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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 14 Abstracts search results
Document:
23-368
Date:
January 1, 2025
Author(s):
Andrzej Seruga and Marcin Dyba
Publication:
Structural Journal
Volume:
122
Issue:
1
Abstract:
This paper examines the bond behavior between non-pretensioned plain steel wire and high-performance concrete (HPC). It investigates the effects of embedment length and concrete compressive strength on bond performance for the production of railway sleepers. To determine the performance, pullout concrete specimens reinforced with 7 mm diameter plain steel wire were cast and tested under a uniaxial load. The main test parameters include the embedment length: 40, 80, 120, 240, 330, and 460 mm; and concrete compressive strength: 40, 60, 72, and 88 MPa. The modified pullout test method developed at Cracow University of Technology was used in the experimental investigation. The study unequivocally demonstrates that the maximum bond stress between HPC and a non-pretensioned plain steel wire with a diameter of 7 mm decreases as the embedment length increases, irrespective of the concrete’s compressive strength. Furthermore, it was observed that the average bond stress increases with an increase in the concrete’s compressive strength with time. After conducting tests on HPC specimens with compressive strengths ranging from 60 to 88 MPa and embedment lengths ranging from 40 to 120 mm, it was determined that the resulting maximum adhesion bond stress was 2.22 MPa. This was 52% higher than the bond stress found in test pieces made of concrete with fcm = 40 MPa. Additionally, the average residual bond stress was found to be twice that of concrete with a compressive strength of 40 MPa. These findings demonstrate a clear advantage of using HPC in terms of bond stress.
DOI:
10.14359/51742145
23-330
September 1, 2024
Peiyuan Chen, Chunning Pei, Liheng Zhang, Shangkun Li, and Jialai Wang
Materials Journal
121
5
The applications of alkali-activated slag (AAS) face challenges such as poor workability, rapid setting, and high autogenous shrinkage, which require chemical admixtures (CAs) to adjust the performance of AAS. Unfortunately, there are limited specific CAs available to tune AAS properties. To address this gap, this study proposes using a ubiquitous, naturally occurring compound, L-ascorbic acid (LAA), as a multifunctional performanceenhancing additive for AAS to overcome the major challenges of AAS. The findings showed that LAA can function as a retarder, plasticizer, strength enhancer, and autogenous shrinkage reducer for AAS. When 0.5% LAA was added, the compressive strengths of AAS mortars at 3 and 28 days increased by 28.9% and 19.6%, respectively, and the 28-day autogenous shrinkage decreased by 43.1%. Both surface adsorption and ion complexation have been confirmed as the working mechanisms of LAA in hydrated AAS.
10.14359/51742041
18-330
July 1, 2019
Boyan I. Mihaylov, Jian Liu, Konstantine Simionopoulos, Evan C. Bentz, and Michael P. Collins
116
4
Eight post-tensioned beams were tested at the University of Toronto to study the size effect in shear and the influence of different tendon layouts. The specimens varied in depth from 250 to 1000 mm (9.84 to 39.4 in.), while the unbonded tendons were either straight or harped. The eccentricity of the tendons was either zero, 1/6, or 1/2.67 of the section depth. The beams had no stirrups and were tested to shear failure under symmetrical three-point bending. It is shown that the specimens with a shear-span-to-effective-depth ratio of approximately 3 developed arch action and exhibited a size effect. A strut-and-tie model based on the AASHTO code captures the experimental results well, except the high shear resistance observed in the smallest specimens. To explain this behavior and the transition from slender to deep members, the paper sets the basis of a rational modeling approach based on kinematics. It is shown that the complete deformation patterns of the beams, including the width of the shear cracks, can be captured by a kinematic model with only three degrees of freedom.
10.14359/51715633
16-330
July 1, 2017
Kenichiro Nakarai, Yuko Ogawa, Kenji Kawai, and Ryoichi Sato
114
Use of limestone aggregate has been recently increasing to improve material properties such as shrinkage reduction. However, limestone aggregate may cause brittle failure of concrete and concrete structures. Therefore, this study compared the fracture properties of normal-strength concrete and the shear strength of reinforced concrete (RC) beams with limestone aggregate with those with rhyolite aggregate as the reference. The results showed that the shear strength of the limestone aggregate concrete beam was on an average approximately 24% less than that of the reference beam and it was only 57% of the ACI Code calculation at the minimum. The reduction was explained by the fracture properties of limestone aggregate concrete: small characteristic length with low fracture energy. The relationship between normalized shear strength and characteristic length, which was originally proposed based on the numerical studies, showed a trend similar to high-strength concrete, which was experimentally investigated.
10.14359/51689725
15-330
May 1, 2017
A. Muthadhi and V. Dhivya
3
To address the environmental constraints due to cement production and sand scarcity, strength properties of high-calcium fly ash (CFA)-based geopolymer concrete with quarry dust as fine aggregate is explored in this paper. River sand was replaced with quarry dust from 0 to 100% by mass. Sodium hydroxide solution with 8M and 14M concentration, alkaline liquid-to-fly ash ratios of 0.50 and 0.60, and three curing regimes—oven curing, ambient curing, and external exposure curing—were used. The results indicated that geopolymer concrete achieved comparably equal strength to that of the reference concrete mixture at a 100% quarry dust level. External exposure and ambient curing can be practiced to attain comparable strength properties of geopolymer concrete with quarry dust as fine aggregate. Experimental values of split tensile strength of geopolymer concrete with quarry dust follows good relations with various empirical equations.
10.14359/51689674
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