The application of nano-materials and technology in new building materials
Nano-powder such as nano-SiO2, nano-CaCO3 and nano-silicon powder not only can fill cement gaps, improve the fluidity of the concrete, more importantly, it can improve cement concrete and aggregate interface structure, make the concrete strength, resistance permeability and durability are improved.
Studies have reported that when nanomaterials dosage is 1 % to 3% of cement dosage, and after mix with other mixture in the high-speed mixer, the hardened cement strength of nano composite structural materials in cement 7d and 28d age was increased by about 50% than not add nano material, and toughness, durability, performance has been greatly improved. Scientists have studied the influence of silicon powder and nano-scale SiO2 on the cement pastes water demands. Studies show that when nanoscale SiO2 ash cement consumption reached 8 %, the water demand of cement paste was increasing doubling. Meanwhile, the study found that when compound added 8% water and 10% cement, nano-SiO2 spheres small particles filled between silicon powder, form a good particle size distribution structure with silicon powder. When both are added and nanoscale SiO2 is l% and silicon powder is 9%, the water demand has not doubled, it is show that the interaction between them is obvious.
The applications of nano metal powder in concrete, due to surface effects of nano-materials, increases the activity of nano-materials, make the nano metal powder has two special properties, one of which is the strength of nano metal powder, high hardness, and with the grain size decreases, its strength, hardness continues to improve, but also showed a very good plasticity and toughness; Second nano metal powder is a good absorber. Used the special properties of nano metal powders mentioned above, if incorporated it into the cement concrete can be made functional electromagnetic shielding concrete.
The application of nano metal oxides in the concrete, anatase TiO2 nanoparticles is an excellent photocatalyst, it has air purification, sterilization, deodorization, self-cleaning surfaces and other special features. Use nano-TiO2 with clean air characteristic to prepare photocatalytic concrete, in purifying vehicle exhaust emissions it occurs photocatalytic reaction, decomposed and removed the motor vehicle emissions of sulfur dioxide, nitrogen oxides and other harmful pollutant gases, play the role of purify air.
Use of nano-metal oxide material can conduct electromagnetic shielding, can also be used to prepare concrete intelligence, such as cement concrete. This concrete has a strong conductive properties, also has sensing effect. This smart cement concrete can be used for civil engineering structures, real-time and long-term monitoring, to facilitate monitoring of concrete structures cracking and destruction and damage assessment, detect vehicle weight and speed, etc., which on concrete performance testing is a revolution.
Polymers or inorganic nanocomposites in concrete applications, due to the excellent performance of polymer or inorganic nanocomposites, make about its theoretical and applied research in composite materials become hot spots, it is also possible to apply in the cement concrete. Use the polymer or inorganic nano-composite materials in cement concrete, not only can improve the concrete compressive, tensile and flexural strength, but also can improve its durability. Mixed with a certain amount of polymer or inorganic nanocomposites in concrete mixture, and make it uniformly dispersed in the concrete, use the conductivity of polymers or inorganic nanocomposites, test resistance changes, established the load resistor between model, which can predict the destruction of concrete structures.
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