000004602 001__ 4602
000004602 005__ 20141119144537.0
000004602 04107 $$aeng
000004602 046__ $$k2002-06-02
000004602 100__ $$aChariton, Todd
000004602 24500 $$aUSING PASSIVE ACOUSTIC ENERGY TO QUANTIF Y CRACKING IN VOLUMETRICALLY RESTRAINED CEMENTITOUS SYSTEMS

000004602 24630 $$n15.$$pProceedings of the 15th ASCE Engineering Mechanics Division Conference
000004602 260__ $$bColumbia University in the City of New York
000004602 506__ $$arestricted
000004602 520__ $$2eng$$aExperiments were conducted using restrained and unrestrained linear ‘bar-type’ specimens. Acoustic sensors placed on the restrained specimens show a high degree of activity during the first several days that is presumably due to the development of distributed damage (micro-cracking). This can be attributed to surface cracking that occurs as a result of moisture gradients that cause the surface concrete to shrink much more rapidly than the core concrete. After the first few days however a discrete increase in acoustic activity is typically observed in the restrained specimens that was followed by the development of a visible crack. To better understand differences in the behavior of the unrestrained and restrained specimens, additional parameters of the general acoustic wave are analyzed. As the concrete nears the age of visible cracking the acoustic waves generated in the restrained specimen increase in duration and amplitude. The rate of energy dissipated in the unrestrained and restrained specimens is typically observed to deviate prior to the development of visible surface cracking signifying the onset of crack initiation and growth. Current research is aimed at relating the deviation between the acoustic energies of different specimens with changes in mechanical properties such as fracture energy or stiffness reduction.

000004602 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000004602 653__ $$aAcoustic Emission, Cracking, Fracture, Moisture Gradient, Restraint, Shrinkage

000004602 7112_ $$a15th ASCE Engineering Mechanics Division Conference$$cNew York (US)$$d2002-06-02 / 2002-06-05$$gEM2002
000004602 720__ $$aChariton, Todd$$iKim, Byounggeon$$iWeiss, W. Jason
000004602 8560_ $$ffischerc@itam.cas.cz
000004602 8564_ $$s42092$$uhttp://invenio.itam.cas.cz/record/4602/files/033.pdf$$yOriginal version of the author's contribution as presented on CD, .
000004602 962__ $$r4594
000004602 980__ $$aPAPER