ORCID Identifier(s)

0000-0002-3448-6358

Graduation Semester and Year

2017

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Civil Engineering

Department

Civil Engineering

First Advisor

Ali Abolmaali

Abstract

This study investigates the long-term influence of polypropylene fibers on the shear strength and failure behavior of longitudinally reinforced concrete beams, with or without stirrups, subjected to accelerated aging conditions. For this study, 32 large scale short beams with different volume fractions of polypropylene fibers were casted and tested in the Civil Engineering Laboratory Building (CELB) at the University of Texas at Arlington: (1) Control reinforced concrete beams (RC); (2) Reinforced concrete beams with minimum stirrups (RCS) according to ACI 318; (3) Synthetic fiber-reinforced concrete beams with Vf=0.5% (SNFRC 0.5%), which correspond to 7.67 lbs./yd3 (4.55 kg/m3)’; and (4) Synthetic fiber-reinforced concrete beams with Vf=0.75% (SNFRC 0.75%), which correspond to 11.5 lbs/yd3 (6.82 kg/m3). In addition, a total of 108 cylindrical specimens, 4 in. (102mm) in diameter and 8 in. (203mm) in height, were tested after 28 days, 1 month, 3 months, and 6 months after curing, and were subjected to accelerated aging conditions in an environmental chamber at 122˚F (100% relative humidity). Moreover, a total of 36 flexural beam specimens, 6 in. (152mm) wide and high were produced and tested at CELB. A 3-D non-linear finite element model (FEM) with concrete damage plasticity (CDP) was considered to analyze the failure of the large-scale reinforced concrete beams. All of the experimental large-scale beam results were verified using FEM software. The concrete constitutive law in tension and compression of the experimental data were found with inverse analysis and trial and error to model the shear behavior of the concrete beams. The concrete constitutive law in tension and compression, using FEM in 100 years, were developed to predict the long-term behavior of the concrete beams. The essential modeling parameters for shear capacity of large-scale beams with different volume fractions of polypropylene fibers for regression analysis were identified. Finally, a shear design equation was developed for the concrete beams, with a different volume fraction of polypropylene fibers in 100 years.

Keywords

Shear, Long-term, Concrete beams, Accelerated aging, Arrhenius, Polypropylene fibers, Synthetic fibers

Disciplines

Civil and Environmental Engineering | Civil Engineering | Engineering

Comments

Degree granted by The University of Texas at Arlington

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