| In the1990s, a new type of high performance concrete came into being, which is called reactive powder concrete (RPC). The concrete is a new type of cement-based material with high strength and high durability. It is developed from researchers of Bouygues Company in France. Compared with ordinary concrete, the RPC’s strength and durability have been improved greatly. It is a high-quality concrete with excellent characteristics. The previous RPC uses steel fibers as a reinforcing material, which can result in high mechanical properties. When it is used in seawater or other aggressive environments, the steel fibers may be corroded. The durability and the appearance of the structure may be affected by the surface rust. In this thesis, a high quality fiber of basalt Fiber (BF) is admixed into the RPC and forms a new basalt fiber reinforced RPC. The mechanical properties and some durability indexes of the RPC are researched, and the reinforcing mechanism is analyzed theoretically.Based on large number of experiments, the mechanical properties and some durability indexes of RPC are researched. BFs with different aspect ratio are admixed in different content into RPC, and the change regulations are compared with each other. The experimental process and main achievements of this thesis are as follows:1. Taking the content of the aggregate, cementitious materials and wate-r-cement ratio as variables, comparing the compressive strength and the flexural strength of plain RPC, a relatively ideal mixture proportion is obtained by uniform design method, and the statistical analysis.2. Four types of BFs with different aspect ratios are admixed into RPC, whose contents are2kg/m3,3kg/m3,4kg/m3and5kg/m3, respectively. The compressive strength, flexural strength and splitting tensile strength are tested. The results indicate that as the content of the basalt fibers varies, the RPC’s mechanical properties vary in different trends, so as to the aspect ratio of BFs.3. Two types of basalt fibers with different aspect ratio are admixed into the RPC, whose dosages are2kg/m3,3kg/m3,4kg/m3and5kg/m3, respectively. The result of chloride penetration resistance shows that the RPC has better resistance to chloride ion penetration than the plain RPC. RPC’s chloride penetration resistance changes as the content and the aspect ratio of BFs change. Compared with the normal concrete, the RPC’s chloride penetration resistance is much higher. So the BFRPC and the plain RPC both have a high resistance to chloride penetration, especially mixed with the BFs.4. The impact toughness of BFRPC with different aspect ratio and different content of BFs is tested, and compared with RPC with the same content of steel fibers. The results indicate that the impact toughness changes with the variation of aspect ratio and content of BFs. The impact toughness of the RPC admixed with BFs is significantly improved. The RPC’s impact toughness is better than that of plain RPC. The impact toughness of steel fiber reinforced RPC is higher than that of BFRPC. As the content changes, the impact toughness generally enhances firstly and then decreases.5. The enhancing principle of the RPC mixed with fibers is analyzed theoretically. The enhancement mechanism could be explained by fiber spacing theory and composite material theory. The aspect ratio and the content of the fibers both influence its mechanical properties significantly.6. In the thesis, other organic fibers such as cellulose fibers, polythene fibers, polythene alcohol fibers and polypropylene fibers are admixed into the RPC, whose volume contents are correspondent with the basalt fibers. It shows that the compressive strength and flexural strength could not be increased obviously, and the RPC could not be reinforced. |
