Concrete, abbreviated as concrete, is a common material used in construction and widely used in civil engineering. Strength, durability, etc. are the indexes to measure the performance of concrete, and the admixture of microsilica is very good to improve the performance of concrete, and it is even widely used in the new RPC construction materials.
Silica Fume and RPC materials
Microsilica, also known as silica fume, or condensed silica fume, is a dust recovered from the flue gas of alloy smelting such as silicon metal or ferrosilicon. Since silica in microsilica powder is an amorphous substance with high activity, fine particles and large specific surface area, it has excellent physical and chemical properties, and its widely used in important fields such as concrete, refractory materials, wall materials, cement products, mortar, flooring and chemical industry used in special projects.
RPC is a high technology concrete material that combines the research ideas of DSP material and fiber reinforced material, with ultra-high strength, high toughness, high durability and high compactness. The raw material composition of this material is cement, micro silica powder.
HPC is the abbreviation of ultra-high performance concrete. Ultra-high performance concrete contains two aspects ‘ultra-high’, i.e. ultra-high durability and ultra-high mechanical properties. Its appearance to achieve a great leap in the performance of engineering materials. But the emergence of RPC materials greatly surpasses the performance advantages of HPC.
RPC and HPC
The durability of RPC materials and HPC are compared and analyzed through the chloride ion penetration test, freeze-thaw test and carbonization test, and the durability mechanism is analyzed as follows in combination with microscopic tests.
1.Permeation resistance
The results of chloride ion diffusion coefficient and permeability classification and evaluation of RPC and HPC measured by NEL method show that the permeability grade of RPC material reaches V according to the standard CCES01:2004, and the evaluation result of permeability permeability is “very low”, that is, the permeability resistance of RPC is very high, and the permeability grade of HPC reaches III. The permeability grade of HPC reaches Ⅲ, and the evaluation result of permeability penetration performance is “medium”. This shows that the permeability resistance of RPC is much higher than that of HPC material.
2.Frost resistance
RPC has no mass loss after 300 cycles of freezing and thawing, and its dynamic mode loss is only 0.8%, and its durability index is nearly 100%. HPC has a mass loss of more than 5% after 250 cycles of freezing and thawing, and its dynamic mode loss is 36.4%, and its durability index is only 47.8%. This shows that the RPC material has excellent anti-freezing performance and the resistance to freeze-thaw cycles is much higher than the HPC material mixed with silica fume. It meets the requirements of the standard CECS01:2004 on the frost resistance of concrete materials working in harsh environments.
3.Permeability resistance
RPC material has excellent resistance to permeability, the diffusion coefficient of chloride ion is only 22.17×10 m2/s, and the permeability grade reaches V level. The dense particle grading design and high temperature active excitation significantly improve the pore structure inside the matrix and the density of the interface in the transition zone, effectively improving the resistance to permeability.
4.Freeze-thaw damage resistance
RPC has excellent resistance to freeze-thaw damage, and the durability index of freeze-thaw cycle is nearly 100%, which is suitable for the structure working under the environment of salt or chemical corrosion and freeze-thaw cycle in the cold region. the high compactness of RPC material and the reinforcing and toughening effect of steel fiber effectively improve the resistance to freezing. the high compactness of RPC material and the uniform distribution of non-crystalline Ca(OH) generated under the condition of high temperature and hot and humid maintenance in the C-S-H gel, which effectively improves the carbonation resistance of concrete.
Application of silica fume RPC
- RPC concrete in railroad bridges, nuclear power plant projects can be used, such as China’s Qinghai-Tibet Railway bridge, France’s Cattenom nuclear power plant, the use of RPC concrete.
- RPC concrete manufactured cable channel cover and other components not only has high strength, high durability, and light weight, easy construction and installation, with easy to shape, beautiful appearance, long-term benefits and other characteristics.
- RPC is used in a large number of sidewalk covers. In recent years, RPC covers have entered the common design drawings of the Ministry of Railways. Nowadays, RPC prefabricated covers have been applied in municipal roads, Beijing-Shanghai high speed, Harbin-Dalian passenger special line, Ning-Shanghai inter-city railroad and other projects.
Significance of new building materials
Compared with traditional building materials, the application of new building materials makes it stronger, lighter, energy-saving, more powerful and more in line with the development requirements of our country. In terms of relevant performance research, new building materials have been greatly improved in terms of mechanical properties, durability and corrosion resistance. In the production process, the production raw materials are fully utilized, and new technology and new techniques are adopted to improve the performance of the materials.
Henan Superior Abrasives specializes in the production of high quality microsilica for various applications. We supply silica fume for RPC, refractory materials, construction and other materials, welcome new and old customers to consult and visit us. We will be happy to serve you.
