Fiber reinforced grancrete strengthening system

Abstract

This paper summarizes the research undertaken to investigate and evaluate the effectiveness of a new proposed strengthening system called "Fiber Reinforced Grancrete (FRG)". Grancrete is a new cementitious material that resists fire; it can be used as a sprayable coating for protection of structures from severe environmental conditions and for strengthening of existing structural elements. Grancrete has excellent adhesive strength characteristics which lead to this study. Strengthening of reinforced concrete (RC) structures with externally bonded FRP composites has become very popular over the past decade due to its well-known advantages in comparison to conventional construction materials. The combination of the Grancrete as a matrix reinforced with FRP, as the load carrying component, has great advantages as both materials have unique characteristics. This paper is extended to study the effectiveness of the proposed strengthening system. The experimental program consisted of three phases. The first phase was designed to determine the optimum W/G ratio to be used for the mix design of Grancrete matrix using cubes subjected to pure compression stresses. The second phase was designed to evaluate the bond strength of Grancrete reinforced with different FRP materials including Basalt Grid Sheets, Steel Reinforced Polymers, and Carbon Strands. The third phase focused on applications of various FRG systems for flexural members. A total of 32 T-section beams were constructed and tested at the Structural Laboratory at Ain Shams University. This paper presents an in-depth study aimed at the development of a better understanding of debonding failures in RC beams strengthened with externally bonded FRP systems. Different analytical models are compared to test results. Test results also demonstrated that using U-Wraps eliminate debonding of the strengthening system and most likely failure occurs due to rupture of the FRP. The study was extended to predict the flexural behavior of the strengthened specimens. © APFIS 2015. All rights reserved.