Freezing Damage Analysis And Remedy Study Of Cement Concrete Pavement

Concrete is one of the most widely used construction materials all over the world , but more and more concrete structures undergo deterioration due to less of durability. Concrete durability not only affect many properties of building materials, but also influence those goals of successive development of national environment.Durability is one of the most miportant properties to evaluate the quality of concrete. Lots of achievements and experiences in this field have been reported .A great deal of sound suggestions to improve the durability of concrete have been proposed. Although materials science and technology have being highly developed, there are still many problems remained unresolved by now when concrete structures are exposed in severe environment. For example, in the frost environment, salt scaling is the most common damage type of concrete in the presence of deicing salt. In the light of construction experiences, the surface of Qin Huang Dao city concrete road has been eroded in large areas because of the salt scaling. Many aspects about deicing salt were investigated such as its characteristics, causation and mechanism.In respect that the ordinary cement mortar has disadvantages, such as low adhesive strength, bad seepage-proof and low tensile strength. This paper through course analysis and alternatives demonstration, a kind of high performance polymer mortar is developed by means of combination of organic and inorganic material. It nas high hardens strength, large tensile strength and better anti-freeing as well as shock strength .Being characterized with strong adhesion to concrete ,the polymer mortar may be adopted as repairing material for the eroded surface layer of the deck plate .Relevant research and application show that this new polymer mortar can significantly counteract the deficiency of ordinary concrete and possesses excellent mechanical and pavement properties, It's larger economical and social effect is obvious0This paper described the material properties of fiber reinforced concrete, basing on a series of experiments and theoretical analysis. Considering three factors which are polypropylene fiber, steel fiber, expanding agent, compressing, split-tendile and flexural strength of this kind of composite were studied.According to the problems of concrete durability, serials of new experimental methods that combine the action of freezing-thawing cycles and deicing salt to concrete were designed to evaluate the durability of concrete. It was shown that after adding a certain amount of polypropylene shore fiber to the mixing material of concrete, cracks on concrete at early stage are affectively prevented and the permeability of concrete is obviously reduced, thus tne durability of concrete is improved. The properties of polypropylene concrete under the combined action or two damage factors and its synergetic effect were investigated systematically. Through experiment and theoretical analysis, this paper summed up damage resistance synergetic effect of polypropylene fiber, steel fiber and expanding agent.Based on the systematic experiments and theoretical analysis, the damage of concrete subjected to the action of combined several deterioration factors can be considered as a low cycle fatigue process, primarily caused by freezing-thawing cycle .The periodic stress was exerted to concrete specimen during freezing and thawing .The stress distributing in the whole concrete specimen could be simplified as the stress condition of tension in three direction .The stress level of concrete immersed in solution was a little smaller than that in fresh water during freezing and thawing.