中国矿业大学(北京)博士英语 研究生英语作文考试范围

中国矿业大学(北京)博士英语 研究生英语作文考试范围

Analysis report

Date: January 17 ,2013

From: Zhang Liran

To: Zhao Jiaqi

C:Zhang Chengfei

Subject: selection of super plasticizer in cement paste

Objective

To show that PC super plasticizer will increase the dispersion and stability of the fresh cement paste.

Summary

After long-distance transmission, rheological property of cement paste become worse off. This problem will be solved by adding PC super plasticizer, to reduce the cement particles coagulation again.

Introduction

In response to your request that I research the different types of super plasticizer(LS,PNS,PC), in gathering this information, I reviewed many literatures and mode a lot experiments. This report explains the properties of PC in fresh cement paste. The properties consist of dispersion and stability.

Conclusion

Through the performance comparison ,the results are as follows:

1、three types of super plasticizer have the ability to disperse the cement particles, however, PC has stronger dispersion than others.

2、LS has little stability , PNS has a little stability , however, PC has better stability.

Discussion

The cement paste is a suspension of cement particles in water. The different types of super plasticizer have different dispersion. In cement paste with super plasticizer(SP), SP could adsorb on the surface of cement particles. because of the forces of van der waals, electrostatic repulsion and steric hindrance, the cement particles could maintain dispersed state. In cement paste with LS, there are the forces of van der waals among cement particles, cement particles are dispersed by the forces of van der waals and electrostatic repulsion in cement paste with PNS, however, In cement paste with PC, cement particles are dispersed by the forces of van der waals , electrostatic repulsion and steric hindrance.

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