Abstract
This program was carried out to investigate the effect of various steel fibers on mechanical strength and deformation characteristics of fiber reinforced polymer-impregnated concrete (FPIC) polymerized by gamma-rays under water (dose rate: 1×106R/hr, 5MR). Tested steel fibers consist of four kinds of fibers each with 0.35mm diameter, piano wire, stainless steel, annealed stainless steel and low carbon steel (Table I). Fiber quantity and fiber length were varied within the range of F/C=5∼20% and length of 35mm or 150mm. Crimping effects of steel fiber which was trially formed to tridimensional waves (Fig. 1) were examined, and compared with normal straight fiber.
Among the seven kinds of fiber examined, the straight piano wire was the most effective on increasing strength and plastic deformation of FPIC, and straight low carbon steel fiber was the most useful for fiber reinforced concrete with no polymer (FRC). However, the tempering process of stainless steel fiber had no beneficial effect (Fig. 5), and crimping of the fiber had the worse effects compared with normal straight one (Fig. 6).
Steel fiber has a remarkable contribution to increase the impact strength of PIC, and straight piano wire gives the wide plastic range to the deformation of PIC and also gives large toughness Eu especially (Figs. 11 and 12). Ultimate flexural, compressive, tensile and Charpy's impact strengths and toughness of FPIC with F/C=15%, were as follows; σb=586, σc=2283, σt=180, σimp=277kg /cm2 and Eu=40.3kg·cm/cm2. These values are 7.2, 4.2, 3.0, 24.3 and 192 times as large as those of control samples, respectively.
