随着国民经济和铁路建设的高速发展,钢筋混凝土梁得到了广泛的运用,已占全同铁路桥梁总延长米的90%以上, 在铁路运输生产中发挥“主力军”的作用。但由于长期运营,钢筋混凝土结构会产生表面裂缝,混凝土碳化等病害,降低梁的承载能力,缩短梁的使用寿命,影响铁路运输安全。 1 影响钢筋混凝土梁耐久性的主要原因分析 1．1 混凝土密实度对钢筋混凝土梁耐久性的影响混凝土是由胶结料和骨料混合,通过一定的工艺成型硬化而成的人造石。是一种带有细孔的材料,这些孔道主要来源于水泥浆中多余水分蒸发和泌水后留下的毛细管道,以及粗骨料下缘聚积的水隙。另外也可产生与混凝土浇捣不密实及硬化后因干缩、热胀等变形造成的裂缝。因此,提高混凝土的密实度可以 With the rapid development of national economy and railway construction, reinforced concrete beams have been widely used, accounting for more than 90% of the total extension meters of railway bridges and bridges, playing a “major force” in railway transport production. However, due to long-term operation, the reinforced concrete structure will produce surface cracks and concrete carbonization and other diseases, reduce the bearing capacity of the beam, shorten the service life of the beam and affect the railway transportation safety. 1 main reasons for the impact of durability of reinforced concrete beams 1.1 Concrete Density Durability of reinforced concrete beams Concrete is a mixture of cementitious materials and aggregates, through a certain process of forming hardened artificial stone. Is a material with fine pores that mainly originate from the capillary channels left by excess water evaporation and bleeding in the slurry and the water voids that accumulate on the lower edge of the coarse aggregate. In addition can also produce and concrete pouring is not compacted and hardened due to shrinkage, thermal expansion and other deformation caused by cracks. Therefore, to improve the density of concrete can