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 1-10 of 94 Abstracts search results

Document: 

SP-332_02

Date: 

July 1, 2019

Author(s):

Pericles C. Stivaros

Publication:

Special Publication

Volume:

332

Abstract:

A successful concrete repair project requires a close coordination of efforts between the three major parties involved: the owner, the licensed design professional (LDP), and the contractor. Lack of coordination and clear understanding of the professional and contractual responsibilities, as well as the expectations, of each party involved in a concrete repair project, could result in long legal disputes to attempt to sort out the responsibilities of each party. The greatest victim of the dispute is usually the structure itself. The American Concrete Institute (ACI) has led the effort to develop responsibility guidelines in concrete construction. ACI 132 identifies and suggests the allocation of responsibilities to various parties involved in concrete construction. ACI 132 document is applicable to general concrete construction, and it does not consider the particularities of evaluating and repairing existing concrete structures. ACI 562 provides minimum requirements for assessment, repair and rehabilitation of existing distressed concrete structures, including a discussion on the responsibilities of the licensed design professional for the evaluation and repair of concrete structures. This paper discusses the responsibilities of the licensed design professional, the contractor, and the owner through a repair case study. The paper demonstrates the need to expand ACI 132 and/or ACI 562 to include responsibility guidelines for concrete repair projects.


Document: 

CI3909Kaufman

Date: 

September 1, 2017

Author(s):

Alfred L. Kaufman Jr. and Michael J. Morrison

Publication:

Concrete International

Volume:

39

Issue:

9

Abstract:

ACI is offering a new certification program—Concrete Quality Technical Manager (CQTM). The CQTM program is intended to identify and confirm individuals who possess the knowledge and experience necessary to supervise an effective concrete quality assurance/quality control program, manage those duties on behalf of a ready mixed concrete company, or represent the design professional in technical matters pertaining to the concrete used on a project.


Document: 

CI3908Q&A

Date: 

August 1, 2017

Publication:

Concrete International

Volume:

39

Issue:

8

Abstract:

I’m a technician with a testing laboratory. On one of my projects, I understand that the specified strength is 10,000 psi (68.9 MPa), based on compressive tests of field-cured cylinders. For quality assurance, we are also testing standard-cured cylinders. The field-cured cylinders are consistently breaking at strengths that are 25 to 35% lower than the standard-cured specimens. Why such a difference in strength?


Document: 

CI3708Kane

Date: 

August 1, 2015

Author(s):

Kevin Kane, Todd Laker, and Steve Morrical

Publication:

Concrete International

Volume:

37

Issue:

8

Abstract:

There is a concern among ready mixed concrete producers that quality assurance testing is not consistently performed in accordance with ASTM standards. All project participants are affected by substandard testing practices, as false-positive or false-negative test results can lead to rejections of good concrete loads or acceptance of bad quality concrete, respectively. The article makes recommendations for evaluating and improving the quality of concrete testing, and it describes a program that allows testing agencies and their technicians to assess their performance relative to their peers.


Document: 

SP303-18

Date: 

June 1, 2015

Author(s):

Frank Shaode Ong, Charles K. Nmai, James Curtis Smith, and John Luciano

Publication:

Special Publication

Volume:

303

Abstract:

The focus of this paper is a new liquid microspheres-based admixture that has been developed to provide freezing and thawing protection of cementitious-based materials under cyclic, saturated conditions, while addressing and eliminating issues typically associated with the use of surfactant-based admixtures for air entrainment. Consequently, this microspheres-based admixture provides unique opportunities and flexibility in reproportioning or optimizing current air-entrained concrete mixtures with respect to using increased levels of supplementary cementitious materials. It is also shown in the paper that the microspheres-based admixture will facilitate the use of materials that typically hinder air entrainment. A microspheres recovery test method that has been developed to measure the microspheres content of fresh content for quality assurance purposes is also presented and discussed.


Document: 

CI3701Snell2

Date: 

January 1, 2015

Author(s):

Luke M. Snell

Publication:

Concrete International

Volume:

37

Issue:

1

Abstract:

Handheld infrared (IR) thermometers have been found to work well in the relatively narrow temperature range commonly seen in concrete construction: 0 to 120°F (-20 to -45°C). Although IR thermometers are not sufficiently accurate for some quality assurance tests, they do make it possible to estimate concrete temperatures and evaluate casting surface temperatures without interfering with the concrete placements. The article provides user guidance and lists possible applications for IR thermometers in concrete construction.


Document: 

CI3605Nadelman

Date: 

May 1, 2014

Author(s):

Elizabeth I. Nadelman and Kimberly E. Kurtis

Publication:

Concrete International

Volume:

36

Issue:

5

Abstract:

Several state and federal agencies have shown interest in adopting surface resistivity (SR) measurement for quality assurance testing. But SR measurement may also be used for assessing and predicting the long-term performance of concrete mixtures during the mixture design stage. As shown in this article, the SR test demonstrates the influence of binder composition on the rate of microstructural development in concrete and can therefore provide a means for assessing future performance.


Document: 

CI3209Taber

Date: 

September 1, 2010

Author(s):

Lawerence Taber

Publication:

Concrete International

Volume:

32

Issue:

9

Abstract:

This article is an introduction to a series of articles based on a technical session sponsored by ACI Committee E702, Designing Concrete Structures. This series is intended to build on that session. While the target audience is primarily young engineers in professional practice, the series will also be of use to more experienced engineers as a basic review. Numerous types of reports cross the desk or the computer screen of the practicing engineer on a daily basis. Reports can help engineers design correctly, monitor the progress and quality of construction, resolve construction problems, and provide a concise written record of events. The benefits gained from a report are limited by its quality and timing, so it is important to know what to request and when to ask for it.


Document: 

CI3209Gjorv

Date: 

September 1, 2010

Author(s):

Odd E. Gjørv

Publication:

Concrete International

Volume:

32

Issue:

9

Abstract:

The durability of concrete structures is related not only to design and materials but also to construction. Construction quality is highly variable, and in severe environments any deficiencies will soon be revealed. To a certain extent, a probability approach to the durability design can take the high variability into account. For concrete structures in severe environments, construction quality and variability are key to any rational approach to more controlled durability. Performance-based concrete quality assurance during construction, along with proper documentation, is essential. Examples of recent applications are summarized.


Document: 

CI3203Kevern

Date: 

March 1, 2010

Author(s):

John Kevern and Jereme Montgomery

Publication:

Concrete International

Volume:

32

Issue:

3

Abstract:

Pervious concrete mixtures are generally proportioned to have 15 to 25% air void contents to ensure adequate infiltration rates and strength. New ASTM standards for determining density and void content as well as infiltration rate were recently used as part of the quality assurance program for the construction of a parking lot in Omaha, NE. Test placements were used to develop a compaction-density relationship for test samples, and this was correlated to the void contents of pavement samples. Workability tests and unit weight tests were used to screen loads to ensure that concrete was workable and could be consolidated to achieve a target air void content. Test cores taken after the pavement hardened showed that the quality assurance testing program was successful.


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