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

Sung-Won Yoo,Young Cheol Choi,Wonchang Choi

doi:10.1155/2017/8208079

Sung-Won Yoo, Young Cheol Choi + Show 1 more

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https://doi.org/10.1155/2017/8208079

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Abstract

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.

Highlights

Fly ash is an industrial byproduct of the electrical power industry
Fly ash content that is less than 25 percent of the total cementitious content is commonly used in concrete mixtures due to its apparent benefits for concrete, such as a gain in long-term strength, reduced hydration heat, improved resistance to chloride, and enhanced workability [1,2,3,4]
Most of the previous studies on this topic have concentrated on evaluating the material properties of high-volume fly ash (HVFA) concrete and developing mix designs [3, 7]

Summary

Introduction

Fly ash is an industrial byproduct of the electrical power industry. Recently, partially recycled fly ash has been used as supplementary cementitious material in the cement industry. An increase up to a 100 percent fly ash replacement rate in concrete mixtures has been attempted [5] This increase in the replacement rate of cement has led to shortcomings, such as difficulties associated with adequate quality control and low early-age strength and inferior material properties [6]. Most of the previous studies on this topic have concentrated on evaluating the material properties of high-volume fly ash (HVFA) concrete and developing mix designs [3, 7]. Huang et al [8] confirmed the superior mechanical properties of mixtures with low LOI fly ash and the feasibility of incorporating HVFA in concrete mixtures up to 80 percent. Limited studies have been conducted that target the use of HVFA for structural applications [9,10,11,12]

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