International Concrete Abstracts Portal

Showing 1-5 of 17 Abstracts search results

Document: 

SP64-09

Date: 

July 1, 1980

Author(s):

George C. Hoff and Katharine Mather

Publication:

Symposium Papers

Volume:

64

Abstract:

Samples of Type K shrinkage-compensating cement from all 17 mills producing that cement in 1974 were obtained and evaluated for compliance with a proposed specification for these cements. The cements were also evaluated for specific gravity, fineness, heat of hydration, and expansion and drying shrinkage in mortars. Concretes were also made with the cements and evaluated for air content, slump, compressive strength, expansion, and drying shrinkage. In general most cements had little trouble meeting the specification requirements although a few cements had difficulty meeting the restrained-expansion requi rements. The application of the proposed specification called attention to several shortcomings in the specification. Both concretes and mortars made with Type K expansive cements generally had higher compressive strengths than comparably proportioned Type II cement mixtures. Slumps of Type K cement concrete were generally less than the Type II cement control mixture. Observations of air contents in both mortar and concrete suggest that some compatibility problems between certain individual cements and air-entraining agents may exist. The data indicate that the use of Type K cements in a wide variety of different applications should pose no extraordinary problems.

DOI:

10.14359/6676


Document: 

SP64-10

Date: 

July 1, 1980

Author(s):

David 0. Lower

Publication:

Symposium Papers

Volume:

64

Abstract:

The purpose of this paper is to sumarize and report the results of field installations of Type K shrinkage-compensating concrete in bridge decks in Ohio. Typical examples concerning methods of placement, finishing, and mix designs are presented as well as the results of these procedures. Long-term results in the form of field inspections and half-cell potential readings are presented. Specifications and cost data are also included. The conclusion is drawn that the use of shrinkage-compensating concrete as a bridge deck material will reduce the instance of cracking and, consequently, reduce reinforcing steel corrosion which, in the opinion of the writer, is the major cause of bridge deck failure.

DOI:

10.14359/6677


Document: 

SP64-11

Date: 

July 1, 1980

Author(s):

D.G. Calvert

Publication:

Symposium Papers

Volume:

64

Abstract:

A serious problem in well cementing is the failure of bond between the cement and the fomation or the pipe. Such fai ure may allow fluid and/or gas movement from one zone to another. Also, a poor bond may result in loss of produced materials, premature reservoir depletion, and unsatisfactory stimulation operations. A means of decreasing such problems is the introduction of expansive properties to the cement system and has been recognized for some time. The addition of salts and other means have been used for this purpose. The availability of expansive cements opened a new area of investigation. This paper compares the expans ion properties of shr inkage-compensating cements with other cements. Other properties such as pumping time, compressive strength, and bonding of the cement systems were evaluated

DOI:

10.14359/6678


Document: 

SP64-12

Date: 

July 1, 1980

Author(s):

Mark W. Hoffman

Publication:

Symposium Papers

Volume:

64

Abstract:

All concrete structures are affected by shrinkage and creep; post-tensioning introduces elastic shortening as well. This paper compares the effect of volume changes on structures using expansive cement concrete and conventional cement concrete. The primary focus of the paper is to show that the use of expansive cement concrete can minimize the induced moments created by volume changes. A structural example is used to compare these effects. A series of concrete bars tested for the amount of expansion that occurs in restrained and unrestrained conditions is discussed. A computer program used to perform a stiffness analysis on frames using sectional properties and displacement loadings (shortening or expansion movements) is described.

DOI:

10.14359/6679


Document: 

SP64-13

Date: 

July 1, 1980

Author(s):

Frank A. Randall, Jr.

Publication:

Symposium Papers

Volume:

64

Abstract:

Reports on a field survey of over 100 projects including parking structures, slabs on ground, and miscellaneous installations that used shrinkage-compensating cement concrete. Fifty nine of the projects were rated on the effectiveness in reducing drying shrinkage cracks and it was concluded that, on average, the cement was very effective. Six years later seventeen of them were re-examined and it was found that the cement was still very effective. Cracks are plotted on several plan drawings. A number of the projects were inspected several times within a year to determine the rate and extent of cracking. Some causes of cracking due to drying shrinkage are discussed. Twelve projects of portland cement concrete were also reported.

DOI:

10.14359/6680


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