905
4324.006
Ramakrishnan, V; T.W. Bremner and V.M. Malhotra
Special Publication 136
Paper
American Concrete Institute
1992
397-420
Y
This paper presents the results of an experimental investigation to determine the flexural fatigue strength of lightweight concretes made using expanded shale aggregates. Six mixtures were investigated in this study. A total of 120 prisms, (20 prisms, 76 x 102 x 406 mm, in size, for each mixture) were tested in flexural loading of 20 cycles per second (Hz). The prisms which survived two million cycles of fatigue loading were tested in static flexure to determine their residual strength (modulus of rupture).The static flexural strength (modulus of rupture) ranged from 3.04 to 4.91 MPa. The fatigue strength varied from 2.2 to 3.0 MPa. The endurance limit (the ratio of the fatigue strength to the modulus of rupture) ranged from 0.55 to 0.72. The wet specimens tested at earlier ages had higher strength values (both fatigue strength and modulus of rupture), whereas the endurance limit was higher for dry specimens tested at later ages. There was an increase in the residual static flexural strength for the prisms previously subjected to two million cycles of fatigue stress.