The Research Of Using The Cold Draw Multiple Thread Steel Bar's Concrete Slab's Crack Question

At present architectural engineering in our country applicate cold draw multiple thread steel bar concrete floor, however in actual project more universal appearance were found kinds of crack. Crack in floor, will make influence immediately to the project's appearance quality, and should be done again. Moreover, it will lead to the building structure security and the physical mechanics and impervious, anti-pull, the anti-chemical mediator to corrode, performance and so on. Creates the cement concrete service life big reduction, maintains the repair expense to rise massively, therefore is receiving people's close relation in the last few years using the cold draw multiple thread steel bar's concrete slab's crack question.The introduction turns the shape enhancement material from the introduction of the historical development to start, has made the simple introduction to the concrete slab dehiscence present situation as well as the crack harm. Then cracked the question to the concretes itself to carry on a more detailed introduction, from caused the concretes itself to crack first obtains, to introduce the concretes dehiscence's primary cause, and elaborated in the construction in each stage possibly to cause the concretes dehiscence reason in detail. The third chapter introduced in detail the cold draw multiple thread steel bar characteristic and the use matters needing attention, elaborated the cold draw multiple thread steel bar crack's width formula as well as 3 influencing factors, and determined uses this kind of steel bar C value influence to be more obvious than the light round. Here explained belongs to the ductility using the cold draw multiple thread steel bar's destruction to destroy, for used this steel bar by the security aspect to make the qualitative analysis.Basing on these relations, I have conducted the field research to in Kunming which use cold draw multiple thread steel bar as the floor stress main reinforcement's work site. Then the connect the work site application cold draw multiple thread steel bar concrete slab scene situation as well as the work site entity intensity examination report, the generalized analysis reason, recognized initially this project floor cracks the primary cause is the upper formation steel bar submersion or shifting, causes the concrete floor partial protector C value to favor, forms the weak spot. From this angle embarking, this article has designed a simple opposite experiment, with examines several related factors which cracks using the cold draw multiple thread steel bar's concrete floor, is mainly the C value (in view of the scene situation).The experimental results showed:Cause the upper formation steel bar protector using the cold draw multiple thread steel bar's concrete slab upper formation steel bar submersion or shifting to favor, serious influence floor's crack resistance energy. And what is the addition is using the cold draw multiple thread steel bar substitution light round, brings the floor ratio of reinforcement drops, is also the reason of this kind of board dehiscence universal substantial. To this', we on request Construction in construction process strict control good board upper formation steel bar submersion question, controls the good steel bar the position. After design substitution must inspect the smallest ratio of reinforcement the problem, avoiding the dehiscence question the floor.This article unifies the results which finally the experiment obtains, as well as front recounted concretes dehiscence reason, in addition cold draw multiple thread steel bar characteristic as well as use limelight. Mainly from the raw material quality, the design pays attention prevents the contraction, the application cold draw multiple thread steel bar must pay attention to the question, construction anticipatory control measure these aspects, proposed some concrete anticipatory control the measure which cracks using the cold draw multiple thread steel bar steel bar's concrete floor.