Papers by Keyword: Reactive Powder Concrete (RPC)

Abstract: In order to study the mechanical performance of Reactive Powder Concrete (RPC) used for structure engineering, 38 series of RPC specimens are fabricated, cured, tested and analyzed. There are 5 sets of specimens are fabricated for each actual site structure engineering. The compressive strength, flexural strength and elastic modulus are tested according to the specimens and the compressive strength is tested with different age time. All the specimens are steam cured with the same situation as the structure. According to the test result, the compressive strength of RPC is up to 80MPa 3days after it is cast and the compressive strength is higher than 120MPa 15days later. The average flexural strength of RPC is 19.4MPa and the elastic modulus is 45.15GPa. The tested results show that the mechanical performance of RPC can satisfy the engineering requirement. The mixing proportion and the curing system can be used for engineering design and construction.

Abstract: The effects of ground limestone powder on the fluidity, strength and viscosity of reactive powder concrete(RPC) were studied. The results show that, the flexural strength of RPC greatly increases with the increase of the content of ground limestone powder at the W/B of 0.16, 0.18 and 0.20 when ground limestone powder content is less than 30%; for fresh RPC, the maximum compressive strength is 160MPa and the maximum flexural strength is 36.9MPa when the limestone powder content is 158kg/m3 at the W/B of 0.20, with 20cm good fluidity and very compact microstructure; the viscosity of RPC greatly decreases with the addition amount of ground limestone powder, the viscosity of RPC mixture changes from 60,000MPa•S to 18,000MPa•S when cement content decreases from 388kg/m3 to 150kg/m3 and the addition amount of limestone powder increases from 0 to 238kg/m3.

Abstract: By means of the three-point bending impact equipment, with the measurement of ultrasonic velocity, the impact behavior and damage evolution of reactive powder concrete (RPC) with 0, 1%, 2% and 3% volume fraction of steel fiber were tested. The results showed that steel fiber significantly improved the compressive strength, flexural strength, flexural toughness and impact toughness of RPC matrix. The compressive strength, flexural strength, flexural toughness of RPC with 3% steel fiber increased by 40.1%, 102.1%, and 37.4 times than that of plain concrete, respectively, and simultaneously, the impact toughness of RPC with 3% steel fiber was 93.2 times higher than that with 1% steel fiber. RPC with 2% and 3% steel fiber dosage both had relatively high compressive strength, flexural strength and flexural toughness; however, compared with the sample with 2% steel fiber dosage, the impact toughness of RPC with 3% steel fiber dosage increased by more than 10 times. Therefore, taking economy and applicability into consideration, if we mainly emphasis on the compressive strength, flexural strength and flexural toughness, RPC with 2% steel fiber is optimal. While if impact toughness is critical, RPC with 3% steel fiber would be the best choice.

Abstract: Reactive Powder Concrete (RPC) is a new kind of building material with high strength and other good performance. The combination of RPC and steel tube will compensate the brittleness of RPC and enhance the stability of steel tube, and the loading capacity of the RPC filled steel tube will be improved. Five RPC filled steel tube columns are designed and tested to obtain the ultimate load bearing capacity, the deformation and the strain information. During the loading process, the concrete and the steel tube of the RPC filled steel tube columns are loaded simultaneously. The loading results show that the deformation of the RPC filled steel tube columns are mainly in elastic phase before the loading capacity is up to the ultimate value. The test load decreases to be 80%~90% of the ultimate loading value and then it changes to be smooth. The failure mode of the RPC filled steel tube columns is ductile. The test loading capacity is compared with the formula from the reference. The tested ultimate load bearing capacity of the steam cured RPC filled steel tube columns is higher than the calculated value. The calculated value is safe for the engineering application. The study is useful for the research and application of RPC filled steel tube column.

Abstract: Two hollow rectangular bridge columns with Reactive powder concrete (RPC) were tested under a cyclically reversed horizontal load. Based on the test results, the seismic behavior of such columns was presented. An analytical model was developed to predict the force-displacement relationship of specimens. The test results were also compared to the proposed analytical model. It was found that the ductility factors of the specimens are over 4.0, and the proposed analytical model can predict the force-displacement relationship of such columns with acceptable accuracy.

Abstract: Reactive powder concrete (RPC) is a new kind of material with very high mechanical behavior and durability, however, high cost and complex procedure to make RPC result in hardly apply to engineering in large scale. a new low-cost RPC that compressive strength exceeds 130MPa was prepared with the replacement of quartz sand, crushed quartz and partial of silica fume by fly ash, slag and natural fine aggregate in the paper. Manhole cover that made from the low-cost RPC can meets the requirements of different situations, such as special road, motorway, etc.

Abstract: According to the theory of dense packing of particle, the theoretical particle size distribution of raw materials of RPC (Reactive Powder Concrete) was calculated. On the basis, the ratio of raw materials with different range of particle sizes of the RPC was determined by mechanical experiments. According to the determined ratio, a new type RPC was prepared by using flying ash and slag to replace part of cements and quartz flour, respectively. The workability, mechanical properties of the new RPC with different mix proportion and its shrinkage, cured at the normal temperature and 60°C, respectively, were studied. The results show that when water-binder ratio is 0.23, fly ash replaces 30% cements, slag replaces 50% quartz flour and superfine steel fibers percentage in volume is 2%, the compressive and flexural strength of prepared RPC are 160.1MPa and 25.3MPa, respectively, and after 3days heat curing (60°C), the dry shrinkage of it in 28days age reaches 299um/m. In addition, the fluidity of the new RPC is 258mm and meets requirements of workability of the pump concrete.

Abstract: In this paper, a series of Reactive powder concrete (RPC) footwalk braces without conventional steel bars are designed for the Qing-Zang railway. Experimental studies on the braces are conducted in order to test the mechanical character of the braces. Totally eight RPC footwalk braces are experimentally measured with static load. According to the analysis of the experimental results, the ratio of the crack load got from the experiment to the design load is 2.54 and the deflection ductile coefficient is 2.32. The experimental results show that the mechanical performance of RPC footwalk braces can satisfy the engineering requirements and there is enough safety margin for footwalk braces. A three-dimensional finite element analysis (FEA) is also carried out and the results of FEA are compared with that of the experiments. The results show that the FEA method can be used in designing the RPC footwalk braces.

Abstract: Reactive powder concrete (RPC), which is a new cement-based composite material with ultra-high strength, low-brittleness, excellent durability, is adopted to make well covers. In addition, static loading tests of the well covers are carried out. The test results show that the loading capacity of the RPC well covers can meet the requirements for different situations, such as the special roads, the city motorway, footway, various parking places, etc.

Abstract: Reactive powder concrete (RPC) is a new kind of ultra-high strength and upper ductility concrete first developed in 1990’s in France. In this paper, the RPC mixture proportion is optimized and its mechanical properties, such as compressive strength, flexural strength, elastic modulus, and its durability, are tested and discussed. Based on the optimal mixture proportion, four simply supported plain RPC beams (without reinforcement bars) are made and tested. The mechanical properties of plain RPC beams, including section deformation, load-displacement relationship, failure forms, crack distribution, crack extension, and ultimate flexural capacity, are discussed. It is concluded that RPC is an excellent material with high strength and durability. Steel fiber is important both to control the crack extension and to enhance the ductility of RPC beams.