US4142909A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and composition for controlling contraction in setting cementitious systems through the addition of gas generating agents
Assignee: Construction Products Research Inc
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Filing: 1975-09-11
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Granted: 1979-03-06
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Expires: 1995-09-11
Abstract
Abstract The contraction of aqueous hydraulic cement mixtures is controlled by the addition thereto of a gas generating agent capable of generating gas in the mixture without the addition of activators or other agents. Gas generation may be controlled over an extended period of time so that even slow setting cementitious mixtures may have their shrinkage or contraction inhibited during setting and hardening.
Inventors
- 👤 Robert W. Gaines
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:14
CPC Classifications
C; C04; C04B; C04B24/00; C04B24/16; C04B24/20; C04B22/00; C04B22/0013; C04B24/12; C04B24/123; C04B2111/00; C04B2111/34
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
107 words
A method of controlling contraction of hydraulic cementitious systems during setting and hardening comprising adding to the system a gas generating organic agent having a normal thermal decomposition temperature above the temperatures encountered during the setting and hardening of the hydraulic cementitious system, without activators, capable of chemically generating gas in the system during setting and hardening when liquid for setting and hardening is present therein without the addition of activating agent additives and without specific temperature control other than the ordinary ambient temperature conditions of setting and hardening being necessary for gas generation in an amount effective to counteract the contraction tendency of the cementitious system.
Claim 2
Independent Claim
107 words
A method of controlling contraction of hydraulic cementitious systems during setting and hardening comprising adding to the system a gas generating organic agent having a normal thermal decomposition temperature above the temperatures encountered during the setting and hardening of the hydraulic cementitious system, without activators, capable of chemically generating gas in the system during setting and hardening when liquid for setting and hardening is present therein without the addition of activating agent additives and without specific temperature control other than the ordinary ambient temperature conditions of setting and hardening being necessary for gas generation in an amount effective to counteract the contraction tendency of the cementitious system.
Claim 3
Dependent Claim
23 words
A method as claimed in claim 1 wherein the gas generating organic agent is methyl ethyl ketone peroxide dissolved in an nonaqueous solvent.
Claim 4
Dependent Claim
28 words
A method as claimed in claim 1 wherein the gas generating organic agent is one selected from the group consisting of azodicarbonamide, sodium azodicarboxylate and p-toluene sulfonyl hydrazide.
Claim 5
Dependent Claim
25 words
A method as claimed in claim 3 wherein the effective amount is 0.002-0.1 percent of additive by weight based on the cementitious system nonaqueous constituents.
Claim 6
Dependent Claim
23 words
A method as claimed in claim 1 wherein the gas is capable of being generated for a period of at least 5 hours.
Claim 7
Dependent Claim
113 words
A cementitious composition which, when mixed with water, is capable of setting into a hard mass without substantial shrinkage during setting and hardening comprising a hydraulic cement mixture and a gas generating organic agent having a normal thermal decomposition temperature above the temperatures encountered during the setting and hardening of the hydraulic cementitious system, without activators, capable of chemically generating gas in the presence of hydraulic cement and water during setting and hardening without the presence of other constituents and without specific temperature control other than the ordinary ambient temperature conditions of setting and hardening being necessary for gas generation in an amount effective to counteract the shrinkage tendency of the cementitious composition.
Claim 8
Dependent Claim
113 words
A cementitious composition which, when mixed with water, is capable of setting into a hard mass without substantial shrinkage during setting and hardening comprising a hydraulic cement mixture and a gas generating organic agent having a normal thermal decomposition temperature above the temperatures encountered during the setting and hardening of the hydraulic cementitious system, without activators, capable of chemically generating gas in the presence of hydraulic cement and water during setting and hardening without the presence of other constituents and without specific temperature control other than the ordinary ambient temperature conditions of setting and hardening being necessary for gas generation in an amount effective to counteract the shrinkage tendency of the cementitious composition.
Claim 9
Dependent Claim
24 words
A cementitious composition as claimed in claim 6 wherein the gas generating organic agent is methyl ethyl ketone peroxide dissolved in an nonaqueous solvent.
Claim 10
Dependent Claim
29 words
A cementitious composition as claimed in claim 6 wherein the gas generating organic agent is one selected from the group consisting of axodicarbonamide, sodium azodicarboxylate and p-toluene sulfonyl hydrazide.
Claim 11
Independent Claim
75 words
A method of controlling contraction of hydraulic cementitious systems during setting and hardening comprising adding thereto a hydrogen gas generating agent which is capable of controllably generating hydrogen gas to predictably inhibit shrinkage of the system without specific temperature control other than the ordinary ambient temperature conditions of setting and hardening being necessary for gas generation, the agent consisting of sodium borohydride in an amount effective to counteract the shrinkage tendency of the cementitious system.
Claim 12
Independent Claim
75 words
A method of controlling contraction of hydraulic cementitious systems during setting and hardening comprising adding thereto a hydrogen gas generating agent which is capable of controllably generating hydrogen gas to predictably inhibit shrinkage of the system without specific temperature control other than the ordinary ambient temperature conditions of setting and hardening being necessary for gas generation, the agent consisting of sodium borohydride in an amount effective to counteract the shrinkage tendency of the cementitious system.
Claim 13
Dependent Claim
59 words
A cementitious composition which, when mixed with water, is capable of setting into a hard mass without substantial shrinkage during setting and hardening comprising a hydraulic cement mixture and sodium borohydride in an amount effective to generate gas under ordinary ambient temperature conditions without the addition of an activating agent to counteract the shrinkage tendency of the cementitious system.
Claim 14
Dependent Claim
59 words
A cementitious composition which, when mixed with water, is capable of setting into a hard mass without substantial shrinkage during setting and hardening comprising a hydraulic cement mixture and sodium borohydride in an amount effective to generate gas under ordinary ambient temperature conditions without the addition of an activating agent to counteract the shrinkage tendency of the cementitious system.
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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) | 1982-03-05 | 1982-09-04 | 1983-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-03-05 | 1986-09-04 | 1987-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-03-05 | 1990-09-04 | 1991-03-06 | $7700.00 | Window Closed / Lapsed |