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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 36 Abstracts search results
Document:
21-477
Date:
September 1, 2022
Author(s):
Jae Hong Kim, Tae Yong Shin, Cho-Bum Park, and Chan Kyu Park
Publication:
Materials Journal
Volume:
119
Issue:
5
DOI:
10.14359/51735979
20-502
November 1, 2021
Flavia Mendonca and Jiong Hu
118
6
Abstract:
Ultra-high-performance concrete (UHPC) is a new class of cementitious material with unique characteristics, including self-consolidation, and excellent mechanical and durability properties. To achieve the desired properties, a very dense internal structure and a very low water-binder ratio (w/b) are necessary. Due to the very different mixture design compared to conventional concrete, it is critical to incorporate different types of chemical admixtures to achieve appropriate fresh concrete behavior of UHPC. To ensure the successful placement of UHPC, it is important to have a good understanding of the workability and rheological characteristics of UHPC with different types and dosages of chemical admixtures. This paper presents a detailed study of the impact of high-range water reducer, workability-retaining admixture, and anti-foaming admixture on the workability and rheological characteristics over different mixture elapsed times. Besides the flowability, both Bingham and modified Bingham models were used to obtain key rheological parameters, including yield stress, viscosity, and thixotropy. Furthermore, the authors developed stability indexes to assess the fiber stability of UHPC in both fresh and hardened states. Based on the experimental results, the paper presented suggested criteria to ensure appropriate flowability and fiber stability for UHPC placement.
10.14359/51734151
20-207
May 1, 2021
Lihe Zhang, Dudley R. Morgan, Iain Kirk, Anastasia Rolland, and Robert Karchewski
3
Wet-mix shotcrete has been used more and more for structural applications in the past few decades. Recently, wet-mix shotcrete was successfully used to construct a mass structural wall with congested reinforcement and minimum dimensions of 1.0 m in a sewage treatment plant. A low-heat shotcrete mixture that included up to 40% slag was proposed for shotcrete application. A preconstruction mockup was shot to established proper work procedures for shotcrete application and qualify the shotcrete mixture and shotcrete nozzlemen. Extraction of cores and cut windows from the mockup confirmed proper consolidation around the congested reinforcement. A thermal control plan was developed, which included laboratory and field testing requirements, thermal analysis modeling with a three-dimensional (3-D) finite element program, and thermal control requirements, including installation of cooling pipes and thermal blankets. Shotcrete proved to be an efficient means for mass concrete structural construction. Thermal control for mass shotcrete construction was studied, and the proposed thermal control plan was proved to function properly. The general guidance for mass shotcrete construction is provided.
10.14359/51730423
19-232
May 1, 2020
Mohamed M. Sadek, Mohamed K. Ismail, and Assem A. A. Hassan
117
This study aimed to optimize the use of fine and coarse expanded slate lightweight aggregates in developing successful semi-lightweight self-consolidating concrete (SLWSCC) mixtures with densities ranging from 1850 to 2000 kg/m3 (115.5 to 124.9 lb/ft3) and strength of at least 50 MPa (7.25 ksi). All SLWSCC mixtures were developed by replacing either the fine or coarse normal-weight aggregates with expanded slate aggregates. Two additional normal-weight self-consolidating concrete mixtures were developed for comparison. The results indicated that due to the challenge in achieving acceptable self-consolidation, a minimum binder content of at least 500 kg/m3 (31.2 lb/ft3) and a minimum water-binder ratio (w/b) of 0.4 were required to develop successful SLWSCC with expanded slate. The use of metakaolin and fly ash were also found to be necessary to develop successful mixtures with optimized strength, flowability, and stability. The results also showed that SLWSCC mixtures made with expanded slate fine aggregate required more high-range water-reducing admixture than mixtures made with expanded slate coarse aggregate. However, at a given density, mixtures developed with expanded slate fine aggregate generally exhibited better fresh properties in terms of flowability and passing ability, as well as higher strength compared to mixtures developed with expanded slate coarse aggregate.
10.14359/51722407
18-006
January 1, 2019
Mohamed K. Ismail, Assem A. A. Hassan, and Mohamed Lachemi
116
1
This investigation aims to study the abrasion resistance of developed self-consolidating engineered cementitious composite (SCECC) mixtures using the rotating-cutter and sandblasting abrasion tests. The fresh and mechanical properties of the developed SCECC were also investigated in this study. Additional conventional self-consolidating concrete (SCC) (with 10 mm [0.39 in.] coarse aggregate) and vibrated engineered cementitious composite (VECC) mixtures were tested for comparison. The standard engineered cementitious composites (ECCs) are commonly developed using a high volume of fly ash (FA) and microsilica sand (SS). In this study, the FA was partially replaced by varied volumes of slag (SL), silica fume (SF), and metakaolin (MK), while the SS was replaced by crushed granite sand (CS) of different sizes. The results indicated that combining SL, SF, or MK with FA resulted in developing SCECCs with adequate deformability and higher abrasion resistance, compressive strength, and flexural strength. Using 20% of MK in the development of SCECC showed the best abrasion resistance improvement in both rotating-cutter and sandblasting tests. The results of rotating-cutter and sandblasting tests also indicated that SCECC mixtures appeared to have less abrasion resistance compared to their SCC counterpart mixtures with 10 mm (0.39 in.) coarse aggregate.
10.14359/51712239
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