Tests And Research On Bond Behavior Between Deformed Bar And Lightweight Concrete

As we know, the lightweight aggregate concrete is an ideal building material on account of its properties such as light weight, high heat preservation and inhere fire resistance. It is made of sand, cement and lightweight aggregate, etc. Some of the lightweight aggregates include pumice, stuff, expanded clays (haydite), etc. Now it is widely used in bridge building and civil engineering.In Guangxi region, the research on lightweight aggregate concrete is only beginning, the properties of the new material needs to be further experimented on. The bonding mechanism between deformed bar and lightweight concrete is discussed in this paper based on the pullout test results of 75 specimens. By the analyses of the influence of grout compression strength, anchorage length and bar diameter on anchorage behavior, the formulas of the characteristic strength value and characteristic slip value are attained by means of statistical regression. Based on the pullout test with strain pieces stuck on the internal groove of the bar, the rule of the bonding stress along the anchorage length is studied. In conclusion, the bond anchorage reliability analyses are carried out to validate the safety of anchorage length provided by "Specification for Design of Lightweight Aggregate Concrete Structure (JGJ12-99)" .The experimental results show that the bonding mechanics properties of lightweight concrete, whose coarse aggregate is made of haydite produced in Guangxi region is better than common concrete. The anchorage length of reinforcing bar embedded in lightweight concrete provided by "Specification for Design of Lightweight Aggregate Concrete Structure (JGJ12-99)" is safe.