Effects of transition zone densification on fiber/cement paste bond strength improvement

✍ Scribed by Yin-Wen Chan; Victor C. Li

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 900 KB
• Volume: 5
• Category: Article
• ISSN: 1065-7355
• DOI: 10.1016/s1065-7355(97)90010-9

✦ Synopsis

This paper investigates the effectiveness of transition zone densification on the fiber-cement paste system. By controlling the water: cement (w:c) ratio and the condensed silica fume content, environmental scanning electron microscopy studies confirm that transition zone densification can be achieved in all brass, steel, and polyethylene fiber-cement systems. However, single fiber pullout tests indicate that densification only enhances the brass-cement paste interface bond strength and not the other systems. Further microscopy investigation of the surface of fibers peeled off from a composite fracture surface and of the groove left by the fiber on the cement paste suggests that bond failure for the brass-cement system is of a cohesive type, whereas bond failure for the other two systems is of an adhesive type. It is concluded that the transition zone densification technique should be effective in fiber-cement systems in which bond strength is controlled by cohesive failure of the transition zone material.