Nano SiO2 and Cement Mortar
Investigation Of Mechanical And Physical Properties Of Mortars Containing Silica Fume And Nano-Sio2
چکیده مقاله
It has been found that physical properties of concrete, particularly strength and permeability significantly depend on its pore structure. Ultra fine particles of nano- SiO2 fill the voids of CSH structure and provide more homogenous distribution of hydrated products. This effect of nano-SiO2 enhances the durability ocement composites as well as the strength. In this paper, influence of nano-SiO2 on different properties of cement mortar was investigated in comparison with silica fume (SF) as a well-known active pozzolan. Different amounts of nano-SiO2 (0,1%, 3%, 5%, 7%and 9%) were incorporated into the ordinary cement mortar. Mechanical properties, shrinkage, water absorption of the specimens were determined. Results showed that the optimal content of Nano-SiO2 in plain cement mortar was around 7%. Nano-SiO2 particles were more effective in developing higher mechanical strength and lower water absorption than that of SF. Yet the mortar containing nano-SiO2 experienced higher shrinkage than that of SF mortar.
دریافت مقاله
Effect Of Polypropylene Fibers On Mechanical And Physical Properties Of Mortars Containing Nano-Sio2
چکیده مقاله
It has been demonstrated that the fiber-matrix bond strongly affects the ability of fibers to stabilize crack propagation in the matrix. As the bond between fiber and matrix is mainly mechanical, it seems that incorporating nano-SiO2 (NS) into fiber reinforced cement composites provides better bond with matrix through pore refinement and better distribution of the hydrated products. Hence in this paper an effort was made to study the effect of polypropylene (PP) fibers on mechanical properties and shrinkage of mortar incorporating NS. Three fiber volume fractions, 0.1%, 0.3% and 0.5% were considered. Compressive and flexural strength, water absorption and shrinkage of mortars were reported. Results showed that NS improved mechanical and water absorption characteristics of mortars significantly. It has been observed that the addition of NS fairly enhanced the fibers effectiveness in improving the mechanical strength of mortars.
دریافت مقاله
توضیح و منبع: هر دو مقاله در سومین کنفرانس بین المللی بتن و توسعه (تهران – اردیبهشت 1388) ارائه شده است
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