# US 4,398,959 A · Mortar topping with calcium nitrite

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- Number: US 4,398,959 A
- Document ID: US4398959A
- Status: Granted
- Kind: A
- Application number: 06/352,292
- Filed: 1982-02-25
- Granted: 1983-08-16
- Earliest claimed: 1981-04-15
- Assignees: W. R. Grace & Co.
- Inventors: Arnold M. Rosenberg; James M. Gaidis; Howard J. Troffkin
- Web page: https://patentgrep.com/patent/US4398959A

## CPC

- E01D 22/00: Methods or apparatus for repairing or strengthening existing bridges {(electrochemical desalination or re-alkalisation C04B41/00); Methods or apparatus for dismantling bridges}
- C04B 28/02: containing hydraulic cements other than calcium sulfates
- E04G 23/02: Repairing, e.g. filling cracks; Restoring; Altering; Enlarging {(compositions of filling material C04B; strengthening, widening, repairing of bridges E01D22/00; drying damp layers by temporary mechanical ventilation E04B1/7092)}
- E01D: CONSTRUCTION OF BRIDGES, {ELEVATED ROADWAYS} OR VIADUCTS; ASSEMBLY OF BRIDGES (bridges extending between terminal buildings and aircraft for embarking or disembarking passengers B64F1/305; {tracks for special kinds of railways E01B25/00; culverts E01F5/005})
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- E04G: SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS

## Abstract

Reinforced concrete structures often suffer corrosion damage. This damage is repaired by removing the layer of distressed concrete around the metal reinforcement and filling in the removed area with a high content calcium nitrite-containing cement based composition.

## Claims

### Claim 1

A method of inhibiting corrosion of concrete structure containing metal reinforcement elements therein comprising
removing a layer of concrete from said concrete structure and
refilling the removed area of concrete structure with a cement based composition consisting essentially of, in parts by weight, about 5 to 20 parts hydraulic cement, about 10 to 40 parts sand, about 2 to 10 parts water, about 0 to 1 part lime, about 0 to 50 parts aggregate of up to about 0.5 inch diameter, about 0 to 10 parts latex and about 0.5 to 4 parts calcium nitrite, the calcium nitrite being in at least 20 percent by weight of the water content.

### Claim 2 (depends on 1)

The method of claim 1 wherein the layer of concrete removed from said concrete structure contains damaged concrete.

### Claim 3 (depends on 2)

The method of claim 2 wherein the layer of concrete removed is of a depth to substantially expose some of the reinforcement elements.

### Claim 4 (depends on 1, 2, 3)

The method of claim 1, 2 or 3 wherein the lime content of the cement based composition is from 0.1 to 0.5 parts by weight.

### Claim 5 (depends on 1, 2, 3)

The method of claim 1, 2 or 3 wherein the cement based composition consists essentially of, in parts by weight, about 1 part cement, about 2 parts sand, about 0.5 parts water, about 0.1 part calcium nitrite and from 0.1 to 0.5 part lime.

### Claim 6 (depends on 1, 2, 3, 4)

The method of claim 1, 2, 3 or 4 wherein the cement based composition contains about 2 to 10 parts latex of styrene-butadiene or of vinylidene chloride.

### Claim 7 (depends on 1, 2, 3, 4)

The method of claim 1, 2, 3 or 4 wherein the cement based composition contains 10 to 50 parts aggregate of about 0.3 to 0.5 inch diameter.

### Claim 8

A concrete structure capable of inhibiting corrosion comprising
(a) a concrete structure containing metal reinforcement elements therein; said structure being free of calcium nitrite, and
(b) a layer of cement based composition applied over the exposed surface of the concrete structure (a); said cement based composition formed from a mixture consisting essentially of, in parts by weight, about 5 to 20 parts hydraulic cement, about 10 to 40 parts sand, about 2 to 10 parts water, about 0 to 1 part lime, about 0 to 50 parts aggregate of up to about 0.5 inch diameter, about 0 to 10 parts latex and about 0.5 to 4 parts calcium nitrite, the calcium nitrite being in at least 20 percent by weight of the water content.

### Claim 9 (depends on 8)

The structure of claim 8 wherein the cement based composition (b) is formed with from 0.1 to 0.5 part lime.

### Claim 10 (depends on 8)

The structure of claim 8 wherein the cement based composition (b) is formed with from 2 to 10 parts latex of styrene-butadiene or of vinylidene chloride.