Free Online Education Presentations

Honoring Michael M. Sprinkel - A Career of Concrete Preservation (ACI Spring 2024, New Orleans, LA) High Molecular Weight Methacrylate resins have seen increased use in a variety of applications. For sealing cracks in horizontal concrete substrates, the materials extremely low viscosity and extended gel time allows it to penetrate deep into cracks sealing them from water penetration. The development of handheld low pressure injection equipment makes it possible to seal cracks on horizontal as well as vertical concrete surfaces. Additional High Molecular Weight Methacrylate resin formulations with thixotropic properties makes it possible to seal cracks on vertical and overhead surfaces. The presentation will discuss the different application methods, equipment, and material physical properties.

Research in Progress (ACI Spring 2024, New Orleans, LA) Fiber-Reinforced Polymer (FRP) materials represent a promising alternative to traditional steel reinforcement in reinforced concrete (RC) structures. While FRP bars exhibit perfect elasticity, their inability to be bent post-production requires careful consideration of manufacturing-induced bends. This study focuses on the often-overlooked impact of stirrup bends, specifically those made of carbon fibers (CFRP), when used as transverse reinforcement. Current industry practices often report the strength of CFRP stirrups based solely on their straight portions, disregarding the influence of the stirrup bend. This research addresses this gap by presenting the findings of 40 experimental tests conducted on 20x20 in. CFRP spiral bends, conforming to ASTM D7914. These results are then compared with direct tensile tests conducted on the straight portions, adhering to ASTM D7205. Preliminary data indicates that the strength of the bend can be as low as 30% of the straight portion, emphasizing the importance of considering this factor in the design process.