Ordinary concrete presents short service life when used for building and repairing high-grade road with heavy traffic due to its large brittleness, poor bending flexibility and serious shrinkage on drying. In this pap...Ordinary concrete presents short service life when used for building and repairing high-grade road with heavy traffic due to its large brittleness, poor bending flexibility and serious shrinkage on drying. In this paper, a new kind of high performance concrete has been designed by means of combination of organic, inorganic material as well as metal material. The research and application have shown that this new concrete can significantly counteract the deficiency of ordinary concrete and give excellent mechanical properties and pavement performances. The application of this new kind of concrete is of great social and economic significance.展开更多
Perhydropolysilazane,a low viscosity preceramic polymer with good wettability and high char yield,was used to fabricate three-dimensional silica fiber reinforced silicon nitride matrix composites through the repeated ...Perhydropolysilazane,a low viscosity preceramic polymer with good wettability and high char yield,was used to fabricate three-dimensional silica fiber reinforced silicon nitride matrix composites through the repeated infiltration-curing-pyrolysis cycles.With the increase of the pyrolysis temperature from T_(1),T_(2)to T_(3),the density of the composites increased all through,but the flexural strength showed a maximum value at T_(2)followed by a sharp decrease.The composite prepared at T_(2)exhibited a good ceramization of the preceramic polymer,a high flexural strength of 144.9 MPa and excellent dielectric property.The high performance of the composite resulted from the good state of the silica fibers,controlled fiber/matrix interfacial microstructures and high-purity dense silicon nitride matrix.展开更多
文摘Ordinary concrete presents short service life when used for building and repairing high-grade road with heavy traffic due to its large brittleness, poor bending flexibility and serious shrinkage on drying. In this paper, a new kind of high performance concrete has been designed by means of combination of organic, inorganic material as well as metal material. The research and application have shown that this new concrete can significantly counteract the deficiency of ordinary concrete and give excellent mechanical properties and pavement performances. The application of this new kind of concrete is of great social and economic significance.
文摘Perhydropolysilazane,a low viscosity preceramic polymer with good wettability and high char yield,was used to fabricate three-dimensional silica fiber reinforced silicon nitride matrix composites through the repeated infiltration-curing-pyrolysis cycles.With the increase of the pyrolysis temperature from T_(1),T_(2)to T_(3),the density of the composites increased all through,but the flexural strength showed a maximum value at T_(2)followed by a sharp decrease.The composite prepared at T_(2)exhibited a good ceramization of the preceramic polymer,a high flexural strength of 144.9 MPa and excellent dielectric property.The high performance of the composite resulted from the good state of the silica fibers,controlled fiber/matrix interfacial microstructures and high-purity dense silicon nitride matrix.
