Articles

Bonding of Overlays to Ultra High Performance Concrete

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Abstract

In Delaware, latex modified concrete (LMC), polyester polymer concrete (PPC), and modified concrete type D overlays are commonly applied over UHPC components as a riding surface. The bond performance of overlays adhered to UHPC is unknown and the current literature does not address this knowledge gap. Moreover, there is a need to verify the existing pull pull-off bond test method on overlays bonded to UHPC. Finally, existing surface texture metrology was developed for normal concrete substrates and is not necessarily applicable to UHPC. In this work, the sensitivity of bond pull-off test (ASTM C1583) parameters, such as coring depth and overlay age, was investigated to establish the most appropriate test conditions. The project evaluated the effects of UHPC surface preparation method (specifically, diamond grinding and sandblasting, hydrodemolition, and surface retarder) on the bond strength. In addition, surface roughness of UHPC was assessed via surface profile gauge, sandpatch method, and ICRI concrete surface profile (CSP) chips. The coring depth of 0.5 in. was adopted based on the sensitivity study results and practical considerations. The research found that PPC had the highest pull-off bond strength averaging at 730 psi (at 28 days), followed by LMC with an average of 450 psi and, finally, MCD which did not exceed the minimum recommended value of 250 psi. The pull-off bond strength did not vary significantly between the three surface preparation methods. It was concluded that surface profile gauge is the most appropriate method to quantitatively evaluate UHPC surface roughness, but it is not the most practical to implement.

Keywords: ridges, bond, overlays, surface preparation, latex modified concrete, polyester modified concrete

How to Cite:

Larfi, S. & Tatar, J., (2023) “Bonding of Overlays to Ultra High Performance Concrete”, International Interactive Symposium on Ultra-High Performance Concrete 3(1). doi: https://doi.org/10.21838/uhpc.16668

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