Research On The Concrete Strength Of The Construction Initial Setting And Concrete Strength Evaluation Method

Slip forming construction, that is a construction method which taking slip form-jack, motor hoist or hand powered lift as power, pulling forms slipping along surface of concrete, is a cast-in-situ concrete structure job practice. It's one of the widely using construction methods. Compared with conventional methods, it is faster, higher level of mechanization, well structural integrity and reset and recycle. So the slip forming construction has been widely used and has achieved good economic benefit and social benefit in China.Concrete strength of construction initial setting is the strength when concrete is showed from the bottom of slip form. It is one of the important indexes in slip forming construction and key point that whether the slip form technology can be achieved successfully or not. When it is too low, the concrete will be flowing, fleeing and collapsing; when it is too high, the concrete will be ripping, scratching, loosing, leakiness and in aesthetic. So it must be take seriously for the controlling of concrete strength of construction initial setting.In china, the determination of concrete strength of construction initial setting has two methods:experience judgment and penetration test at present. Experience judgment varies from person to person, may be influenced by many complicated factors such as the weather, temperature and so on, even lead to inestimable loss. Penetration test is easily adopt in laboratories, but not be spread in the construction site. So the C20-C60 concrete are made and test in the experiment. Based on the experimental data and penetration test, the instrument named tester of strength of the construction initial setting is created finally. It can determine the concrete strength simply and faster in the slip forming construction. It's realized that the qualitative analysis changed into quantitative analysis.According to the method of AHP, an index system and evaluation methods about concrete strength is put based on the data of experiment. The evaluation of concrete strength is taken as the general objective, decomposition objectives to different hierarchies as the order of general objective, sub goals and evaluation criteria. By computing judgment matrix, through sort calculating and consistency check, getting the concrete strength index system finally. Then it is tested the system on the construction site, obtaining a more ideal result, guiding the slip forming construction practice well.