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Showing 1-5 of 12 Abstracts search results

Document: 

SP102

Date: 

September 1, 1987

Author(s):

Editor: Frances W. Gibson

Publication:

Symposium Papers

Volume:

102

Abstract:

SP102 As a designer you need the wealth of information presented in "Corrosion, Concrete and Chlorides -- Steel Corrosion in Concrete: Causes and Restraints," a compilation of 11 papers covering the corrosion phenomenon. Prompted by the nationwide corrosion problem with concrete, there have been extensive field and laboratory investigations into the specific phenomena that induce corrosion, methods for identifying the magnitude and extent of corrosion in structures, techniques for stabilizing corrosion once it has begun, and design of structures and concretes so that corrosion will not occur. Presenting an in-depth analysis into a variety of aspects dealing with corrosion, this state-of-the-art publication includes such topics as: the marked influence of chloride in causing corrosion, ways for controlling corrosion by using chloride-free accelerators, the reduction of chloride penetration through the use of pozzolanic blast-furnace slag as an admixture in concrete, and the conductive coating aspects of cathodic protection. "Corrosion, Concrete and Chlorides" provides important answers to a complex problem.

DOI:

10.14359/14218


Document: 

SP102-06

Date: 

September 1, 1987

Author(s):

Sandor Popovics

Publication:

Symposium Papers

Volume:

102

Abstract:

Strength-increasing effects of achloride-free accelerating admixture are investigated on various portland cement pastes, mortars and concretes with or without other admixtures. Although the test results are preliminary in nature, the available experimental evidence shows that this chloride-free accelerator increases significantly the strengths of a wide variety of cementitious compositions including portland cement, epoxy, pozzolans and combinations of these.

DOI:

10.14359/1620


Document: 

SP102-01

Date: 

September 1, 1987

Author(s):

William G. Hime and Bernard Erlin

Publication:

Symposium Papers

Volume:

102

Abstract:

The wide variety of disciplines involved with the corrosion of steel in concrete has caused difficulties in communication. Each discipline has its own terminology; at times two disciplines use conflicting terms or explanations for the same phenomenon. This paper addresses some areas of such confusion, and presents chemical mechanisms to explain half-cell potentials and causes for chloride-induced corrosion. Examples of such corrosion are presented.

DOI:

10.14359/1631


Document: 

SP102-04

Date: 

September 1, 1987

Author(s):

Jens Holm

Publication:

Symposium Papers

Volume:

102

Abstract:

A method for evaluation of the corrosion potential of chemical admixtures is presented. The method allows the direct measurement of the macrocell corrosion current between two layers of electrically connected reinforcing bars embedded in concrete. By ponding the specimens with chloride-free water, the potential of the chemical admixture to instigate corrosion can be evaluated. By using a chloride-containing ponding solution, in particular a 15% NaCl solution, it may be possible to assess the potential corrosion inhibiting effects of certain chemical admixtures. The test method was used to compare the corrosion activity in reinforced concrete slabs containing a normal dosage rate of calcium chloride, plain concrete and concrete containing two dosage rates of a multicomponent calcium nitrate based non-chloride accelerator. Only the slabs containing calcium chloride exhibited corrosion when ponded with tap water. When subjected to cyclic ponding with the salt solution, both the plain concrete and the concrete slabs containing the two dosage rates of the non-chloride accelerator exhibited corrosion. However, the slab containing the higher dosage rate of the non-chloride accelerator exhibited only 25% of the corrosion activity of the other two slabs. It is speculated that this reduction may be the result of corrosion-inhibiting effects of the non-chloride accelerator when it is added at sufficient rates.

DOI:

10.14359/1637


Document: 

SP102-05

Date: 

September 1, 1987

Author(s):

David Chin

Publication:

Symposium Papers

Volume:

102

Abstract:

Two important properties of calcium nitrite are that it is an accelerator and a corrosion inhibitor when used as an admixture in concrete. With its performance as an accelerator enhanced, calcium nitrite can be used as an effective non-corrosive, non-chloride accelerator in normal and fly ash concrete. The calcium nitrite-based accelerator provides good accelera-tion in initial setting times at 50°F (10°C) and 72°F (22°C) produces a significant improvement in compressive strengths at early ages. Electrochemical solution tests can be used to conduct a quick screening test to determine the potential corrosivity of a non-chloride accelerator. Potential and linear polarization resistance measurement tests provide a quick indication regarding the potential corrosivity of a non-chloride accelerator.

DOI:

10.14359/1619


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