Study On Quality Inspection And Control Of Rockfill Concrete

In recent years, the concrete construction technology in our country has experienced a relatively rapid development stage, some new concrete dams with modern high-technology has been successfully applied in actual engineering, rock-filled concrete (RFC) is one of the typical example for the application. At present, the technology is one of the advanced and practical technology of the national Ministry of water resources.Rock-filled concrete technology is mainly developed on the basis of self compacting concrete, the formation of the stone concrete is mainly derived from the the performance of self-compacting ", It mainly makes use of self-compacting concrete with good fluidity, anti separation performance to fill the space in the stone heap, a large volume of concrete which can form a complete, higher density and low hydration heat without artificial vibration only relying on its gravity. However, The successful practice of the rock-filled concrete need to have a good technical personnel to provide strong technical support for the technical personnel, the relevant construction technical personnel need to master the construction methods and technical points, etc. Although the Ministry of water resources has issued the rock-filled concrete technical guidelines, which will make the rock-filled concrete construction become more standardization, but at this stage, RFC technology did not like ordinary concrete that is familiar to the public, the engineering quality control is still the focus of attention at the present stage.Based on the research of the new reservoir water—an Tang reservoir project, through the construction quality testing of concrete placement of RFC dam and pile, to explore some quality detection method of the RFC, and puts forward some efficient methods. According to the result of quality detection, making a research analysis on the rock-filled concrete material’s physical with the mathematical analysis method, focus on researching the internal mechanism and effect of the rock-filled rate and the stone particle size on density, strength and permeability. Under the conditions of this experiment, the main results and conclusions are as follows:(1) Though the core drilling on detecting the rock-filled concrete quality, with the effective quality control measures for construction quality testing. The results show that RFC concrete after hardening is dense, basically without quality defect.(2) The density of the RFC dam can be evaluated by the porosity. The test results show that, by measuring the surface porosity and bulk porosity of the concrete is preferably reflect the density of the RFC. In a certain range, with the rock-filled rate increases, the density of the RFC decreases and then increases. When the rock-filled rate is about 55%, the density is maximum.(3) The influence of rock-filled rate on the compressible strength and shear strength is similar to the law of the influence on the density under the condition of low water head. Rock-filled rate is 55%, concrete strength is the highest. The main factors that affect the concrete strength of the RFC is the rock-filled rate, while the stone particle size is less affected, but the size is 30-100cm which is beneficial to improve the strength of the concrete.(4) Because of the permeability of the concrete is mainly determined by the self-compacting concrete, there was no significant change in the permeability of the RFC with the rock-filled rate and diameter.(5) From test results of the core appearance show that, placing stone cleanliness directly affects bond degree between SCC and stone,otherwise it impacts strength of the dam, so the stone should deeply cleaning as far as possible before warehousing, to ensure the SCC and stone well bond. At the same time, in order to ensure the bonding strength between the inter-layer, we should do a good job in warehouse cleaning, so that it can meet the requirements of construction technology. There exits the best rock-filled rate, the rock-filled rate have a obvious effect on the dam density, compressive strength, shear index. So in order to ensure the construction quality, we should make strict control of the stone amount in the construction process before the warehousing.graduation of particle diameter...