Effects of different curing regimes on the mechanical behavior of reactive powder concrete

Abstract

Reactive powder concrete (RPC), which is defined as a superior type of concrete with fine and ultra-fine ingredients, is commonly used in special applications such as bridges, infrastructures, and machine foundations. Several types of high-temperature curing applications are used to increase the ultimate strength and accelerate the strength-gaining rate of RPC. In this study, different aspects of steam curing processes, such as longer pre-waiting periods, interrupting the curing process, and changing the curing duration were investigated to determine their effects on the mechanical behavior and water permeability of RPC samples. The samples were steam cured at 90 degrees C in some variable conditions such as continuous 120 h of steam curing, 2 days of interruption during 120 and 144 h of steam curing, and a 7-day prolonged pre-waiting period. The effects of 7, 28, and 180 days of water curing applications on the properties of RPC were examined, and the results were compared with steam-cured specimens. These curing processes were applied to the laboratory samples and the prefabricated infrastructure elements produced using the same batch of RPC at an industrial facility. The results showed that the interruption of the steam curing or longer pre-waiting period did not have significant effects on the compressive strength, splitting tensile strength, abrasion resistance, and water absorption of the tested RPC samples. Curing conditions were found to have a slight effect on the fracture energy results of RPCs. The longer steaming period, although interrupted for 2 days, increased the fracture energy of RPC. On the other hand, the fracture energy results of prolonged pre-waiting period samples that waited for 7 days before steam curing were found to be vaguely lower than those for the samples cured after a day. The load test results of the manhole cover produced with RPC showed that it is possible to reach the desired values with all tested curing conditions, although the retardation of the steaming period resulted in the lowest manhole cover fracture load and higher permanent set values.