Research On The Secondary Interface Of The Superfine Sand Concrete

The application of superfine sand concrete in our country has a history of more than half a century. now the use scope is becoming more and more widely. We have a certain understanding of the superfine sand concrete. Superfine sand refers to the sand that the fineness modulus is between0.7and1.5, and the average particle size is under0.25mm. It has different grain size distribution, large void fraction (10%to20%larger than the coarse sand in), larger surface area (two times larger than that of medium and coarse sand), and higher silt content. When prepared with the superfine sand concrete, if preparation method or the later maintenance is not good enough, the strength of concrete will decrease and will appear cracks. So it’s necessary to study the superfine sand concrete fully, especially from the micro angle of the superfine sand concrete.In this paper, by using superfine sand of Liao River basin to prepare the superfine sand concrete, and using scanning electron microscope to observe the different water-cement ratio secondary interface microstructure under the condition of superfine sand concrete. Also the energy spectrum analysis is used to analyze the product of interface hydrated calcium silicate gel (C-S-H gel), and the influence of different water-cement ratio on the secondary interface microstructure and the interface of C-S-H calcium silicon gel ratio is calculated.The results show that:(1) The compressive strength measurement results:The of concrete water-cement ratio0.45of the compressive strength is the largest.(2)The scanning electron microscope Low water-cement ratio of the secondary interface microstructure is denser than high water cement ratio, it also has certain influence on compressive strength of superfine sand concrete.(3)Energy spectrum analysis results:The secondary interface C-S-H calcium silicon gel of water-cement ratio0.45in the superfine sand concrete is the minimum, and the other C-S-H calcium silicon gel ratio of the secondary interface area are between1.5and2.1.In this paper, from the micro angle of the superfine sand concrete, and it has the innovative in the field of superfine sand concrete research. On the basis of predecessors’ research, we put forward the superfine sand concrete secondary interface problems, and provide theoretical reference for the superfine sand concrete research in the future.