International Concrete Abstracts Portal

Showing 1-5 of 174 Abstracts search results

Document: 

24-096

Date: 

March 24, 2025

Author(s):

Mouhcine Ben Aicha, Ayoub Aziz, Olivier Jalbaud, and Yves Burtschell

Publication:

Materials Journal

Abstract:

This study investigates the impact of air-entraining admixtures (AEA) on mortar performance, focusing on fresh-state and hardened-state properties critical to durability and engineering applications. Ten distinct mortar mixtures were analyzed, following guidelines established by EFNARC (European Federation of National Associations Representing Producers and Applicators of Specialist Building Products for Concrete). AEAs were introduced at varying proportions (0.01–0.5% of cement weight) to evaluate their effects on intrinsic properties (density, void ratio, water absorption), rheological parameters (plastic viscosity, yield stress), and mechanical characteristics (compressive strength, ultrasonic velocity, modulus of elasticity).

Regression models were developed, yielding high predictive accuracy with R² values exceeding 0.98. Notably, ultrasonic velocity and modulus of elasticity demonstrated strong correlations with intrinsic properties across all curing ages. Similarly, compressive strength showed significant associations with rheological parameters, highlighting the influence of air content and flow behavior on structural performance. These findings offer precise quantitative models for predicting mortar behavior and optimizing formulations for enhanced performance.

DOI:

10.14359/51746715


Document: 

22-298

Date: 

September 1, 2024

Author(s):

Junhyung Kim and Raissa Douglas Ferron

Publication:

Materials Journal

Volume:

121

Issue:

5

Abstract:

Embedding magnetic particles into cement paste produces a smart material in which the rheological properties of the resultant paste can be actively controlled through the use of magnetorheological (MR) principles. This research investigates the rheological behavior of cement-based MR pastes with and without air entrainment to gain a better understanding of the effects of air-entrained bubbles on MR cement pastes. Such information would be critical for the use of such MR pastes in three-dimensional (3-D) concrete printing applications. It is revealed that the incorporation of entrained air increases the MR response, and this effect is related to the bubble-bridge effect.

DOI:

10.14359/51742113


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: 

19-488

Date: 

November 1, 2020

Author(s):

Emmanuel K. Attiogbe

Publication:

Materials Journal

Volume:

117

Issue:

6

Abstract:

A mechanistic analysis is presented on the characteristics that would enable particles that form annulus voids when concrete freezes to be used as an alternative technology to air entrainment for protection of concrete from freezing-and-thawing damage. The paper introduces a concept of particle compliance and related equations to establish a fundamental basis for identifying and selecting particle types to use as additives in concrete to prevent freezing-and-thawing damage. Standard freezing-and-thawing testing confirms the results of the analysis and shows that the minimum quantity of particles needed to achieve a freezing-and-thawing durable concrete varies with the particle type. Particle types such as polymeric hollow-core microspheres or polymeric solid-core particles would be insensitive to the factors that impact air entrainment obtained with surfactants, resulting in a more robust and reliable basis to consistently protect concrete from freezing-and-thawing damage.

DOI:

10.14359/51726995


Document: 

18-484

Date: 

November 1, 2019

Author(s):

M. Khanzadeh Moradllo, C. Qiao, M. Keys, H. Hall, M. T. Ley, S. Reese, and W. J. Weiss

Publication:

Materials Journal

Volume:

116

Issue:

6

Abstract:

The absorption of fluid in concrete is often useful in the prediction of durability. Studies on the influence of entrained air voids (air content and quality) on fluid absorption in concrete are unfortunately very limited. This paper investigates fluid (water) absorption in air-entrained concrete mixtures with three water-cement ratios (w/c = 0.40, 0.45, and 0.50) and a range of air contents (2.5 to 9.0%) with and without high-range water reducer. Neutron radiography is used to measure the time-dependent depth of water penetration, water absorption, and the degree of saturation. In addition, water absorption is related to the apparent formation factor, which is determined from electrical resistivity measurements on concrete samples immersed in a simulated pore solution. Results show that air content has a minimal impact on the rate of water absorption of the matrix. However, the air content significantly alters the degree of saturation, with higher air contents having a lower degree of saturation. As the w/c decreases, the rate of water absorption is reduced due to the refined microstructure. For the given w/c, the addition of the high-range water reducer has a slight reduction in the rate of water absorption. Results indicate a linear relationship between sorptivity (initial and secondary) and the reciprocal of the square root of the apparent formation factor. This relationship can provide a powerful tool in quality control to obtain the apparent formation factor.

DOI:

10.14359/51716980


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