Study on the Design of Mechanical Sand-Concrete Mixing Ratio for Shield Segment Considering the Effects of Stone Powder
Given that stone powder in mechanical sand mainly acts as a filler in concrete rather than as a framework,treating stone powder as a part of mechanical sand is no longer suitable for designing the mixing ratio of shield segments and mechanical sand concrete.Taking stone powder as a part of the powder,this study considered the impact of stone powder in calculation of the water-powder ratio of shield concrete,introduced the thickness of the mortar coating layer to calculate the aggregate content in the concrete,and also investigated the effect of the thickness of the mortar coating layer on the mechanical sand concrete of the shield segment.As shown by the results,in comparison to the traditional design method,the amount of cement used for mechanical sand concrete designed and prepared through the design method of this study was reduced by about 20 kg/m3,the electric flux and chloride ion diffusion coefficient were reduced by26.7%and25.1%,respectively,and the90-day shrinkage rate was decreased by 33.3%.Furthermore,the workability,chloride ion penetration resistance,and shrinkage resistance of mechanical sand concrete deteriorated significantly as the thickness of the mortar coating layer increased.
mechanical sandstone powdermortar coating layermixing ratio designshield segment
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NSTL
万方数据
维普
