Title: Deformation and Failure in Large-Scale Pullout Tests

Author(s): William C. Stone and Nicholas J. Carino

Publication: Journal Proceedings

Volume: 80

Issue: 6

Appears on pages(s): 501-513

Keywords: aggregate interlock; compressive strength; cracking (fracturing);crack propagation; deformation: failure mechanisms; models; pullout tests; reinforced concrete; strain gages.

DOI: 10.14359/10871

Date: 11/1/1983

Abstract:
An experimental studv was performed to gain an understanding of the failure mechanism of the pullout test for concrete materials. Two large-scale pullout inserts were fabricated and embedded in large concrete blocks. Micro-embed-ment strain gages were placed in the concrere to measure the internal strain distribution in critical regions. Insert disk displacements were also measured along the line of load application. Based on the discontinuities in the load-strain histories for the embedded gages, a failure mechanism is hypothesized. Failure is thought to begin at the disk edge at about one-third of ultimate load. Circumferential cracking propagates from the disk to the reaction ring with increasing load. At about two-thirds of ultimate, circumferential cracking is completed, and the load is thought to be carried via aggregate interlock across the fracture surface. Ultimate failure is probably due to pullout from rhe matrix of the bridging aggregate particles. In contrast to previous theories the measured compressive strains were too low to cause compressive failure of the concrete.