International Concrete Abstracts Portal

International Concrete Abstracts Portal

The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

Showing 1-5 of 13 Abstracts search results

Document: 

SP136-06

Date: 

January 1, 1993

Author(s):

Mark D. Luther

Publication:

Symposium Papers

Volume:

136

Abstract:

Structural Lightweight Aggregate Concrete

DOI:

10.14359/4265


Document: 

SP136-07

Date: 

January 1, 1993

Author(s):

Alexander M. Vayasburd

Publication:

Symposium Papers

Volume:

136

Abstract:

During the past three decades, lightweight aggregate concrete has emerged as an important sector of the structural concrete industry. It possesses unique properties, similar in some ways to those of normal weight concrete, but differing in significant aspects. Difficulties experienced with lightweight concrete in some projects appears to be caused by a lack of understanding of the differences between normal weight concrete and lightweight concrete as materials and differences in production technologies. It is most wisely used when treated as a material in its own right, with its special properties fully considered in design and construction. A three-phase model of lightweight concrete and its effect on durability are discussed as they relate to selection of materials, concreting and curing technology, control of in-service distress due to freezing and thawing, and corrosion of reinforcing steel. ased on the observed performance of bridge and marine structures built over the past four decades, the author presents a series of generalized observations applying to durability of lightweight concrete that provide a fair cross section of the entire experience. Paper concludes that, with proper selection of materials and design, and good construction practices, lightweight concrete offers an excellent solution to the problem of durability in severe environment.

DOI:

10.14359/4267


Document: 

SP136-09

Date: 

January 1, 1993

Author(s):

T. W. Bremner, T. A. Holm, and J. M. McInerney

Publication:

Symposium Papers

Volume:

136

Abstract:

The effect of stress on the nitrogen gas permeability of structural lightweight concrete was determined using cylindrical hollow concrete specimens loaded in axial compression at the same time that a nitrogen pressure differential was maintained across the cylinder wall. The nitrogen gas flow rate across the cylinder wall was noted and concrete permeability was measuredas the load increased. Flow rates tended to remain constant up to a critical stress corresponding to the onset of unstable crack propagation, at which time the flow rate increased rapidly. Rapid increases in permeability occurred at lower levels of applied stress-to-strength ratio with normal weight concrete than with lightweight concrete.

DOI:

10.14359/4269


Document: 

SP136-04

Date: 

January 1, 1993

Author(s):

Russell Trumble and Luis Santizo

Publication:

Symposium Papers

Volume:

136

Abstract:

Project consists of a 15-story office tower and a 4-level parking structure. The advantages of lightweight concrete over other structural materials for this particular project, and the process followed for its selections, as well as different types of structural systems, are evaluated. The length of spans in both structures was a determining factor in the selection of the floor system. Lightweight concrete, 4000 psi, was chosen for the floors, and 6000-psi normal weight concrete was selected for the columns. As a first step of the design process, economic comparisons were made between concrete and structural steel. After determining that concrete was more economical, alternate floor systems were studied for constructability, function, economy, and availability of materials. Lightweight concrete was preferable for all floor systems, even though a premium cost of nearly 10 dollars per yd 3 is common for this geographic location.

DOI:

10.14359/4202


Document: 

SP136-05

Date: 

January 1, 1993

Author(s):

James E. Roberts

Publication:

Symposium Papers

Volume:

136

Abstract:

Describes the use of expanded shale lightweight concrete for both older bridge widenings and new bridge construction on the California State Highway System in the past 30 years. Examples of major projects illustrate the durability and reliability of a properly designed and constructed lightweight aggregate bridge. Cost comparisons of lightweight aggregate structures bid in competition with structural steel and normal weight concrete alternative structures highlight the economic viability of this material. The outstanding performance of these lightweight bridges under heavy traffic and the close competition in bidding suggests that lightweight aggregate is a material that should be considered in future bridge designs, especially in earthquake country, where dead load is such an important factor in seismic design. The known consistent creep, shrinkage, and modulus properties of lightweight aggregate remove any doubts about performance, as certain structures have demonstrated. Industry advances in controlling moisture content have reduced considerably the handling and finishing problems of earlier years.

DOI:

10.14359/4240


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