scholarly journals Compression Behavior of Confined Columns with High-Volume Fly Ash Concrete

2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Sung-Won Yoo ◽  
Young Cheol Choi ◽  
Wonchang Choi
Keyword(s):  
Reinforced Concrete ◽  
Fly Ash ◽  
Construction Material ◽  
Concrete Columns ◽  
High Volume ◽  
Analysis Model ◽  
Replacement Rate ◽  
Reinforced Concrete Columns ◽  
High Volume Fly Ash ◽  
Structural Applications

The use of fly ash in ordinary concrete provides practical benefits to concrete structures, such as a gain in long-term strength, reduced hydration heat, improved resistance to chloride, and enhanced workability. However, few studies with high-volume fly ash (HVFA) concrete have been conducted that focus on the structural applications such as a column. Thus, there is a need to promote field applications of HVFA concrete as a sustainable construction material. To this end, this study investigated the compressive behavior of reinforced concrete columns that contain HVFA with a 50 percent replacement rate. Six columns were fabricated for this study. The study variables were the HVFA replacement rate, tied steel ratio, and tie steel spacing. The computed ultimate strength by the American Concrete Institute (ACI) code conservatively predicted the measured values, and, thus, the existing equation in the ACI code is feasible for confined RC columns that contain HVFA. In addition, an analysis model was calibrated based on the experimental results and is recommended for predicting the stress-strain relationship of confined reinforced concrete columns that contain HVFA.

scholarly journals Mechanical Properties of High-Volume Fly Ash Strain Hardening Cementitious Composite (HVFA-SHCC) for Structural Application

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2607 ◽  
Author(s):  
Chenhua Jin ◽  
Chang Wu ◽  
Chengcheng Feng ◽  
Qingfang Zhang ◽  
Ziheng Shangguan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Strain Hardening ◽  
Construction Material ◽  
High Volume ◽  
Partial Replacement ◽  
Cementitious Composite ◽  
Multiple Cracking ◽  
High Volume Fly Ash ◽  
Structural Applications

Strain-hardening cementitious composite (SHCC) is a kind of construction material that exhibits multiple cracking and strain-hardening behaviors. The partial replacement of cement with fly ash is beneficial to the formation of the tensile strain-hardening property of SHCC, the increase of environmental greenness, and the decrease of hydration heat, as well as the material cost. This study aimed to develop a sustainable construction material using a high dosage of fly ash (no less than 70% of the binder material by weight). Based on the micromechanics analysis and particle size distribution (PSD) optimization, six mixes with different fly ash to cement ratios (2.4–4.4) were designed. The mechanical properties of the developed high-volume fly ash SHCCs (HVFA-SHCCs) were investigated through tensile tests, compressive tests, and flexural tests. Test results showed that all specimens exhibited multiple cracking and strain-hardening behaviors under tension or bending, and the compressive strength of the designed mixes exceeded 30MPa at 28 days, which is suitable for structural applications. Fly ash proved to be beneficial in the improvement of tensile and flexural ductility, but an extremely high volume of fly ash can provide only limited improvement. The HVFA-SHCC mix FA3.2 (with fly ash to binder ratio of about 76% by weight) designed in this study is suggested for structural applications.

Evaluation of Compressive and Shear Strength Characteristics in High Volume Fly Ash Concrete

2014 ◽  
Vol 584-586 ◽  
pp. 1282-1288 ◽  
Author(s):  
Sung Won Yoo ◽  
Sang Hwa Jung ◽  
Seung Jun Kwon
Keyword(s):  
Shear Strength ◽  
Fly Ash ◽  
Construction Material ◽  
Cost Benefit ◽  
High Volume ◽  
Engineering Properties ◽  
Fly Ash Concrete ◽  
High Volume Fly Ash ◽  
Basic Parameters ◽  
Paper Engineering

HVFAC (High Volume Fly Ash Concrete) is an attractive construction material with cost benefit and reduced CO2emission. In this paper engineering properties such as compressive and shear strength are evaluated and their characteristics are investigated. For this work HVFAC with FA (Fly Ash) replacement ratio of 35% and 50% are prepared and strength (compressive, shear, and bond) are measured with basic parameters like elasticity and ultimate strain. Test results are compared with conventional predictions from Korea Structural Code and their applicabilities are evaluated. In bond strength and elasticity in HVFAC are evaluated to need reasonable coefficients for HVFAC design.

Nanosilica Activated High Volume Fly Ash Concrete: Effects on Selected Properties

2016 ◽  
Vol 722 ◽  
pp. 157-162 ◽  
Author(s):  
Martin Labaj ◽  
Rudolf Hela ◽  
Iveta Hájková
Keyword(s):  
Fly Ash ◽  
Raw Materials ◽  
Water Pressure ◽  
Construction Material ◽  
High Volume ◽  
Strength Development ◽  
Early Age ◽  
Fly Ash Concrete ◽  
High Volume Fly Ash ◽  
Static And Dynamic Moduli

By volume, there is no other material used as much as concrete. Its mechanical properties, durability and favorable price makes concrete the perfect construction material. In last few decades, we are seeing a growing trend of partial Portland cement’s replacement with secondary raw materials, most commonly with fly ash. So-called high volume fly ash (HVFA) concretes usually contains over 50% of it. While HVFA concrete’s long-term properties and price are improved over the classical one, its early age properties are often affected negatively. Here, a highly reactive pozzolans enters the scene. Materials like microsilica and metakaolin are known to accelerate concrete’s strength development and improve early age characteristics. In this paper, nanosilica is used for this purpose. These SiO2 nanoparticles possesses a much higher surface area and thus reactivity. Three mixtures with 0, 40 a 60% portland cement’s replacement with fly ash were prepared and tested with and without addition of small amount of nanosilica. Effects on compressive strength, static and dynamic moduli of elasticity and resistivity against water pressure were observed. Results clearly demonstrates that even with dosage in the range of tenths of percent, nanosilica can significantly improve concrete’s properties.

scholarly journals Comprehensive Investigation on the Potential of Fly Ash from New Source as Construction Material

2021 ◽  
Vol 23 (2) ◽  
pp. 78-90
Author(s):  
Antoni Antoni ◽  
Florentcia Hartono ◽  
Steven Tanuwijaya ◽  
Kevin Wijaya ◽  
Agie Vianthi ◽  
...  
Keyword(s):  
Fly Ash ◽  
Calcium Hydroxide ◽  
Alkaline Solution ◽  
Construction Material ◽  
High Volume ◽  
Comprehensive Investigation ◽  
Good Source ◽  
Cement Replacement ◽  
High Volume Fly Ash ◽  
Very High

Fly ash has been highly advocated to be re-utilized as a construction material. The most common utilization is to partially replace cement in a low-percentage scheme. However, there are several other schemes available to potentially use fly ash as binder in concrete that have not been widely exercised, especially those utilizing it in high to very high volume. In those schemes, high-volume fly ash (HVFA) concrete might use more than 50% fly ash to replace cement. To exploit its self-cementing properties, with or without the addition of other compounds, such as calcium hydroxide, fly ash might be used in very high percentage of cement replacement. In geopolymeric system, fly ash acts as the precursor of a stable binder, with the presence of highly alkaline solution. This paper demonstrates a model to investigate the potential of fly ash in several binder systems. The results show that fly ash from a good source can be utilized as an alternative binder in several different schemes.

BEHAVIOR OF PLAIN AND STEEL FIBER HIGH STRENGTH REINFORCED CONCRETE COLUMNS CONFINED WITH CFRP

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Duygu Erturkmen ◽  
Cengiz Dundar ◽  
Serkan Tokgoz
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Steel Fiber ◽  
High Strength ◽  
Concrete Columns ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Reinforced Concrete Columns ◽  
Strength Capacity ◽  
Structural Applications

High strength reinforced concrete columns have been increasingly used in structural applications. It is known that high strength reinforced concrete columns exhibit brittle behavior under applied loads. Therefore, steel fibers can be added into the core concrete to improve the ductility and deformability of high strength reinforced concrete columns. In addition, reinforced concrete columns can be wrapped with carbon fiber reinforced polymer (CFRP) materials for strengthening the columns. In this work, experimental and analytical studies on plain and steel fiber reinforced concrete columns and CFRP confined columns have been presented. The experimental strength capacities, load-deflection relations and failure modes of the column specimens have been observed. The effects of the parameters of concrete compressive strength, load eccentricity, steel fibers, and carbon fiber polymer material on the structural behavior of high strength reinforced concrete columns have been examined. It is concluded that the inclusion of steel fibers has considerable effect on column ductility and deformability, but has insignificant effect on column strength capacity. The experimental study exposed that wrapping CFRP material on plain and steel fiber high strength reinforced concrete columns has provided significant improvement on the column strength capacity and confinement. The tested columns have been analyzed with a theoretical method considering the experimental stress-strain relations of CFRP confined concrete; and the analysis shows good agreement with the experimental results.

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