 2 percent by weight of which is calcium sulphate, in proportions of (A) and (B) favoring the formation on firing of C3S with at least 2 percent of free lime; firing the mixture until a clinker is formed having a microstructure composed predominantly of alite crystals encapsulating the major proportion of said free lime as globular inclusions within individual alite crystals; and grinding the clinker to a specific surface of 250 - 550m2/kg.
Claim 11
Dependent Claim
28 words
A method according to claim 7 wherein at least 40 parts by weight of said clinker are interground with 60 parts by weight of ordinary Portland cement clinker.
Claim 12
Dependent Claim
29 words
A method according to claim 7, wherein at least 40 parts by weight of said clinker after grinding are blended with 60 parts by weight of ordinary Portland cement.
Claim 13
Dependent Claim
23 words
A method according to claim 7, wherein the lime saturation factor of the raw material mix is in the range 0.90 - 1.30.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |