Design Of Damping Concrete With Antivibration Aggregate

The usage amount of concrete is the largest in civil engineering. Damping of concrete has very important influence on anti-vibration performance, stability in use, durability of structures. But the present issue on improving concrete’s damping technology can’t solve contradiction between damping capacity and mechanical property. Based on this, the paper focuses on fine aggregate which has biggish proportion in concrete. Based on absorptivity of porous fine aggregate and rheological property, high damping property of polymer, different type damping aggregate was designed and prepared. Damping aggregate was introduced in concrete to prepare high damping concrete of excellent property with compound using coal ash and mineral powder. The main achievements are as follows:Mechanism on adsorbing and storing polymer of porous fine aggregate and the best preparation technology of damping aggregate were researched. Type I damping aggregate and Type II damping aggregate were prepared by introducing water and polymer in porous fine aggregate under ordinary temperature and pressure; Type III damping aggregate was prepared by polymerization film-forming of styrene-acrylic emulsion on the surface of porous fine aggregate. The influence of damping aggregate species, amount of admixture and extra materials include fiber and rubber powder on damping capacity and mechanical property of mortar was researched. The damping capacity of mortar was significantly improved but mechanical property was not dramatically decreased when mixing amount of 30% Type I, 30% II and 40~50% III were determined preliminarily. Type III damping aggregate had the best damping result. Mixing 0.5~1% fiber could further improve damping function and mechanical property with mixing damping aggregate meanwhile; damping function was significantly improved and mechanical property wasn’t obviously decreased when 2.5% rubber powder was mixed. Film-forming thickness of styrene-acrylic emulsion on Type III damping aggregate was researched and computing method on the best distribution proportion of styrene-acrylic emulsion was deduced.The influence of damping aggregate mixing amount on damping capacity and mechanical property of concrete was researched on the basis of preliminary damping aggregate mixing amount of mortar. High damping concrete, which the mechanical property wasn’t decreased and damping capacity was significantly improved, was prepared. The influence of damping aggregate species, amount of admixture and mineral admixtures include coal ash and mineral powder on durability of high damping concrete was researched. Damping aggregate in the high damping concrete can decrease dry shrinkage rate compared with standard concrete, at the same time, incorporation of mineral admixtures include coal ash and mineral powder can further enhance reducing dry shrinkage result. High damping concrete has the better frost resistance property and resisting sulphate capability compared with standard concrete when damping aggregate and extra materials including coal ash and mineral powder were compounded to use. The mechanical property and durability were considered as two key indexes, which confirmed that the best mixing amount of Type I, Type II and Type III damping aggregates were 40%、30% and 60% respectively in the high damping concrete. In addition, introducing of fiber can further improve frost resistance property and resisting sulphate capability of high damping concrete.Mechanism of damping aggregate in the high damping concrete was researched. The main reasons, which damping aggregate can improve damping capacity, were stretch, warp, relative slippage of meander structure molecular chain of high-molecular polymer and relative deformation produced by the difference elasticity modulus among damping aggregate, set cement and river sand. Mechanical meshing structure is formed between damping aggregate and set cement. The filling effect of hydration products can remedy original flaw on damping aggregate; damping aggregate can play the internal curing role, optimize interfacial transition zone, increase interface hardness and friction to significantly improve damping capacity and weaken the reducing effect on mechanical property.