The Research Of The Relationship Of Early Swelling Of Cement Past In Bellows Of Press-stressed Concrete Post-tension Beam And Crack Generation Following To Orientation Of Bellows

The concrete is a kind of brittleness material. Its tensile strength is only to the press strength for 1/8-1/20, So when the tensile stress produced by the inner part deformation or transmutative force of external world by the constraint condition greater than its tensile strength, the concrete will appear crack. The crack phenomenon in the press-stressed concrete structure is very widespread. Though most crack widths at 0.2mm in, will not influence the structure safety and the usage fuction of the structure, in term of the importance of press-stressed concrete structure, the crack influence the durability of structure directly. No matter what reason it is output crack, should cause the civil engineers and the researchers' value, Be one of the main common failings the crack to carry on prevention and cure, reduce and avoid the emergence of the crack phenomenon.This text mainly carry on analysis about aiming at western region the some large railroad 32 meter press-stressed concrete post-tension beam, appear following to orientation of bellows creation crack of reason and prevention and cure measures. Because the high attitude localities, the stern climate, it is in really rare at home and abroad. Its specific characteristic is : the year mean temperature is placed in -2℃ — -6℃,in winter long 8 month, the day difference in temperature is 25℃ or so. Extreme and lowest air temperature is -45℃ or so. The ultraviolet ray projects light upon mightiness, the strong wind number is more, usually having constantly changing four classes above wind ,a day in it is thus clear that all the year round weather ,such as sometimes fair, timely rain, hour strong wind, timely hail, the disaster weather is more .Although relative humidity 50% is or so, the existence is dry and wet change a multifariouse problem. These factors will make the concrete produce some unrecovered deform. This deform to be subject to restriction will result in the concrete crack. The specially outstanding is the crack follows to the orientation of the beam's bellows. This text mainly analyse the relationship between the reason of the crack and the frost heaving of mudjack material through series of experiments. To prevent appear engineering quality problem again in the later similar engineering, it is very important realistic significance, and also provide certain date analysis for the durable that raises the crack beam.