Accession Number : AD1037917

Title :   Effect of Fiber Orientation on Dynamic Compressive Properties of an Ultra-High Performance Concrete

Descriptive Note : Technical Report

Corporate Author : U.S. Army Engineer Research and Development Center Vicksburg United States

Personal Author(s) : Groeneveld,Andrew B ; Ahlborn,Theresa M ; Crane,C K ; Long,Wendy R

Full Text :

Report Date : 01 Aug 2017

Pagination or Media Count : 133

Abstract : Casting structural elements with ultra-high performance concrete (UHPC) tends to create preferential fiber alignment, which affects the strength and must be accounted for in design. To date, most work on fiber-orientation effects has been in tension rather than compression. This work characterizes the fiber orientation occurring in a typical UHPC beam and how that orientation affects compressive behavior at high strain rates. Specimens (36 total) were cored from the beam, and their fiber orientations were non-destructively evaluated using x ray computed tomography. Fibers showed flow-induced alignment along the length of the beam. The perpendicular orientation number was used to describe orientation, as fibers perpendicular to the load were most effective in crack bridging. Quasi-static compressive strength appeared to increase with perpendicular orientation number, but the correlation is uncertain due to data limitations. Dynamic tests at strain rates of 130 to 200 s-1 were performed with a split-Hopkinson pressure bar. Dynamic compressive strength was independent of orientation number in these tests, although results suggested that the distribution and orientation of fibers influenced crack formation. The strain at peak stress, a measure of ductility, increased up to 25 percent over the range of perpendicular orientation numbers tested.

Descriptors :   High performance concrete , Castings , materials testing , xray computed tomography , dynamic tests , stresses , stress strain relations , Strain

Subject Categories : Ceramics, Refractories and Glass
      Military Forces and Organizations

Distribution Statement : APPROVED FOR PUBLIC RELEASE