Axial compression behavior of recycled-aggregate-concrete-filled GFRP–steel composite tube columns

2020 ◽  
Vol 216 ◽  
pp. 110676 ◽  
Author(s):  
Yunchao Tang ◽  
Shu Fang ◽  
Jieming Chen ◽  
Liangyi Ma ◽  
Lijuan Li ◽  
...  
Keyword(s):  
Axial Compression ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Compression Behavior ◽  
Aggregate Concrete ◽  
Composite Tube ◽  
Steel Composite

scholarly journals Discrete Element Mesoscale Modeling of Recycled Lump Concrete under Axial Compression

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3140 ◽  
Author(s):  
Yong Yu ◽  
Bo Wu
Keyword(s):  
Mechanical Properties ◽  
Axial Compression ◽  
Discrete Element ◽  
Relative Strength ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Ordinary Concrete ◽  
Coarse Aggregates ◽  
Spatial Locations

In the past decade, directly reusing large pieces of coarsely crushed concrete (referred to as demolished concrete lumps or DCLs) with fresh concrete in new construction was demonstrated as an efficient technique for the recycling of waste concrete. Previous studies investigated the mechanical properties of recycled lump concrete (RLC) containing different sizes of DCLs; however, for actual application of this kind of concrete, little information is known about the influence of the spatial locations of DCLs and coarse aggregates on the concrete strength. Moreover, the mechanical responses of such a concrete containing various shapes of DCLs are also not well illustrated. To add knowledge related to these topics, two-dimensional mesoscale simulations of RLC containing DCLs under axial compression were performed using the discrete element method. The main variables of interest were the relative strength of the new and old concrete, the distribution of the lumps and other coarse aggregates, and the shape of the lumps. In addition, the differences in compression behavior between RLC and recycled aggregate concrete were also predicted. The numerical results indicate that the influence tendency of the spatial locations of DCLs and coarse aggregate pieces on the compressive stress–strain curves for RLC is similar to that of the locations of coarse aggregates for ordinary concrete. The strength variability of RLC is generally higher than that of ordinary concrete, regardless of the relative strength of the new and old concrete included; however, variability has no monotonic trend with an increase in the lump replacement ratio. The mechanical properties of RLC in compression are little influenced by the geometric shape of DCLs as long as the ratio of the length of their long axis to short axis is smaller than 2.0. The compressive strength and elastic modulus of RLC are always superior to those of recycled aggregate concrete designed with a conventional mixing method.

Experimental Study on CFRP-PVC Confined RAC under Axial Compression

2019 ◽  
Vol 294 ◽  
pp. 143-149
Author(s):  
Jie Qun Lu ◽  
Yuan Tian ◽  
Jia Geng Chen ◽  
Chen Yu Zhu ◽  
Fu Yuan Zeng ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Axial Compression ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Peak Strain ◽  
Aggregate Concrete ◽  
Compression Performance ◽  
Reinforced Polymer ◽  
Pvc Pipe

Compared with natural aggregate concrete (NAC), the cylinder compressive strength and elastic modulus of Recycled aggregate concrete (RAC) are decreased, but the brittleness is increased. The axial compression performance of RAC can be improved by external confinement. In this paper, the effects of Polyvinyl chloride (PVC) pipe confinement and composite confinement of PVC pipe and Carbon Fiber Reinforced Polymer (CFRP) on the axial compression performance of RAC were investigated. The results showed that with the increase of the replacement rate of recycled coarse aggregate, the cylinder compressive strength, peak strain and elastic modulus of RAC were decreased; PVC pipe confinement could significantly improve the cylinder compressive strength, peak strain and elastic modulus of RAC; the CFRP could further improve the cylinder compressive strength and elastic modulus of PVC-RAC to a certain extent, and could significantly enhance the peak strain of PVC-RAC. PVC pipe and CFRP-PVC pipe confinement could improve the axial compression performance of RAC more effectively than NAC. Consequently, PVC pipe and CFRP-PVC pipe confinement could reduce the influence of recycled aggregate (RA) quality on variability of RAC axial compression performance.

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