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Xing J.Q.,Zhejiang University | Zhan S.L.,Zhejiang University | Li X.Y.,Huadong Institute of Exploration
Advanced Materials Research | Year: 2014

This paper studies the influence on compressive strength, freezing resistance and microstructure of cement mortar with different content of mica in stone powder, in the tests, manufactured sand with high content of mica and natural river sand were mixed with different proportion, and the content of stone powder was the same in mixed sand. Experiment results indicate that, with the increasing of mica content in stone powder, 28d and 60d compressive strength of cement mortar decreases obvious, mass loss rate and strength loss rate with 50 freeze-thaw cycles increase a little. Microstructure of cement mortar with higher content of mica is not compactly by SEM, the internal defects of cement hardened pastes could be increased because of the flake mica which surface is smooth, and it will cause the spread of micro crack. © (2014) Trans Tech Publications, Switzerland. Source

Huo J.,Hohai University | Song H.,Hohai University | Guo Y.,Hohai University | Peng P.,Huadong Institute of Exploration
Shuili Fadian Xuebao/Journal of Hydroelectric Engineering | Year: 2013

Contact dissolution is a main influencing factor on the durability of hydraulic concrete. An experiment was conducted in this work to study the contact dissolution of cement paste, fly ash cement and slag cement, focusing on different contact areas under deionized water of low ratio of liquid-to-paste mass. For each material, an equation was derived to fit the electrical conductivity of all the periods and predict the peak dissolution in each period, and the variation of calcium concentration can be derived from its relationship with electrical conductivity established in this study. As a conclusion, addition of the slag or fly ash into these cements can reduce the leaching of salts and calcium, especially the addition of slag that has a better resistance, and the amount of dissolved salts depends on the surface area of samples and the volume of solution. Source

Liu Q.,State Key Laboratory of Water Resources and Hydropower Engineering Science | Liu Q.,Chongqing Three Gorges University | Hu Z.,State Key Laboratory of Water Resources and Hydropower Engineering Science | Hu Z.,Chongqing Three Gorges University | And 2 more authors.
Shuili Fadian Xuebao/Journal of Hydroelectric Engineering | Year: 2014

Risks in a construction and diversion system of hydropower project with cascaded reservoirs depend on the flood control of upstream reservoirs and downstream reservoir operation and environmental control. This paper develops a diversion risk evaluation model that simulates flood discharge process to couple the major factors, such as upstream water release, interval-basin flood, branch afflux, and construction of upstream and downstream stations, upstream reservoir regulation, river channel storage, and uncertainties in natural flood, upstream station discharge capacity, branch afflux and its superposition method, interval-basin flood, downstream reservoir backwater level, and construction diversion system. This model uses Monte-Carlo Method to evaluate diversion risk. The present study provides references for the decisions on the diversion standard of Baihetan project on the lower Jinsha River. Copyright. Source

Li X.,Huadong Institute of Exploration | Ren J.,Huadong Institute of Exploration | Chen Y.,Huadong Institute of Exploration
Shuili Fadian Xuebao/Journal of Hydroelectric Engineering | Year: 2012

The mica content of stone powder in manufactured sand is higher when the sand is made by crushing rocks of higher mica content. The effect of mica content in stone powder on the performances of manufactured sand concrete is experimentally studied in this work, with the mica content controlled by adjusting stone powder content of manufactured sand from 6% to 18%. Experimental results show that the stone powder with high content of mica has adverse effects upon concrete performances, such as water content, workability and tensile strength etc. With higher content of mica in stone powder, the concrete will have higher water content, worse workability and lower tensile strength. And the ratio of tensile strength to compressive strength is lower. Source

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