International Concrete Abstracts Portal

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  • 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.

International Concrete Abstracts Portal

Showing 1-5 of 472 Abstracts search results

Document:

SP328-11

Author(s):

Oguzhan Bayrak

Publication:

Special Publication

Volume:

328

Issue:

  

Abstract:

Two research efforts supervised by the author of this paper and the significance of the findings of those research projects are used to facilitate the discussion to explain a couple of the challenges that the structural engineers faced in the recent past. These research programs are (i) development of the new Strut-and-Tie design provisions of AASHTO LRFD Bridge Design Specifications, and (ii) development of a new prestress loss calculation procedure.

This paper was prepared with the aim of contributing to a session organized to honor Professor Michael Collins of the University of Toronto. The discussion provided within this paper is founded on the teachings of Professor Michael P. Collins and on the experiences of the author as a graduate student. More specifically, the author of the paper had the privilege to learn from Professor Collins (i) the importance of accuracy in calibrating design provisions and (ii) the significance of reducing the design expressions down to the essential parameters. Thus, the research projects summarized in this paper serve to present examples for those important concepts and are from the personal experiences of the author.

Date:

September 12, 2018

  


Document:

SP326-72

Author(s):

Lee Brankley, Ayhan Tugrul, Ladin Camci, and Dave Knight

Publication:

Special Publication

Volume:

326

Issue:

  

Abstract:

The expectations of stakeholders across the construction industry value chain have increased significantly because of new legislation, a growing body of scientific evidence and a greater understanding of sustainability impacts. There is now a demand for companies to manage a wide range of issues in a systematic way, to improve performance and to be able to demonstrate this.

Designers and specifiers are demanding transparent, reliable data and comparable sustainability information about competing construction materials. Standard setting organizations and building rating systems are maturing in their requirements. Third-party certification bodies have responded with improved certification schemes that facilitate the provision of data collection, auditing and reporting. The CARES Sustainable Constructional Steel (SCS) scheme, which certifies reinforcing carbon and stainless steel, structural steel and hot rolled flat steel internationally, is a good example of such a scheme.

Developed with the inputs of a wide range of stakeholders, the accredited scheme is based on the foundations of technical specifications, traceability and product quality as well as the sustainability principles of inclusivity, integrity, stewardship and transparency. Specification of certified steels for reinforced concrete helps reduce detrimental and increase positive sustainability impacts across the construction industry value chain.

Date:

August 10, 2018

  


Document:

SP326-52

Author(s):

Edgardo Becker, Patricio Corallo, Juan Domínguez, Cristian Ríos, Ismael Gea, and Javier Cañari

Publication:

Special Publication

Volume:

326

Issue:

  

Abstract:

The first aim of this paper is to design concretes with minimum paste and cement contents, having strengths and workability comparable to conventional concretes. On one hand, an extensive work on packing of many available types of aggregates, with different shapes and particle size distributions, has been done to find out combinations that lead to minimum paste contents. As for the concrete, composition of paste was adjusted in order minimize cement and paste content for a given workability, a specified compressive strength and a certain aggregate combination. The second aim of this paper is to prove that, despite not complying with the minimum cement content indicated in construction codes, durability performance of those special concretes is better or, at least not worse than for conventional concretes with similar workability and compressive strength, showing that durability specifications should limit the maximum paste content, instead of the minimum cement content.

Date:

August 10, 2018

  


Document:

SP326-121

Author(s):

Satoshi Fujimoto

Publication:

Special Publication

Volume:

326

Issue:

  

Abstract:

The quality of hardened concrete is severely degraded if the concrete is frozen at its setting or hardening stage. To prevent the degradation of materials, heating of the materials, equipment and facilities is widely utilized in ready-mixed concrete plants in cold regions of Japan. The heating is widely mentioned and conditionally recommended in specifications and recommendations. While these documents refer to material types to be heated and maximum temperature that will affect the quality of concrete, they do not refer to the energy sources or heating method for equipment and facilities. These factors, however, do have influences on the environmental performances at production stage of concrete. The difference in energy sources, types of heating and operation design of heating make significant difference in the emission of carbon dioxide and other global warming substances. Considering these importance, this paper surveys the types of energy sources and its system for concrete production at ready-mixed concrete plants in cold regions of Japan. The comparison of plants by the difference in seasonal temperature and the location is analyzed through monthly use of energy and on-site observation in various plants.

Date:

August 10, 2018

  


Document:

SP326-04

Author(s):

R. Doug Hooton

Publication:

Special Publication

Volume:

326

Issue:

  

Abstract:

Many performance-based test methods adopted in various national and international standards were adopted decades ago based on short-term evaluations. Many of the durability tests use various methods of acceleration to obtain results in a reasonably short period of time, and then pass/fail criteria are set for these tests and included in standard specifications. If long-term tests conducted in the field, or at least in outdoor exposure, can verify the appropriateness of both the test methods and the test limits, then it provides confidence that the test methods are meaningful and that the specification limits are appropriate. This has been done in the case of ASTM and CSA test methods for sulfate resistance, mitigation of alkali-silica reaction, for de-icer salt scaling resistance and for resistance to chloride ingress for marine and deicer exposures. The potential downside can be that the materials and mix designs used in the long-term tests may no longer be representative of those currently in use. In addition, the precision of all test methods needs to be evaluated in inter-laboratory test programs to provide confidence in the test results obtained. This contribution describes results from several long-term test programs and inter-laboratory studies focused on verifying specific standard test methods for durability.

Date:

August 10, 2018

  


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