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 research pursues a comprehensive experimental study on the shear capacity of zero-slump, dry-cast Synthetic Fiber-Reinforced Concrete (SYN-FRC) with the aim of reducing or even eliminating stirrups in box culverts. Since using stirrups in structures such as box culverts need labor work and cause reinforcement congestion, eliminating or reducing stirrups in design, prevent poor-quality concrete, help better concrete compaction and could save manufacturer time and money over the years. This study first determined the shear capacity of synthetic fiber concrete matrix by varying fiber volume fraction. Then, FEA and full experimental tests have been conducted to evaluate the effect of using synthetic fiber in increasing the shear capacity of box culverts. Japan Society of Civil Engineers (JSCE) G-553 test method has been selected for evaluating the shear behavior of synthetic fiber reinforced concrete. In adjacent with shear test, flexural and compression behavior of concrete determined based on ASTM C1609 and ASTM C39, respectively. To investigate the effect of different concrete compressive strengths on material properties of synthetic fiber-reinforced concrete, two different concrete compressive strength values, 28 MPa (4,000 psi) and 34 MPa (5,000 psi) were selected. Two major phases were considered to complete the study, which included: (1) Material test for two different concrete compressive strength values (4000 and 5000 psi) and developing shear strength for 7000 psi concrete compressive strength with different fiber volume fractions by using Finite Element Analysis (FEA); (2) Finite Element Modeling (FEM) on all of the ASTM C1577 box culverts equipped with different synthetic fibers dosage (260 cases) along with experimental tests on 5 full-scale box culverts in order to evaluate the FEM results. The first phase is consist of three different material tests with more concentration on shear test. Since there is no standard shear test method documented in American Society for Testing and Materials (ASTM), therefore the Japan Society of Civil Engineering (JSCE) test method (with some alterations) was selected for extracting shear properties of SYN-FRC. The concrete used in this study was zero-slump, dry-cast one which is typically used for mass productions like concrete pipe, manhole and box culverts. The total number of 60 beams have been tested based on JSCE-G553 and ASTM C1609 for two different concrete compressive strength values. After finishing the material tests, Finite Element Analysis (FEA) has been conducted for developing the shear strength of 7000 psi concrete compressive strength with different fiber volume fractions and also to capture the tensile behavior of concrete equipped with different fiber volume fractions. In order to calibrate the material model defined in ABAQUS, the results of FEM were compared with experimental data. After implementing phase I, phase II started which had more focus on the shear behavior of box culverts equipped with synthetic fiber along with conventional reinforcement. Different sizes of box culverts have been modeled in FEM by considering plain concrete and also synthetic fiber reinforced concrete. For evaluating the accuracy of FEM results, full-scale tests have been conducted with optimum synthetic fiber volume fraction in concrete. The test and FEM results demonstrated that the application of synthetic fibers in concrete yielded to significant improvements in material and structural behavior of concrete and these enhancements were greater at higher synthetic fiber dosage rates.

Keywords

Shear behavior, Synthetic fibers, Box culverts, Finite element analysis, Experimental tests, Material test

Disciplines

Civil and Environmental Engineering | Civil Engineering | Engineering

Comments

Degree granted by The University of Texas at Arlington

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