Application of Aluminum Oxide Powder in Concrete

Cement concrete has been one of the important structural materials in construction since its introduction, and the research on nano concrete has made many achievements and has been widely used. With the continuous expansion of the scale and use of concrete structures, its use environment and load are becoming more and more complex. Concrete structures inevitably face the threat of extreme external loads such as impact, high temperature, and explosion during use, so nano alumina plays an important role in concrete. Therefore, in order to ensure the safety and reliability of concrete structures, it is necessary to modify the properties of concrete further to meet the requirements for use under various conditions.

Role of Aluminum Oxide Nanoparticles in Concrete

The particle size and morphology of ultrafine nano alumina powders have a great influence on their physical and chemical properties, and their morphology essentially determines the overall and surface properties of the powders. In addition, the structural and morphological characteristics of the powder include the shape, chemical composition, material composition, internal and external surface area, volume, and surface defects of the powder, which together determine the overall performance of the ultrafine nano-powder.

The appearance of nano-alumina concrete is more homogeneous than that of ordinary concrete, with fewer pore shadows, no obvious weak areas and reticular or columnar crystal cross sections, and no needle-like harmful crystals and a large number of clustered crystals. Under a high magnification scanning electron microscope, prominent round granular crystals can be seen, which are not clearly separated from the matrix, with few impurity crystals, a uniform cross-section, and a dense micro-morphology. The prominent granular crystals increase the contact area and contact friction of the reaction, which, to some extent, prevents relative sliding within the structure when the structure is destroyed. Meanwhile, the large specific surface area of nano-alumina has strong adsorption capacity and catalytic activity. Calcium hydroxide produced during cement hydration can form calcium aluminate hydrate on the surface of nano alumina, which can easily combine with the total hydration products of cement. In this process, a large number of harmful hexagonal flaky calcium hydroxide crystals are consumed by the reaction. In addition, the nano-alumina is dispersed in the cementitious composite and fills in the micropores of the cement paste. On the basis of the original reticular structure of the cement hardening paste, more nanoscale hydration products are combined to form a new dense network structure, which refines the harmful calcium hydroxide crystals in the interfacial transition zone, improves the enriched and oriented arrangement performance of the calcium hydroxide crystals in the transitionally weak zone of the concrete micro-interfacial zone, increases the content of the hydration products in the interfacial weak zone, optimizes the interfacial properties of the matrix, and improves the denseness of the cement hardening paste.

Nano-alumina is a new type of nanomaterial with surface effect, small size effect, and macroscopic quantum tunneling effect. Its optical, thermal, electrical, magnetic, mechanical, and chemical properties are advantageous. Adding nano alumina has natural compatibility with cement; nano alumina has very high strength and good toughness. Its products have high activity in the hydration reaction of cement, which can effectively improve the performance of concrete. Some experiments have shown that nano alumina is uniformly dispersed in concrete and changes the concrete interior from the microscopic level, thus affecting the macroscopic mechanical properties.

Supplier of Concrete Admixtures

TRUNNANO is a supplier of Concrete Admixtures over 12 years experience in nano-building energy conservation and nanotechnology development. It accepts payment via Credit Card, T/T, West Union and Paypal. Trunnano will ship the goods to customers overseas through FedEx, DHL, by air, or by sea. If you are looking for high quality Concrete Admixtures, please feel free to contact us and send an inquiry. (sales@cabr-concrete.com).