Comparative study on fatigue behavior between unbonded prestressed and ordinary reinforced reactive powder concrete beams

Two types of reactive powder concrete beams, one with normal mild steel and another with unbonded prestressing tendons, were studied experimentally. Specifically, static load and constant amplitude fatigue tests were performed. The beam cracks, midspan deflections, and variations of extreme concrete and steel strains with fatigue loading cycles were compared. The fatigue test results show that fatigue life is more than 2 million cycles for both types of RPC beams within the usual low fatigue stress range (98 % probability of appearance). The crack width, maximum compressive strain, midspan deflection, and maximum tensile strain are 0.08 mm, 814 µ?, 7.6 mm, and 484 µ?, respectively for unbonded prestressed reactive powder concrete beams. They are 0.12 mm, 1147 µ?, 10.3 mm, and 1226 µ?, respectively for ordinary reinforced reactive powder concrete beams. All of these values obtained from the fatigue test are significantly below the corresponding failure values under the static test. The study results show that an unbonded prestressed reactive powder concrete beam has better fatigue performance than an ordinary reinforced reactive powder concrete beam.