Precast Inc. - November/December 2008 - (Page 28) B BOOTH 1839 THE PRECAST SHOW A D C FIGURE 3: QUALITY CONTROL OF SCSFRC PRECAST ROOF ELEMENTS: FIBER CONTENT IN THE FRESH STATE (A); ELEMENT DEMOLDING (B); SCHEME FOR CORE DRILLING ALONG THE ELEMENT (C); AND FIBER CONTENT ALONG THE ELEMENT DURING MANUFACTURING (D). nondestructive test methods for the in-place monitoring of fiber dispersion. Role of fiber dispersion and orientation on crack resistance A more effective dispersion of fibers can be achieved with SCC matrices. It is important to minimize areas in the mix with reduced or no fibers. SCSFRC exhibits more resistance to cracking than SCC. The orientation of the fibers, as affected by the fresh concrete flow during specimen manufacturing and element casting, is another major factor affecting the toughness, or crack resistance, of SCSFRC. Recent results have shown by maintaining a consistent viscosity in fresh concrete, fibers can be effectively oriented along the flow direction. In order to optimize structural performance, it is important that fibers are aligned in the direction of the principal tensile stresses within the structural element when in service (Figure 7). Orienting fibers in the direction of tensile stresses in service leads to a more efficient structural use of materials, 28 NOVEMBER/DECEMBER 2008 | PRECAST INC. and to reduced structure size and self weight. Lighter and smaller precast elements translate into reduced transportation and erection costs for the precast construction industry. Proposed solutions: synergy between academia and industry This article summarizes the most significant research findings and applications dealing with SCSFRC. SCSFRC is shown to be a “smart” construction material particularly for precast concrete applications. A review of some structural SCSFRC case studies was instrumental at identifying issues that deserve further investigation. Working together, industry and academia can develop a synergy to achieve more cost-effective precast solutions, as follows: 1. Establish quality control procedures for fresh-state SCSFRC. 2. Monitor fiber dispersion-related issues crucial for reliable structural applications of fiber-reinforced http://www.muka.net http://www.muka.net
For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.