چكيده به لاتين
Despite the positive properties of concrete, which makes this material useful in the construction of marine structures and bridges, residential and commercial buildings, water transmission routes and roads, there are significant weaknesses such as producing significant amounts of carbon dioxide as one of the environmental pollutants as well as high energy and cost in the cement production process, porosity, high permeability and sensitivity to the presence of invasive ions in the environment may limit the use of concrete and similar materials in the coming years. With the development of the construction industry and the growing importance of sustainable development and the environment, and on the other hand, due to the weaknesses of concrete, concerns about increasing costs and reducing resources for cement production and recurrence of these problems have intensified and consequently Increased research to find a solution. Therefore, due to cement-like properties and the existence of sufficient sources of pozzolans as well as the significant properties of nanoscale materials, in this study, the effect of combined use of graphene oxide and natural zeolite on the properties of cement mortar samples was investigated. In this study, 10, 15 and 20 wt% of pozzolans were used as cement substitutes as well as 0.05% by weight of graphene oxide with water to cement ratio 0.485 were selected and then fluidity, compressive and flexural strength, porosity by gas porosimetry, ultrasonic pulse velocity, capillary water absorption, length and mass change of the sample in sulfate solution, rapid chloride migration test on cement mortar samples at the ages of 28 and 90 days were performed. According to the fluidity test results of fresh mortar, the use of zeolite and nano-graphene oxide, either alone or in combination with each other, caused the fluidity decline. The simultaneous presence of zeolite and graphene oxide also helped to reduce the water permeability, chloride and sulfate ions penetration by reducing the porosity of the sample, so that the sample containing graphene oxide and 20 wt% zeolites showed the best results in reducing the permeability. Also, the highest rate of capillary water absorption and chloride ion penetration was observed in the sample containing 0.05% of graphene oxide and the highest rate of expansion and mass changes were observed in the control sample. The flexural and compressive strength of the sample containing a combination of graphene oxide and 15% pozzolan increased by about 21 and 45% compared to the control sample with the highest strength compared to other designs, respectively. In general, it can be said that the best sample in the discussion of mechanical strength of the sample contained a combination of graphene oxide and 15% zeolite and in the discussion of the durability of the sample contained 20% of pozzolan in combination with 0.05% nanographene oxide.
