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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 357 Abstracts search results

Document: 

21-470

Date: 

November 2, 2022

Author(s):

Julie K. Buffenbarger, James M. Casilio, Hessam AzariJafari, and Stephen S. Szoke

Publication:

Materials Journal

Abstract:

The overdesign of concrete mixtures and substandard concrete acceptance testing practices significantly impact the concrete industry's role in sustainable construction. This study evaluates the impact of overdesign on the sustainability of concrete and embodied carbon emissions at the national and project scales. In addition, this paper reviews quality results from a concrete producer survey; established industry standards and their role in acceptance testing in the building codes; the reliance on proper acceptance testing by the Licensed Design Professional, Building Code Official, and the project owner; and the carbon footprints that result from overdesign of concrete mixtures. In 2020, a field survey conducted on over 100 projects documented Pennsylvania's quality of field testing. Of those surveyed, only 15% percent of the projects met the testing criteria within the ASTM and building code requirements. As a result, the total overdesign-induced cement consumption is as large as 6.7% of the U.S. estimated cement used in the U.S.

DOI:

10.14359/51737334


Document: 

22-074

Date: 

November 1, 2022

Author(s):

Yubo Sun, Yaxin Tao, A. V. Rahul, Guang Ye, and Geert De Schutter

Publication:

Materials Journal

Volume:

119

Issue:

6

Abstract:

The rapid workability loss of alkali-activated materials (AAMs) has been a major obstacle limiting their on-site application. In this study, two conventional high-range water-reducing admixtures (HRWRAs) (made of polynaphthalene sulfonate [PNS] and lignosulfonate [LS] salts), which have been reported to be effective in some specific AAM mixtures, were separately applied in alkali-activated slag (AAS) concretes. A comprehensive testing program was performed to study their effect on reaction kinetics, rheology evolution, and strength development. Results showed that sodium silicate-activated AAS mixtures exhibited lower yield stress than those activated by sodium hydroxide. In hydroxide media, PNS and LS remained effective in reducing yield stress and increasing slump value, while they both failed to improve the rheological behavior of AAS activated by silicate. Moreover, the inclusion of 2% admixtures did not result in much strength reduction in either activator, although LS showed a retardation effect and subsequent increase in the setting time in the fresh state.

DOI:

10.14359/51737192


Document: 

21-392

Date: 

November 1, 2022

Author(s):

Arjun Siva Rathan R. T., Sunitha V., and Anusudha V.

Publication:

Materials Journal

Volume:

119

Issue:

6

Abstract:

Interlocking concrete block pavement (ICBP) is one of the pavement types adopted worldwide. The influential parameter of ICBP is comparatively more, which includes the geometric parameters of the interlocking paver blocks such as the size, shape, thickness, strength, and laying pattern of the blocks, and the gradations of the jointing and bedding sand. Other than the wearing surface, the thickness and properties of the bedding sand, base, and subgrade also play a vital role in the deflection properties of ICBP. The objective of the present study is to analyze the influence of block thickness, base thickness, and granular layer thickness on the deflection behavior and stress distribution of ICBP. The block thicknesses used for this study are 80, 100, and 120 mm; the bedding sand thicknesses are 30, 50, and 70 mm; and the base thicknesses are 150, 300, and 450 mm. The experimental work is carried out using the laboratory plate load test to determine the deflection and stress distribution of ICBP. Numerical analysis is also employed to simulate laboratory testing. The study attempts to find the most influential factor and the optimized parametric value for attaining lower deflection using Design-Expert software. The test results conclude that the thicknesses of the block and granular layer play an imperative role among the considered parameters.

DOI:

10.14359/51736002


Document: 

22-064

Date: 

November 1, 2022

Author(s):

Julia A. Bruce, Evan C. Bentz, and Oh-Sung Kwon

Publication:

Materials Journal

Volume:

119

Issue:

6

Abstract:

This paper summarizes the results of a pilot experimental program intended to develop a robust data for global airflow through cracked concrete, with comparisons against a traditionally used prediction method. Current models for predicting airflow through concrete based on Poiseuille flow poorly translate to large-scale specimens and real-world conditions without calibration. This paper presents a novel testing apparatus that will be used to identify key variables affecting flow rate and develop numerical prediction methods for industrial application.

DOI:

10.14359/51737197


Document: 

22-023

Date: 

November 1, 2022

Author(s):

Saman Hedjazi and Ehsanul Kabir

Publication:

Materials Journal

Volume:

119

Issue:

6

Abstract:

Chloride diffusivity and steel corrosion are two major factors in the durability characteristics of concrete structures. It is possible to use the electrical resistivity (ER) of concrete as a measure of concrete’s ability to resist the movement of ions within the material. In this study, surface electrical resistivity (SR) and bulk electrical resistivity (BR) of concrete cylinders were measured from 3 to 161 days for concrete mixtures with four varying water-cement ratios (w/c) (0.45 to 0.60) and three distinct cement types. The study investigated the influence of important durability parameters such as cement type, long-term curing period, and w/c on concrete electrical resistivity. In addition, the impact of cylinder size on SR of concrete was observed. The findings show that both SR and BR of concrete decrease with increasing w/c, except for concrete with cement Type-I/II, which showed a minor increase in resistivity with a w/c of 0.55. Concrete with Type-V cement showed the highest electrical resistance. Moreover, a strong linear relationship between the two types of resistivity was established, and a new equation was introduced in terms of cement type, w/c, and long-term curing period. The correlation between SR and BR was validated by determining the mean absolute error (MAE) of the proposed equation for the three types of cement, which were 0.41 (Type-I/II), 0.65 (Type-III), and 0.35 (Type-V). For all three cement types, the mean absolute percentage error (MAPE) and coefficient of variation (COV) were within acceptable limits, and the 95% confidence interval (CI) indicated a small error margin for the proposed equation when estimating BR from SR using experimental data. Statistical analysis showed that the new equation was less reliable for Type-III cement than the other two types, possibly due to its rapid strength increase property.

DOI:

10.14359/51737191


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