Title: Field Application and Monitoring of Crack Resistant Fiber-Reinforced Concrete Overlays

Author(s): R. Gupta, N. Banthia, and P. Dyer

Publication: Symposium Paper

Volume: 268

Issue:

Appears on pages(s): 123-138

Keywords: cracking; fiber-reinforced concrete (FRC); overlays; restrained plastic shrinkage; slab-on-grade; synthetic fiber.

DOI: 10.14359/51663713

Date: 3/1/2010

Abstract:
Water loss from concrete results in volumetric shrinkage, which is significant at early ages. This shrinkage is particularly pronounced when the surface to volume ratio is large of the placements. Fibers, especially synthetic fibers are known to reduce cracking induced due to restrained plastic shrinkage. However, few studies have been conducted to monitor the early-age shrinkage of fiber reinforced concrete (FRC) using embedded sensors in the field. This study involved developing crack resistant FRC material in the laboratory using the bonded overlay technique developed at UBC and using it for a field project. Results from a plain concrete slab-on-grade section and a high volume fly-ash placement were used for comparison with fiber-reinforced concrete (FRC). Three sections were cast using synthetic fiber and their performance was monitored by reading strain signals from embedded sensors. Both traditional (electrical) and state of the art optical sensors were used. Optical sensors registered low strain values due to lack of bond with concrete. On the contrary, traditional electrical sensors clearly demonstrated the reduction in strain in FRC when compared to plain and fly-ash concrete. Specimens were cast on site for conducting tests in the laboratory. In addition, nondestructive tests were conducted on-site for monitoring performance of the slabs. These results are also presented in this paper.