Title:
Creep and Fatigue of Polymer Concrete
Author(s):
Michael Hsu and David W. Fowler
Publication:
Symposium Paper
Volume:
89
Issue:
Appears on pages(s):
323-342
Keywords:
beams (supports); compressive strength; creep-properties;
creep tests; deflection; fatigue (materials); fatigue
tests; flexural strength; methyl methacrylate; polymer concrete;
stresses.
DOI:
10.14359/6256
Date:
12/1/1985
Abstract:
Polymer concrete (PC) 3-in. x V-in. (75-mm x 300-mm) cylinders were loaded in uniaxial compression stress-strength ratios of 0.3, 0.4 and 0.5 for one year to investigate creep behavior. The PC was made with methyl methacrylate (MMA). The results indicate that the creep in PC is approximately one to two times higher than that of portland cement concrete. However, the specific. creep for both is about the same. The creep in-creases with an increase in the stress-strength ratio; but no linear relationship exists between the two variables. More than 20 percent of the final creep took place within the first day, and nearly 50 percent during the first five days. The static strength of PC was not significantly affected by the long-term creep loading. The high creep strain and the low sustained strength of PC could be the two major obstacles in its structural application. Plain PC 6 x 6 x 36-in. (150-mm x 150.-mm x 900-mm) beams made with MMA were tested to evaluate the flexural fatigue strength of PC subjected to different stress levels and stress ranges. The flexural behavior during the test period was observed. Beams were tested as simply supported beams with a 30-in. (750-mm) span and symmetrically loaded at third points. Beams were cyclically loaded at a constant rate of five cycles per second up to two million cycles or failure of the beam. Similar to port-land cement concrete, the applied stress is the most important factor influencing the fatigue life of PC. As the applied stress increases, the fatigue life decreases. The effect of the range between the maximum and the minimum applied stress was also significant; the wider the stress range, the shorter the fatigue life. Although the PC beam failed in a sudden, brittle mode, an increase in deflection was always noticed as the fatigue life was approached. The test results indicate that PC beams are superior to portland cement concrete beams in fatigue strength.