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      • Open Access Article

        1 - One-pot synthesis of Ag/Fe3O4 nanocomposite: Preparation, characterization and efficient catalyst
        Babak Sadeghi
      • Open Access Article

        2 - Biogenic Synthesis of Silver Nanoparticles Using Fruit Aqueous Extract of Psidium Guajava and Its Antibacterial Activity
        Babak Sadeghi Bita Koupaei
      • Open Access Article

        3 - Experimental study of modulus of elasticity of Alkali-activated concrete based on XRF and SEM tests
        Mohammadhossein Mansourghanaei Morteza Biklaryan Alireza Mardookhpour
        In this research, firstly, three mix designs of alkali-activated concrete containing 92, 96, and 100% blast furnace slag and 8, 4, and 0% nano-silica were made. After performing the compressive strength and modulus of elasticity tests and choosing one design as the opti More
        In this research, firstly, three mix designs of alkali-activated concrete containing 92, 96, and 100% blast furnace slag and 8, 4, and 0% nano-silica were made. After performing the compressive strength and modulus of elasticity tests and choosing one design as the optimal design in terms of superior mechanical properties, by adding 1 and 2% polyolefin fibers to the optimal design, two more designs of alkali-activated concrete were made. All concrete samples were subjected to compressive strength and modulus of elasticity, XRF and SEM tests. The results of the tests exhibited superiority in mechanical and microstructural properties of the alkali-activated concrete compared to normal concrete at all processing ages. At the processing age of 90 days (as the best age in performance due to the progress of the chemical process), following the compressive strength test, the lowest (49.94 MPa) and the highest (66.36 MPa) compressive strength values ​​were obtained, respectively, for design 1 including Normal concrete and design 4 including alkai-activated concrete containing 8% nanosilica. At the same processing age, the lowest (32.44 GPa) and the highest (42.51 GPa) modulus of elasticity were achieved in design 1 and 6 of the alkali-activated concrete containing 8% nano-silica and 2% polyolefin fibers, respectively. At this age, addition of 8% nano-silica and 2% fibers in the alkali-activated concrete of design 6 resulted in a decrease of 22.49% in the compressive strength and an improvement of 7.05% in the modulus of elasticity. Manuscript profile
      • Open Access Article

        4 - Experimental Study of Compressive Strength of Geopolymer Concrete Based on XRF and SEM Analysis
        Mohammadhossein Mansourghanaei Morteza Biklaryan Alireza Mardookhpour
        In this research, three mixing designs were made of geopolymer concrete containing 92, 96 and 100% composite blast-furnace slag including 8, 4 and 0% nanosilica, respectively. After performing the compressive strength test and selecting one of these three designs a More
        In this research, three mixing designs were made of geopolymer concrete containing 92, 96 and 100% composite blast-furnace slag including 8, 4 and 0% nanosilica, respectively. After performing the compressive strength test and selecting one of these three designs as the optimal design in terms of superior mechanical properties, by adding 1 and 2% of polyolefin fibers to the optimal design, two more designs were made of geopolymer concrete. Concrete specimens were subjected to compressive strength tests (at 7, 28 and 90 days of curing), XRF (at 7 days of curing), and SEM (at 90 days of curing). The results were evaluated and compared with the results of a mixing design made of ordinary concrete containing Portland cement. The results of the analyses in this research exhibited the superiority in mechanical and microstructural properties of the geopolymer concrete in comparison with the ordinary concrete at all ages. At the 90-day curing age, as the best age in terms of performance, the minimum (62.43 MPa) and maximum (82.96 MPa) compressive strength values ​​were obtained in designs 1 and 4, respectively. At this age, adding up to 8% nanosilica in geopolymer concrete enhanced the compressive strength up to 21.94% and adding up to 2% of fibers reduced the compressive strength up to 22.49% in this type of concrete. The results of XRF and SEM analyses overlapped with each other and were in accordance with the results of the compressive strength test. Manuscript profile
      • Open Access Article

        5 - Experimental Study of Engineering Specifications of Concrete Containing Local Mineral Pozzolan based on XRD and SEM Analyses
        Mojtaba Rangrazian Rahmat Madandoust Reza Mahjoub Mehdi Raftari
        Global warming and its effects on the environment can be considered as the important crises facing humans. Finding a method to reduce cement consumption can be an effective step in controlling the annual increase in global temperature. In this research, in order to find More
        Global warming and its effects on the environment can be considered as the important crises facing humans. Finding a method to reduce cement consumption can be an effective step in controlling the annual increase in global temperature. In this research, in order to find the optimal mixing design for replacing local mineral pozzolan instead of a part of cement, two mixing projects with four types of 5, 10, 15 and 20 percent by weight replaced a part of concrete cement.The compressive strength and concrete quality tests were evaluated in the specimens. The constituent elements of concrete and the effect of adding local mineral pozzolan were investigated using the XRD analysis, as well as the morphology and microstructural behavior of concrete with the SEM test. The results exhibited that the best replacement value of cement by pozzolan in concrete is equivalent to 15 percent by weight of cement. Pozzolanic samples increase the strength by 24% compared to plain cement concrete (PCC) samples. Optimal pozzolanic reaction reduced the amount of portlandite and calcite in concrete. Also, this pozzolan reduced the pores, increased the improvement and integrity of the interfacial transition zone (ITZ) in concrete in comparison with plain cement concrete. Considering the effects of this pozzolan on strengthening the structure and reducing the consumption of cement in concrete, the studied local mineral pozzolan can be introduced as a green material that reduces cement by increasing the strength of concrete and is environmentally friendly. Manuscript profile