ABSTRACT
This study is part of an extensive on-going experimental investigation on the mechanical properties of HESFRC. HESFRC is defined here as achieving a minimum compressive strength of 5 ksi (35 MPa) at 24 hours. This paper discusses the compressive properties and elastic modulus of the hardened HESFRC composite with time. The properties of the fresh composite are not described here due to space limitations, but can be found elsewhere (Naaman and Alkhairi 1991). The effects of latex and silica fume were investigated and compared to plain HESFRC. Two fiber types were used, namely, hooked end steel and polypropylene fibers. For the hooked steel fibers, two aspect ratios were examined corresponding to 30/50 fibers (i.e., 30 mm long and 0.05 mm in diameter) and 50/50 fibers (i.e., 50 mm long and 0.05 mm in diameter). Several combinations of fiber types were examined using 1% and 2% fibers by volume of the concrete mix. Test results include the overall stress-strain response, the compressive strength, and the elastic modulus, all measured at 1, 3, 7, and 28 days. The requirement for HESFRC mixes of achieving a compressive strength of 5 ksi (35 MPa) or greater at 1 day was generally satisfied by all mixes except those containing polypropylene fibers and/or latex. In all, 16 different mixes were investigated comprising 220 specimens.
