Ph.D. Student Alena Mikhaylova with the first Steel Fiber Reinforced Concrete Pipe produced at UT Arlington in the United States

This study aims at developing AASHTO and ASTM performance-based specifications for SFRCP through extensive experimental studies and finite element analyses. The concrete mix design, including Dramix steel fiber as an ingredient, will be developed and pipes will be manufactured at four of the largest pipe production facilities throughout the United States. These facilities are: Hanson Pipe and Precast in Grand Prairie, Texas; Rinker-Materials in Orlando, Florida; the Northern Concrete Pipe in Bay City, Michigan; and Sherman Dixie Concrete Industries in Lexington, Kentucky. Different production techniques and tools such as packerhead, pedershaab Hawkeye, and Schlusslebauer will be employed. The Co-PIs of this project are Dr. Pranesh Aswath of Material science and Engineering, Dr. Simon Chao, and Dr. Tri Le of Civil Engineering at UT Arlington.

The experimental phase of this study will include both material and full-scale structural tests to include different pipe diameters ranging from 12 in. to 72 in. Three-edge bearing tests (D-Load) will be conducted on all the instrumented test specimens to monitor strength, stiffness, crack initiation, and crack propagation. The mix design will be optimized and production manuals will be developed for different production processes listed above.

The scanning electron microscope (SEM) images of the fiber distribution in dry-cast concrete will be taken using a JSM-IC 845A microscope from Professor Aswath's laboratory at the Material science and Engineering Department at UT Arlington. In addition, optical stereomicroscopy (Nikon Stereomicroscope) will be used to characterize distribution of the steel fibers in the matrix. The interfacial properties of fiber and concrete will be determined by using a combination of nanoindentation and microindentation.

Complete nonlinear three dimensional finite element models (FEM) of steel fiber concrete pipes will be developed and compared with experimental tests for model verification. Also, the significance of crack width affecting pipe stiffness characteristics will be modeled by using tension-stiffening constitutive relationship for steel-fiber concrete. The FEM simulation will predict the full-scale tests up to failure by using a scaled mass dynamic algorithm coupled with discrete crack model for steel fiber concrete.