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International Concrete Abstracts Portal

Showing 1-5 of 57 Abstracts search results

Document: 

20-188

Date: 

March 1, 2021

Author(s):

Noura Sinno, Matthew Piersanti, and Medhat H. Shehata

Publication:

Materials Journal

Volume:

118

Issue:

2

Abstract:

This paper presents tests that can be used collectively to provide a qualitative assessment of residual expansion in structures affected by alkali-silica reaction (ASR). The tests are applied to bridge barriers suffering different levels of ASR deterioration. These include testing extracted cores under different lab conditions, monitoring concrete elements under field condition, damage rating index (DRI) on cores, and measuring alkali levels in the affected concrete. Expansion of barriers with low deterioration level was double that of highly deteriorated barriers at 4.5 years. Similar results were reached through testing cores under laboratory conditions at 38°C (100°F) and 100% relative humidity, although the DRI showed the same increase in damage in both cores after testing. Testing cores under laboratory conditions until expansion ceases helps in predicting the minimum residual expansion. Soaking cores in alkaline solutions of different concentrations and finding the level required to trigger expansion helps in assessing the risk of future expansion.

DOI:

10.14359/51729330


Document: 

20-049

Date: 

January 1, 2021

Author(s):

J. Abellán-García, J. A. Fernández-Gómez, N. Torres-Castellanos, and A. M. Núñez-López

Publication:

Materials Journal

Volume:

118

Issue:

1

Abstract:

This paper investigates the tensile behavior of green ultra-high-performance fiber-reinforced concrete (UHPFRC) using commercially available steel fibers. An ecofriendly ultra-high-performance concrete (UHPC) with a low carbon footprint was developed, aiming for a compressive strength of 150 MPa (22 ksi) and a high packing density (0.81) while using recycled glass powder and micro-limestone powder as partial substitution of silica fume and ordinary portland cement. Besides the commercially available normal-strength deformed steel fibers, high-strength smooth steel fibers were used to establish a comparison. The study showed that, with appropriate hooked normal-strength and smooth high-strength steel fibers, 1% of fiber is enough to achieve strain hardening behavior. Moreover, the smooth fibers achieved the maximum tensile strength (σpc = 11.04 MPa) when 2% of volume was used. However, despite having less tensile strength, only the hooked-end fibers achieved a maximum post-cracking strain (εpc) of over 0.3% using 2% of volume.

DOI:

10.14359/51725992


Document: 

19-385

Date: 

September 1, 2020

Author(s):

Tan Li and Jianzhuang Xiao

Publication:

Materials Journal

Volume:

117

Issue:

5

Abstract:

The uniaxial compression behavior of concrete with 0.98 to 3.15 in. (25 to 80 mm) large-size recycled coarse aggregate (LRCA) was numerically studied. Most of the errors between results of experimental and numerical simulation are within 5 to 10%. The finite element method was used to compare with the discrete element method (DEM). The results show that with a higher replacement rate of LRCA, the DEM has higher accuracy. Failure image of models shows that when the strength of LRCA is lower, the influence of LRCA content is more obvious to cracking patterns of concrete. Kinetic curves show that the cracking resistance of concrete with LRCA is lower than normal concrete and the logarithm of the box-counting dimension has a good linear relationship with the replacement of LRCA, which shows that cracks in the concrete with LRCA have obvious fractal features.

DOI:

10.14359/51725976


Document: 

19-253

Date: 

May 1, 2020

Author(s):

K. Tamanna, M. Tiznobaik, N. Banthia, and M. Shahria Alam

Publication:

Materials Journal

Volume:

117

Issue:

3

Abstract:

Using recycled scrap tire and construction and demolition waste as aggregates in concrete will not only facilitate an environmentally sustainable solution to solid waste disposal but also will significantly contribute to alleviating the ever-growing demand for natural aggregates in concrete production. However, only limited studies focused on the use of rubberized recycled aggregate concrete (RRAC), which lacks in-depth scrutinization of its material behavior with respect to conventional concrete. The first stage of this study is focused on investigating the effect of pre-treatment of crumb rubber (CR) with three levels of NaOH concentration on rubberized mortar specimens. The second stage consists of an experimental investigation on the mechanical behavior of concrete comprising CR and recycled concrete aggregate (RCA) each at three replacement levels of natural fine and coarse aggregates, respectively, at a water-cement ratio (w/c) of 0.34. The results indicate RRAC yields satisfactory compressive and flexural behavior for use in structural concrete.

DOI:

10.14359/51722409


Document: 

19-206

Date: 

May 1, 2020

Author(s):

Anwar Al-Yaqout, Moetaz El-Hawary, Khallad Nouh, and Pattan Bazieth Khan

Publication:

Materials Journal

Volume:

117

Issue:

3

Abstract:

The main objective of this paper is the investigation of the corrosion resistance of reinforced concrete containing various proportions of recycled aggregates (RA) combined with 25% ground-granulated blast-furnace slag (GGBS) as a partial cement replacement. An accelerated corrosion system was designed to test the steel corrosion in reinforced concrete by subjecting the samples to 150 and 300 wetting-and-drying cycles. The results, in general, showed that the use of RA in concrete mixtures was found to reduce the compressive strength, increase chloride penetration, decrease the corrosion potential of reinforcing bars, reduce the electrical resistance of concrete, and hence increase the corrosion risk. However, better results were achieved by the addition of 25% GGBS, which increased the core compressive strength and electrical resistance. Moreover, better results were achieved for normal and slag mixtures that have 0.788 in. (20 mm) concrete cover than those having 0.394 in. (10 mm) cover.

DOI:

10.14359/51722406


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