Behaviour of steel and synthetic fiber reinforced concrete under flexural creep loading.

摘要

The intent of this study was to characterize and compare the post-crack flexural creep of steel and synthetic Fiber Reinforced Concrete (FRC). Prior to this study, no information in the literature was available for the post-crack flexural creep performance of macro-fiber reinforced concrete. A novel and innovative flexural creep testing apparatus and procedure was developed independently due to the absence of a suitable standard or precedent in the literature.; Two different FRC mixtures were tested under flexural creep loading. The concrete mixtures were identical except for the type of fiber added. The first mixture contained a hooked-end steel fiber at a dosage of 24 kg/m 3 (0.3% by volume). The second mixture contained a coarse monofilament fibrillating synthetic fiber at a dosage of 4.6 kg/m3 (0.5% by volume). Beams were cast for each concrete mixture in accordance with applicable ASTM standards. The specimens were water cured to ensure full strength and tested, following ASTM C1399, to obtain the Average Residual Strength (ARS) of each FRC mixture. Pre-cracked beams were then statically loaded in third-point flexure at various percentages of the ARS for each mixture. The synthetic FRC beams were loaded at 20%, 40%, and 60% of ARS and the steel FRC beams were loaded at 20%, 40%, 60%, and 80% of ARS. Static loads were sustained indefinitely to allow creep of the specimens to occur. Center point displacements of the individual specimens, temperature, and humidity were monitored for the duration of the study. Test specimens were loaded for a minimum of 90 days. Testing was performed at room temperature and moderate relative humidity levels. (Abstract shortened by UMI.)