Title: Use of Fracture Mechanics Parameters to Monitor Concrete Deterioration Due to Delayed Ettringite Formation

Author(s): L. Bergol, G. Di Pace, C. Rocco, S. Szteimberg, and L. Zitzer

Publication: Symposium Paper

Volume: 212

Issue:

Appears on pages(s): 181-196

Keywords: concrete; delayed ettringite formation; durability; fracture mechanics

DOI: 10.14359/12685

Date: 6/1/2003

Abstract:
Fracture mechanics parameters, mainly Fracture toughness K1c and Critical ef- fective crack extension (Aacc), may be used to monitor deterioration of concrete members subjected to sulfate attack, specially Delayed ettringite formation. Concrete beams containing cements with different contents of C3A, gypsum and granulated blast furnace slag were casted and submitted to Fu's accelerated curing method (1), to trigger delayed ettringite formation. Then all specimens were immersed in 23 +- 1 oC saturated lime water for a period of 3 and 6 months, measuring the changes experienced in both Fracture Toughness and Critical Effective Crack Extension, following the Bazant-RILEM recommended practice. Additional sets of beams were tested to monitor Longitudinal Resonance Frequency, Ultrasonic Pulse Velocity and Length Change. X-ray Diffraction and Scanning Electron Microsope studies were carried out to confirm the presence of Delayed Ettringite Formation. At the present paper a brief introduction of Fracture Mechanics applied to concrete is included and test results up to date are presented.