Title: Splice of Glass Fiber-Reinforced Polymer-Reinforced Concrete Mixed with Superabsorbent Polymer
Author(s): Yail J. Kim and Junhao Gao
Publication: Structural Journal
Appears on pages(s): 31-44
Keywords: fiber-reinforced polymer (FRP); internal curing; performance assessment; splice; superabsorbent polymer
This paper presents the effects of inadequate splicing between glass fiber-reinforced polymer (GFRP) bars on high-performance concrete mixed with an internal curing agent, superabsorbent polymer (SAP). The lapped splice length varies from 0.2ld to 1.0ld, where ld is the basic development length determined by a design guide, while the amount of SAP ranges from 0% to 0.4% of the cement mass conforming to published literature. Ancillary tests are conducted to evaluate the hydro-physical properties of SAP. Upon loading 15 slabs under four-point bending, the load-carrying capacity, flexural behavior, failure details, and crack development associated with the variable lap lengths are studied, including SAP-splice interactions. The capacity and failure locations of the slabs are primarily controlled by the splice length, whereas the amount of SAP affects the stress development of the reinforcing bars. The service behavior of the slabs with a splice length of 0.4ld to 1.0ld is analogous until a splitting crack takes place, which differs from the behavior of the slabs with 0.2ld showing premature splice slippage and reinforcing bar dislocations. As the splice length of the slab increases, the capacity tends to be insensitive to the presence of SAP. Factorial analysis substantiates that the implications of the SAP amount and splice length, and their mutual dependency, are statistically significant at a 5% confidence level. In accordance with analytical modeling, the interfacial stress between the concrete and GFRP reinforcement asymptotically decays with the splice length, and influences the crack-localization and concrete-spalling of the slabs. A characteristic angle is derived and proposed to quantify the integrity of the splice.