چكيده به لاتين
Concrete as a material consisting of two phases of aggregate and hydrated cement; in the third phase, which is the common phase of the two phases (affecting almost all the behavioral properties of concrete); can accept water and soluble aggressive materials in it (like chloride). The more this area is capable of absorbing water, the more vulnerable it is to natural aggressive factors such as carbonation, chlorine ion penetration, and corrosion of reinforced steel and melting and freezing cycles. The presence of water and soluble materials (such as chloride) in the vicinity of steel buried in concrete will gradually corrode the steel and eventually disintegrate the concrete and endanger the durability and health of the structure. These days there are many different ways to improve the reliability and durability of concrete. In this regard, in the present study, the three-dimensional protection of hydrophobic carbon powder and the effect of its addition to the mixture on the durability properties of concrete have been tested to evaluate its suitability for use as an additive in concrete from a reliability point of view. In this study, after reviewing past activities and the effects of adding carbon powder to concrete, a suitable mixing scheme was determined and finally the powder used as a different weight percent of cement replaced the same amount of sand mass. Then, the compressive strength of the specimens was tested at 7, 28 and 90 days of age, with the exception of samples having less than 10% by weight of cement. Then the properties of concrete durability were investigated through experiments: volume adsorption, capillary penetration, electrical resistivity, corrosion potential and chlorine penetration. Water permeability in the samples decreases with increasing amount of carbon powder. But other results indicate that there is an optimum percentage of powder for maximum durability. According to the results of the electrical resistance test and the chlorine profile, the samples with 10% by weight of carbon powder had 40% and 30% better performance than their control samples, respectively. Also, regarding the corrosion potential, all samples with carbon powder (except 20% carbon powder) performed better than their control sample, such that after 140 days immersion in 5% sodium chloride solution, While the sample containing 10% carbon powder is less than 10% likely to corrode, the control sample is more than 90% likely to corrode.
