The Optimization For Proportioning Of High Volume Fly Ash Hydraulic Dam Concrete And Performance Study

For a long time due to technical and conceptual obstacles,fly ash content was restricted in Fly ash concrete.Now normal dam concrete design ideas,fixing its many parameters remain unchanged,including water-cement ratio(water/cement ratio),unit water consumption,etc.As a reference,simply replacing cement with an equal amount of fly ash,preparation and mixing into concrete mixture of similar slump in laboratory,curing under normal temperature and humidity to test after a certain age,compared with reference concrete,determine the raw material and mixing ratio.That is the reason why most of the norms and standards limit the fly ash content.With the popularization of high performance concrete,a large number of successful engineering examples at home and abroad told us that high volume of fly-ash has a broad application prospect under low water cement ratio.The mass(dam)concrete mix design mainly according to the concrete workability、hydration temperature rise and durability,not the strength.The normal dam concrete which have good workability、durability and low heat of hydration can be really strong and durable.In this paper,the main work are as follows:One,based on three dimensional models of Dustan,using slurry volume method to make high volume fly ash dam concrete,Basic idea:making benchmark concrete mixture ratio which has been adjusted according to the experimental discipline,keeping the benchmark concrete volume of water and cement unchanged,mixed with fly ash as well as reducing water consumption.Two,on the basis of the aforementioned,using slump、weibo consistency and vibration viscosity coefficient etc methods to test the workability of high volume fly ash hydraulic dam concrete under the condition of different dosage,water-binder ratio,fly ash quality and grading of aggregate,and then determine the workability differences of change law under static and dynamic.Three,studying on the early age strength of high volume fly ash dam concrete under the condition of different dosage,water-binder ratio,fly ash quality and grading of aggregate,and then determining main factors affecting strength of high volume fly ash dam concrete.Four,testing high content fly ash dam concrete hydration heat of 1-7 days,comparing the change law of hydration heat under the condition of different dosage,Believe that mixed with a certain amount of fly ash in mass concrete is the effective measures to reduce the hydration heat and to avoid temperature cracks.