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Home > Publications > 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 57 Abstracts search results
Document:
23-007
Date:
September 1, 2024
Author(s):
R. A. Livingston, P. Sridhar, N. S. Berke, A. M. Amde, and H. H. Chen-Mayer
Publication:
Materials Journal
Volume:
121
Issue:
5
Abstract:
Prompt-gamma activation analysis (PGAA) is an elemental analysis method based on radiative neutron capture that has a high sensitivity to chlorine (Cl). To evaluate the feasibility of replacing the conventional wet chemistry method, ASTM C1152, with PGAA, four mixtures of concrete were prepared with Cl added, ranging from a 0.004 to 0.067% mass fraction of Cl in concrete. The PGAA method detected levels of 100 μg/g Cl in concrete. While both the PGAA and C1152 methods gave results systematically below the nominal values of added Cl, the PGAA data showed excellent correlation (R2 of 0.999) with the C1152 results measured on the same samples. Given that PGAA can measure Cl in concrete as well as C1152 and is faster and less labor-intensive, it can be a candidate for development as a standard method for an alternative to the latter.
DOI:
10.14359/51742035
22-164
April 1, 2024
Avinaya Tripathi, Sooraj A. O. Nair, Harshitsinh Chauhan, and Narayanan Neithalath
2
Conventional approaches to concrete three-dimensional (3-D) printing relies on printing concrete in a straight (linear) print path, with layers overlaid on top of each other. This results in interlayer and interfilament joints being potential weak spots that compromise the mechanical performance. This paper evaluates simple alterations to the print geometry to mitigate some of these effects. A printable mixture with 30% of limestone powder replacing cement (by mass), with a 28-day compressive strength of approximately 70 MPa in the strongest direction is used. S- and 3-shaped print paths are evaluated as alternatives to the linear print path. Staggering of the layers ensures that the interfilament joints do not lie on the same plane along the depth. Flexural strength enhancement is observed when print geometries are changed and/or layers are staggered. The study shows that print geometry modifications mitigate mechanical property reductions attributed to interfilament defects in 3-D concrete printing.
10.14359/51740262
21-100
May 1, 2023
Keun-Hyeok Yang, Ju-Hyun Mun, Seung-Jun Kwon, and Jong-Won Kim
120
3
The atmospheric purification capacity of concrete has not beenadequately investigated. This study examines the feasibility ofusing sustainable foam-concrete granules as a porous materialfor reducing air pollutants in concrete. To enable the removal of nitrogen oxide (NOx) and sulfur oxide (SOx) using titanium dioxide (TiO2) nanoparticles, foam concrete was crushed into granules with porosity exceeding 30%. Ordinary portland cement (OPC), fly ash (FA), and slag cement were used as source cementitious materials. OPC was replaced with 0 to 40% FA and 0 or 40% slag cement by weight. Test results indicate that 30% FA and unit cementitious materials content exceeding 500 kg/m3 (31.2 lb/ft3) are optimal for replacing cement and foam-concrete granules, respectively. Considering the particle-size distribution and specific surface area, 6 to 13 mm (0.24 to 0.51 in.) and 6 to 9 mm (0.24 to 0.35 in.), were selected as optimal granule sizes. The coating procedures yielded improved SOx and NOx removal, with the removal rates reaching 83.8 and 45% using granules of 6 to 9 mm (0.24 to 0.35 in.), respectively. Consequently, the foam-concrete granules coated with TiO2 nanoparticles are promising in developing porous concrete with the reduction capability of air pollutants.
10.14359/51738507
21-497
November 1, 2022
Rita E. Lederle and Amanda Birnbaum
119
6
This study tested the effect of using taconite as an aggregate replacement in concrete. Taconite is a by-product from iron ore mining that has the potential to be used in concrete production as a coarse and/or fine aggregate. Replacing the aggregate in a concrete pavement with taconite could decrease the demand for increasingly scarce high-quality aggregates. The mechanical properties of concrete made with only fine, only coarse, or both fine and coarse taconite aggregates were tested. Properties tested include compressive, flexural, and tensile strength; elastic modulus; and coefficient of thermal expansion. All concretes made with taconite coarse and fine aggregate, either alone or in combination, produced concrete with acceptable mechanical properties for use in paving. The use of taconite coarse aggregate increased all mechanical properties tested, while the use of taconite fine aggregate had mixed effects on mechanical properties, but values of all properties tested remained within normal ranges. Fresh concrete properties were also tested, and taconite was found to decrease workability. This work shows that both coarse and fine taconite aggregates have the potential to be used as viable aggregates for concrete.
10.14359/51736003
20-398
January 1, 2022
G. P. Cordoba, A. Rossetti, S. V. Zito, V. F. Rahhal, D. Falcone, and E. F. Irassar
1
The use of calcined clays in cement (kaolinitic and common calcined clays) introduces challenges due to the high alumina content, large specific surface area, and high-alkali content. This paper examines the performance against sulfate attacks, alkali-silica reactions, and chloride penetration in mixtures with calcined illitic shale (CIS). Replacement of high and moderate alkali content cement with 25% CIS significantly reduces the expansion in the alkali-silica reaction (ASR) test, as the pozzolanic reaction contributes to the combination of alkalis. Replacing 20% white portland cement with CIS allows the formulation of sulfate-resistant cement by limiting the formation of gypsum and ettringite. The incorporation of 25% CIS in concrete does not significantly increase chloride ingress. Therefore, blended cements with replacement levels of 20 to 25% of portland cement by CIS reduce or maintain the performance against ASR, sulfate attack, and chloride penetration.
10.14359/51734192
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