Events > Tilt-Up Convention and Expo 2021 - St. Louis > SESSION

Why Glue Don’t Work

September 18, 2021 from 11:30am to 12:30pm Central Standard Time

Hyatt Regency 4th Floor - Grand F-H

Chad Bruce

Measuring the unintended impact of chemical curing agents, bond breakers, and densifiers on concrete surface free energy.

Tilt projects can be a series of conflicting goals. Maybe none more prevalent then the pursuit of a perfect concrete slab for casting beautiful panels and using adhesives to bond forming materials. Building owners want tight, densified concrete slabs and tilt-contractors want to get the project moving minimizing steps and slab curing times. So, as an industry we have turned to chemicals to get the job done. Densifiers are more prevalent and bond breakers are being used as curing compounds. Unfortunately, both of these solutions negatively impact the concrete’s surface free energy, in other words “it makes the glue not work.”

Over the last year, GluDown has been researching ways to accurately measure concrete slab surface free energy, identify potential challenges from these measurements, and provide corrective actions for glue down job success. We will present these findings to the TCA to open the industry’s eyes to this challenge, hopefully generate discussion on how to use this information, and ultimately create specifications which will better tilt-up forming practices.

LEARNING OBJECTIVES

• Using Young’s Equation, we can measure and quantify the Surface Free Energy of concrete slabs.
• Addition of chemical agents and/or the order they are applied to the concrete slab can negatively impact the success of adhesives on “No or Minimal Hole” specified concrete slabs. This failure can lead to drill holes which would be otherwise unnecessary.
• Analyzing Surface Free Energy measurements, we can project the success of using adhesives to form materials.
• No or minimal hole (glue down) jobs should have a specified concrete slab surface free energy target.