Pore Structure Characteristics and Durability Analysis of Fiber Reinforced Concrete
|School||Dalian Jiaotong University|
|Course||Road and Railway Engineering|
|Keywords||polypropylene fiber alkali-resistant glass fiber basalt fiber concrete pore structure SEM durability|
Concrete is engineering materials which is currently used most widely. But concrete is porous brittleness material, the tensile strength is far below the compressive strength and toughness is poor. These weaknesses limit the development of concrete. Because of concrete appears different degree of damage in process, the durability of concrete puts forward higher requirement. Durable concrete when exposed to its working environment, can keep the original shape, function and normal use. It is the important task of international civil engineering. In order to enhance the durability of concrete, we can improve concrete pore structure. In recent years fiber reinforced concretes are studied more and more. This paper mainly studies pore structure characteristics of polypropylene fiber reinforced concrete, alkali-resistant glass fiber reinforced concrete, basalt fiber reinforced concrete and common concrete, and analyzes influence of the fibers on the durability and mechanical properties of concrete.Firstly, the paper tested pore structure characteristics of fiber reinforced concretes by the mercury injection method, mainly analyzed pore size distribution, studied the influence of the fiber on improving pore structure. At the same time the internal structure of fiber reinforced concrete was researched by scanning electron microscope (SEM) analysis, then described the influence of fiber on the internal structure.Secondly, we test mechanical properties of fiber reinforced concrete. The results show that adding a certain amount of three fibers separately into concrete have all increased splitting strength and toughening effect is obvious Compared with common concrete, compressive strength of alkali-resistant glass fiber reinforced concrete and basalt fiber reinforced concrete are both improved. According to analysis, the effect of strengthening and toughening in basalt fiber is particularly significant.Finally, durability of fiber reinforced concrete was tested. Durability mainly contains the permeability resistance and forst resistance in this paper. The permeability experiment mainly has water penetration test and chloride penetration test, then characterize the permeability of fiber reinforced concrete through the seepage height and chloride ions diffusion coefficient. Quick freezing method is used. According to the result of freeze-thaw cycle 100 times we analyze forst resistance of fiber reinforced concrete.