CONCRETE CONFINED WITH FIBER REINFORCED CEMENT BASED THIN SHEET COMPOSITES

摘要

In this paper, a new type of fiber reinforced cement-based thin sheet composite will be presented. This innovative technology can be applied to retrofit deficient concrete structures with a superior performance to current Fiber Reinforced Polymer resin (FRP) thin sheets. It is well known that significant improvements in compressive, shear, and flexural behavior of concrete can be achieved with externally bonded FRP sheets. In an effective retrofit with external FRP sheets, a layer of dry fiber sheet (usually unidirectional tape) is placed on the top of a coat of polymer resin that will harden to bond the fiber sheet to the concrete structure. However, composite action suggests that the individual parts of a composite must work together as one. Stresses must be transferred from the FRP sheet to concrete substrate through the interface. Such good bonding requires extensive concrete surface preparation before installation of FRP sheet. Concrete surface preparation is expensive and sometimes prohibited due to dust or noise concerns. Instead of using polymeric resins, the authors have been developing innovative cement-based matrix materials for making thin composite sheets. Cement-based materials have many advantages in comparison to polymeric resins. For instance, much less or no surface preparation is needed for good bonding. Additional benefits include much higher fire and vandalism resistance, and user friendly to the construction industry. Preliminary test data suggest that the effect of using the newly developed cement sheets on concrete confinement is similar to that of using conventional FRP sheets.