Mechanical properties of ultra-high-performance hybrid polyethylene-steel fiber reinforced concrete

• Main Author: Liao, Se Wei
• Other Authors: Tan Kang Hai
• Format: Final Year Project
• Language: English
• Published: 2017
• Subjects: DRNTU::Engineering::Civil engineering
• Online Access: http://hdl.handle.net/10356/70954
• Institution: Nanyang Technological University

The effects of combined fibers on the various characteristics and behaviors of Ultra High Performance Fiber Reinforced Concrete (UHPFRC) were investigated. Polyethylene (PE) and steel fibers were used. In producing the specimens, the volume content of polyethylene was varied from 0.0% to 1.0% (with an interval of 0.5%) and the volume content of steel fibers was varied from 0.0% to 2.0% (with an interval of 1.0%). The addition of polyethylene result in a slight reduction of compressive strength. The presence of steel fibers did not reduce the compressive strength. The combination of the two types of fiber favorably affects the flexural behavior of UHPC compared to the mix design with only one type of the fibers. UHPFRC with 0.5% polyethylene and 2.0% steel fibers exhibited the best overall performance considering the compressive, tensile and flexural properties. In addition, crucial mix proportion parameters i.e. the water to binder ratio and aggregate size were studied. The flexural behavior was also studied under elevated temperature. A slight increase in aggregate size from 0.6 mm to 2.3 mm has a positive influence on the mechanical properties of UHPFRC. On the contrary, the increase in water content will negatively affect the mechanical properties of concrete. The UHPFRC spalled even at a very low heating rate, which proves PE fibers cannot help to prevent spalling. However, for the specimens did not spall, the elevated temperature enhanced the flexural property.