Patent EP0176290A1 successfully refreshed from Google Patents.
US4465518A
Expired / Lapsed
US
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Process for strengthening soft soil
Assignee: Chiyoda Corp
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Filing: 1982-06-14
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Granted: 1984-08-14
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Expires: 2002-06-14
Abstract
Abstract A high water content soft soil, for example from the sea or river bed, may be improved in strength by incorporating thereinto a finely divided, quenched iron blast furnace slag treated with sulfuric acid, and a Portland cement. The sulfuric acid-treated slag is a product obtained by reacting a finely divided, quenched iron blast furnace slag, such as a water-granulated iron blast furnace slag, with sulfuric acid to convert a part of its calcium components into gypsum.
Inventors
- 👤 Hajime Miyoshi
- 👤 Etsuo Asanagi
- 👤 Osamu Terashima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 02:29
CPC Classifications
C; C09; C09K; C09K17/00; C09K17/02; C09K17/10; C04; C04B; C04B18/00; C04B18/04; C04B18/14; C04B18/141; C04B28/00; C04B28/02; C04B28/04; Y; Y02; Y02W; Y02W30/00; Y02W30/50; Y02W30/91; Y10; Y10S; Y10S106/00; Y10S106/90
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
109 words
A process for improving the strength of a water-saturated soft soil comprising: providing a finely divided, non-crystalline, calcium-containing iron blast furnace slag; treating said slag with an aqueous solution containing 20-500 g sulfuric acid per 1 kg of slag to provide an acid-treated slag (A) with conversion of a part of the calcium content of said slag to gypsum; admixing said acid-treated slag with the soft soil to be treated; and admixing said acid treated slag and the soft soil with (B) a Portland cement to obtain an unconfined compressive strength of the soil greater than that obtained by using comparable amounts of cement, calcium sulfate and unacidified slag.
Claim 2
Dependent Claim
109 words
A process for improving the strength of a water-saturated soft soil comprising: providing a finely divided, non-crystalline, calcium-containing iron blast furnace slag; treating said slag with an aqueous solution containing 20-500 g sulfuric acid per 1 kg of slag to provide an acid-treated slag (A) with conversion of a part of the calcium content of said slag to gypsum; admixing said acid-treated slag with the soft soil to be treated; and admixing said acid treated slag and the soft soil with (B) a Portland cement to obtain an unconfined compressive strength of the soil greater than that obtained by using comparable amounts of cement, calcium sulfate and unacidified slag.
Claim 3
Dependent Claim
23 words
A process as recited in claim 1, wherein the ratio by weight of ingredient (A) to ingredient (B) is about 70/30 to 35/65.
Claim 4
Dependent Claim
19 words
A process as recited in claim 1, wherein the slag has a particle size of 300 μm or less.
Claim 5
Dependent Claim
17 words
A process as recited in claim 3, wherein the slag is a water-granulated iron blast furnace slag.
Claim 6
Dependent Claim
21 words
A process as recited in claim 1, wherein the soft soil is admixed with ingredient (A) before admixture with ingredient (B).
Claim 7
Dependent Claim
20 words
A process as recited in claim 1, wherein the soft soil is admixed with ingredient (A) and ingredient (B) simultaneously.
Claim 8
Dependent Claim
25 words
A process as recited in claim 6, comprising forming an aqueous slurry containing ingredients (A) and (B) and admixing the soft soil with said slurry.
Claim 9
Dependent Claim
32 words
A process as recited in claim 1, further comprising admixing said soft soil with a water-soluble ferrous salt, prior to the addition of ingredient (B), in amount effective to deodorize said soil.
Claim 10
Dependent Claim
25 words
The process of claim 1 wherein about 2-60% of the calcium components of the slag are converted into gypsum by reaction with the sulfuric acid.
Claim 11
Dependent Claim
25 words
The process of claim 1 wherein about 3-35% of the calcium components of the slag are converted into gypsum by reaction of the sulfuric acid.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-14 | 1988-02-13 | 1988-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-14 | 1992-02-13 | 1992-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-14 | 1996-02-13 | 1996-08-14 | $7700.00 | Window Closed / Lapsed |