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Home > Publications > International Concrete Abstracts Portal
Showing 1-5 of 130 Abstracts search results
Document:
23-152
Date:
April 1, 2024
Author(s):
Ronald Lichtenwalner and Joseph T. Taylor
Publication:
Materials Journal
Volume:
121
Issue:
2
Abstract:
This experimental study evaluated the correlation between measured concrete expansion from a modified version of the miniature concrete prism test (MCPT) with the concentration of chemical markers leached from the prisms into an alkaline soak solution. Fifteen concrete mixture designs were tested for expansion and soak solution concentrations over time. The changes in expansion and soak solution concentrations were found to correlate well even with variations in alkali loading and substitution of cement with Class F fly ash. A model was developed to estimate the expansion potential of concrete based on an expansion reactivity index (ERI) that incorporated the concentrations of silicon, sulfate, calcium, and aluminum. The relationship between ERI and expansion was then used to identify potentially expansive concrete mixtures using the ERI of cores taken from a structure exhibiting potential alkalisilica reaction (ASR) expansion and concrete cylinders matching the mixture designs of the MCPT specimens.
DOI:
10.14359/51740374
22-405
December 1, 2023
J. F. Munoz, C. Balachandran, A. Shastry, R. Mulcahy, J. M. Robertson, and T. S. Arnold
120
6
The periodic evaluation of the alkali-silica reaction (ASR) susceptibility of aggregates is a key strategy to eliminate the risk of ASR development in transportation infrastructure. A reliable and practical accelerated ASR test is paramount to improve the frequency and efficiency of the aggregate evaluation campaign. This paper assesses the suitability of the new Turner-Fairbank Highway Research Center ASR susceptibility test (T-FAST) as a costeffective tool to evaluate aggregates. Thirty-eight aggregates of varying mineralogies, including carbonates, were characterized using the T-FAST and AASHTO T 380. The results were compared with historic AASHTO T 303 data. The T-FAST accurately classified the reactivity of the aggregates and was identified as the most sensitive among the three accelerated tests. Additionally, the combination of the T-FAST results with the possibility of accurately determining the alkali thresholds of the aggregates provided a broader understanding of the conditions conducive to triggering ASR in the field.
10.14359/51739152
21-158
July 1, 2022
Adelson Prado, Yane Coutinho, Fernanda Ferreira, Gorki Mariano, and Arnaldo Carneiro
119
4
The deterioration of concrete due to alkali-silica reaction (ASR) is a worldwide problem. Rocks close to shear and/or fault zones generally favor the occurrence of this reaction when used as aggregates in concrete. This study evaluated six coarse aggregates from quarries at different distances from shear and fault zones in the eastern part of the state of Pernambuco, Brazil, to verify the influence of tectonic deformation in the aggregate reactivity. Petrographic analyses and accelerated mortar bar tests were performed. The presence of microcrystalline quartz from dynamic recrystallization in samples collected closer to transcurrent shear zones provided higher reactivity. Therefore, a strong correlation between expansion/microcrystalline quartz content and distance from transcurrent shear zones was obtained. Thus, the geological mapping and characterization may provide an initial and fast indication of the reactive potential of aggregates, being a guidance for the choice of the extraction location or an initial indication of the need to use mitigation measures.
10.14359/51734684
21-298
May 1, 2022
Keikhosrow Tahmureszadeh, Medhat H. Shehata, and Bill Gong
3
The durability of three repair materials was investigated under two exposures: freezing-and-thawing cycles in the presence of deicing salts, and substrate undergoing expansion due to alkali-aggregate reaction (AAR). The bond strength of the repairs under freezing-and-thawing exposure was evaluated using slant shear, splitting tensile, and pulloff tests. Additionally, the pulloff test was implemented to investigate the bond strength of repairs undergoing expansion due to AAR. Under freezing and thawing, the substrate surface roughness was evaluated and resulted in a higher bond strength under combined shear and compression forces (slant shear test). The results for both exposures showed that the efficacy of a repair could not only be explained based on the net unrestrained length change between the repair and the substrate. While significant autogenous shrinkage of ultra-high-performance concrete (UHPC) can increase the net unrestrained length change, the strength, fibers, and high paste content of such material enhance the bond strength.
10.14359/51734614
21-169
March 1, 2022
K. Bharadwaj, O. B. Isgor, W. J. Weiss, K. S. T. Chopperla, A. Choudhary, G. D. Vasudevan, D. Glosser, J. H. Ideker, and D. Trejo
A new mixture proportioning method is developed for performance-based concrete with supplementary cementitious materials (SCMs). The method is based on the thermodynamic calculations of the properties for concrete and identifying the mixtures that satisfy a predefined set of performance criteria. This new approach considers the chemical composition and reactivity of SCMs while proportioning concrete mixtures. Performance criteria examples are shown for a bridge deck (corrosion and freezing-and-thawing damage), an unreinforced pavement (salt damage), and a foundation (moderate sulfate and alkali-aggregate reaction). The method is used to proportion concrete mixtures satisfying these three performance criteria using four ashes per mixture. Experiments show that these mixtures met the targets. The proposed approach can proportion mixtures that are optimized for predefined performance using a wide range of SCMs, which can be useful in reducing the cost and carbon footprint of concrete.
10.14359/51734301
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