ABOUT THE 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.

International Concrete Abstracts Portal

Showing 1-5 of 372 Abstracts search results

Document: 

23-334

Date: 

September 13, 2024

Author(s):

Christopher Wilkes, Fragkoulis Kanavaris, Chris Barker, Duncan Nicholson

Publication:

Materials Journal

Abstract:

This paper presents a method for simply qualifying the practical risk of casting deep foundations based upon a combination of the behavior of the fresh concrete through testing and the confinement conditions of the foundation from a design perspective. A framework to qualify which aspects of the tremie process lead to defects is developed for the first time. Flow behavior, confinement conditions, and free-water availability are identified as key contributors to specific defects present within tremie concrete foundations. Finally, a novel risk map for tremie concrete is presented.

DOI:

10.14359/51742262


Document: 

23-256

Date: 

September 13, 2024

Author(s):

David C. Burney, Kimberly E. Kurtis, Laurence J. Jacobs, and Ryan J. Sherman

Publication:

Materials Journal

Abstract:

Despite improvements in nondestructive testing (NDT) technologies, the quality assurance of concrete reinforcing bar (rebar) placement is still primarily conducted with conventional methodologies, which can be time-consuming, ineffective, and damaging to the concrete components. This study investigated the performance of two commercially available cover meters and one ground penetrating radar (GPR) device. A cover meter was found to have the greatest accuracy for depths smaller than 3.19 in. (81.0 mm), while the GPR performed better for greater depths. The effect of reinforcing bar depth, diameter, and type; neighboring reinforcing bar; and concrete conditioning on the performance of the devices was quantified. The use of epoxy-coated reinforcing bar, galvanized reinforcing bar, and stainless-steel reinforcing bar was found to have a negligible effect on cover meter accuracy. A model was developed to predict the precision of the GPR post-measurement analysis given a depth and concrete dielectric constant.

DOI:

10.14359/51742260


Document: 

22-400

Date: 

August 1, 2024

Author(s):

Justin Becker, M. Tyler Ley, and Daniel Cook

Publication:

Materials Journal

Volume:

121

Issue:

4

Abstract:

Pumping of air-entrained concrete can result in variable air content, which leads to possibly rejected concrete. This research used air volume, super air meter (SAM) number (AASHTO T 395), bulk freezing and thawing (ASTM C666/C666M), and hardened air-void analysis (ASTM C457/C457M) to investigate the air-void quality and freezing-and-thawing durability performance of concrete before and after pumping. The laboratory results show that the fresh-air testing measurements after pumping fresh concrete are not accurate indicators of the freezing-and-thawing resistance based on the hardened air-void analysis. However, testing fresh concrete prior to pumping is a better indicator of the freezing-and-thawing performance.

DOI:

10.14359/51740774


Document: 

23-093

Date: 

May 1, 2024

Author(s):

Liang Li

Publication:

Materials Journal

Volume:

121

Issue:

3

Abstract:

Time-zero is of considerable significance for determining both deformational and mechanical properties of high-performance concrete from very early ages. In this paper, four methods for determining the time-zero are investigated comparably, including stress evolution measurement, autogenous strain method, ultrasonic testing, and temperature rate method. A critical review of the theoretical basis behind each method is presented, with emphasis on the applicability and limitations of each method. Based on a case study, the practical capabilities of all four methods for determining the time-zero of high-performance concrete with a waterbinder ratio (w/b) of 0.25 are experimentally assessed. It is found that the ultrasonic testing and temperature rate methods are better suited due to their simplicity and availability compared to the other two methods. Besides, the temperature of cement-based composites at very early ages can affect the determined values of time-zero, which needs further research.

DOI:

10.14359/51740565


Document: 

23-055

Date: 

May 1, 2024

Author(s):

Sangyoung Han, Thanachart Subgranon, Hung-Wen Chung, Kukjoo Kim, and Mang Tia

Publication:

Materials Journal

Volume:

121

Issue:

3

Abstract:

A comprehensive laboratory testing program, field-testing program, numerical analysis, and life-cycle cost analysis were conducted to evaluate the beneficial effects of incorporating shrinkage-reducing admixture (SRA), polymeric microfibers (PMFs), and optimized aggregate gradation (OAG) into internally cured concrete (ICC) mixtures for rigid pavement applications. Results from the laboratory program indicate that all the ICC mixtures outperformed the standard concrete (SC) mixture. All the ICC mixtures showed a decrease in drying shrinkage compared to the SC mixture. Based on the laboratory program, three ICC mixtures and one SC mixture were selected for the full-scale test and subjected to a heavy vehicle simulator for accelerated fatigue testing. Extensive testing and analysis have shown that ICC mixtures incorporating SRA, PMFs, and OAG can be beneficially used in pavement applications to achieve increased pavement life.

DOI:

10.14359/51740564


12345...>>

Results Per Page