دانلود رایگان مقاله انگلیسی مطالعه استفاده دوباره از مصالح بتنی بازیافتی برای اجزای باربر سازه ساختمانی - اشپرینگر 2017

Abstract

Recycled aggregates recovered from abandoned buildings or demolished concrete structures were reused to produce concrete columns as new building components. A quasi-static test on 10 recycled aggregate concrete flled steel tubular (RACFST) columns was carried out. The mechanical properties of RACFST columns in the study include failure mode, hysteretic loops, skeleton curves, stifness deterioration curves and energy dissipation capacity. RACFST columns with diferent recycled aggregate replacement ratios were tested under constant axial load and cyclic lateral load. The seismic performance of the columns was analyzed. The experimental results indicate that concrete adding recycled aggregates does not reduce the lateral stifness of the columns, and their energy dissipation capacity is nearly as good as that of natural aggregate concrete flled steel tubular columns. The usage of recycled aggregate concrete has little infuence on the lateral load-bearing capacity and the stifness deterioration of RACFST columns. The current calculation for natural aggregate concrete flled steel tubular columns to estimate the lateral load-bearing capacity of RACFST columns tends to be relatively conservative. The reuse of recycled aggregates for load-bearing components of building structures especially for concrete flled steel tubular columns is feasible.

Conclusion

From the analyses of hysteresis loops, skeleton curves, ductility, stifness deterioration and energy dissipation based on the experimental results of 10 RACFST columns under constant axial compression and cyclic lateral loading, the following conclusions can be obtained.

1. RCA replacement ratio has little efect on the lateral load-bearing capacity of RACFST columns, but the compressive strength of the core concrete does. Adding RCA does not reduce the lateral stifness of RACFST columns, and the curves of stifness deterioration with diferent RCA replacement ratios are substantially the same at the same steel ratio.

2. The energy dissipation capacity of RACFST columns, including those with the thin-wall steel tubes, is not inferior to that of the CFST columns. The steel ratio has a more signifcant infuence on the energy dissipation for the RACFST columns with a RCA replacement ratio of 30% than that with a ratio of 50%, while it has a similar infuence on the stifness deterioration and has little efect on the lateral load-bearing capacity of RACFST columns with diferent RCA replacement ratios.

3. It is rational to use the current standard DB34/T1262- 2010 for the CFST columns to calculate the lateral loadbearing capacity of RAC flled thick-wall steel tubular columns, but it tends to be relatively conservative for the recycled concrete flled thin-wall steel tubular columns.

4. It is technically feasible for recycled aggregate coming from waste building materials to produce concrete flled steel tubular columns, which presents a possible method for high valuable reuse of waste materials in building structures for load-bearing components.