Interface shear transfer of lightweight-aggregate concretes cast at different times

摘要

>This study examined the direct shear transfer across an interface of lightweight aggregate concretes cast at different times. Increasing use of lightweight aggregate concretes prompted this investigation to determine the appropriateness of current shear friction design provisions with respect to all-lightweight and sand-lightweight concrete. The experimental investigation included 36 push-off specimens? constructed with a cold joint along the shear plane. Test variables included concrete type (unit weight), compressive strength of concrete, and surface preparation of the shear interface. A constant amount? f reinforcing steel (1.33%) was provided across the shear plane. Applied? shear force–slip relations were presented and discussed. Peak and residual shear strengths were also compared. Results? suggest that concrete type did not play a significant role in the shear strength of the specimens in this study. Shear strengths computed using the shear friction design provisions in the Building Code?? Requirements for Structural Concrete (ACI 318-11) and Commentary (ACI 318R- 11) and PCI Design Handbook: Precast and Prestressed Concrete were conservative for the sand-lightweight and?? all-lightweight specimens.