scholarly journals Confinement of Recycled Aggregate Concrete (M-20) Using U-PVC Pipe

There is a issue of rusting and brittle failure in building structures so there is a need of more durable structure for better performance. The durability of the structure is affected by the choice of the construction material only .But here our main focus is not only to increase the durability but we are also aiming towards increasing the strength of the structure which can be achieved by the confinement of the column. Studies shows that by confining the column, its strength can be increased significantly. From durability point of view, we have carried out the complete replacement of the natural coarse aggregate with the recycled aggregate in order to know its properties and suitability as a replacement material and to promote the idea of sustainable development. In the present paper, an experimental study is presented regarding the load carrying capacity of the unplasticized poly vinyl chloride (U-PVC) confined columns subjected to axial compressive load. The cylinders that are used for this study are M20 grade concrete cylinders which are made using the recycled coarse aggregates. The cylinders are confined using the U-PVC pipes of 2.5mm & 3.5mm thickness and epoxy resin was used to increase the bond strength between the concrete cylinders & the U-PVC pipes. The cylinders that are used in this study are of length 300mm & diameter 150mm. The concrete used in study are designed as per the latest versions of Indian Standard Code of Practice and are prepared after running various trial mixes. A total of 9 specimens were casted for this study out of which 6 specimens were confined using U-PVC pipes while the other 3 specimens were unconfined. The specimens were subjected to gradual compressive load in universal testing machine (UTM) upto the failure and the results were recorded. The results indicated significant increase in the load carrying capacity of the confined columns as compared to the unconfined columns

2017 ◽  
Vol 26 (6) ◽  
pp. 096369351702600
Author(s):  
Min Hou ◽  
Jiangfeng Dong ◽  
Lang Li ◽  
Shucheng Yuan ◽  
Qingyuan Wang

In order to make an effective use of the recycled aggregate concrete (RAC), a total of six steel tube RAC columns and six basalt fiber (BF) reinforced RAC columns, including six columns that were externally strengthened with aramid fiber reinforced polymer (AFRP) sheets, were fabricated and tested. This were to provide a strengthening solution to upgrade the load carrying capacity, ductility and rigidity of the RAC filled steel tube columns. Besides, the recycled coarse aggregate (RCA) replacement ratios for production of RAC was analyzed. The results show that the load carrying capacity and ultimate displacements of the RAC filled ST columns could be improved greatly by adding of basalt fiber, especially for the specimens with 50% and 100% RCA replacement ratio. The similar result was also found for the specimens strengthened with AFRP reinforcement, along with the stiffness of the columns were enhanced obviously. Moreover, the highest improving on the load carrying capacity, stiffness and ultimate displacement was found in the specimens both reinforced by adding of BF and strengthening of AFRP. However, the failure modes of the specimens with BF reinforced RAC gave a higher deformability than the one with AFRP strengthening arrangement.


2012 ◽  
Vol 463-464 ◽  
pp. 234-238 ◽  
Author(s):  
Dong He ◽  
Jiang Feng Dong ◽  
Shu Cheng Yuan ◽  
Qing Yuan Wang

In order to significantly increase not only the load carrying capacity but also the ductility of the steel tube columns filled with recycled aggregate concrete from the earthquake waste, two different strengthening methods by using externally bonded of carbon fibre reinforced polymer (CFRP) to strengthened the columns was proposed. Composite columns of CFRP reinforced and steel circular steel tube columns are studied in this study. The aims were to study the contribution of the CFRP sheets applied in enhancing the load carrying capacity and ductility of the steel tube columns with different concrete type, normal concrete and recycled aggregate concrete. The results demonstrate that the ultimate load carrying capacity and ductility of the steel tube columns filled with recycled aggregate concrete can be increased satisfactorily by full wrapping and partial wrapping arrangement of CFRP sheets. Moreover, stiffness of the columns strengthened was also increased greatly due to the restraining effect offered by CFRP and the full wrapping arrangement is better than the partial wrapping arrangement in enhancing the stiffness and the load carrying capacity.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Anandakumar Ramaswamy ◽  
Selvamony Chachithanantham ◽  
Seeni Arumugam

This paper deals with the behaviour of basalt fibre reinforced polymer (BFRP) composites retrofitted RCC piles subjected to axial compression loads. Currently the awareness of using FRP increases rapidly in engineering fields and also among public. Retrofitting becomes vital for aged and damaged concrete structures, piles, and so forth, to improve its load carrying capacity and to extend the service life. The load carrying capacity of piles retrofitted with basalt unidirectional fabric was studied experimentally. 15 nos. of RCC end bearing pile elements were cast with same reinforcement for axial compression experiment. Three piles were used as conventional elements, another 3 piles were used as double BFRP wrapped pile elements, and remaining 9 piles were used as retrofitted piles with BFRP double wrapping after preloaded to 30%, 60%, and 90% of ultimate load of conventional element. The effects of retrofitting of RCC pile elements were observed and a mathematical prediction was developed for calculation of retrofitting strength. The stress vs. strain relationship curve, load vs. deformation curve, preloaded elements strength losses are tabulated and plotted. Besides, crack patterns of conventional elements and tearing BFRP wrapped elements were also observed. The BFRP wrapped elements and retrofitted elements withstand more axial compressive load than the conventional elements.


Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2956
Author(s):  
Hubert Debski ◽  
Sylwester Samborski ◽  
Patryk Rozylo ◽  
Pawel Wysmulski

This study investigates the effect of eccentric compressive load on the stability, critical states and load-carrying capacity of thin-walled composite Z-profiles. Short thin-walled columns made of carbon fiber-reinforced plastic composite material fabricated by the autoclave technique are examined. In experimental tests, the thin-walled structures were compressed until a loss of their load-carrying capacity was obtained. The test parameters were measured to describe the structure’s behavior, including the phenomenon of composite material failure. The post-critical load-displacement equilibrium paths and the acoustic emission signal enabling analysis of the composite material condition during the loading process were measured. The scope of the study also included performing numerical simulations by finite element method to solve the problem of non-linear stability and to describe the phenomenon of composite material damage based on the progressive failure model. The obtained numerical results showed a good agreement with the experimental characteristics of real structures. The numerical results are compared with the experimental findings to validate the developed numerical model.


1994 ◽  
Vol 21 (3) ◽  
pp. 396-403 ◽  
Author(s):  
Murray C. Temple ◽  
Sherief S. S. Sakla

Angles used as web members in trusses are often welded to the chords with unbalanced welds. This is necessary because of space limitations. It is not known what effect such a weld has on the compressive load carrying capacity of an angle. The standards and specification examined allow an unbalanced weld for an angle. The justification for using such a weld is based on research conducted on angles in tension. For these members, it was concluded that an unbalanced weld does not affect the tensile load carrying capacity of the angle. Research results for angles with different weld patterns subjected to compressive loads are not available in the literature. Eighteen tests were conducted on angle compression members with various weld patterns. It was determined that an unbalanced weld is detrimental to the load carrying capacity of an intermediate length angle but is beneficial for a slender angle. Key words: angles, column (structural), compressive resistance, effective length, standards, welds.


1986 ◽  
Vol 10 (3) ◽  
pp. 149-152 ◽  
Author(s):  
A. M. Brown ◽  
M. J. Pearcy

The chairbound, disabled person requires a supportive cushion to distribute pressure in order to reduce the risk of pressure sores and any alteration to the load carrying capacity of the cushion may have a deleterious effect on its ability to provide adequate support. The National Health Service supplies two basic grades of polyurethane foam for wheelchair cushions and this study investigated the effect of water content on their compressive load carrying capacity. Both foams became less stiff and exhibited greater than 20% increase in deformation when containing 20% water by volume at loads encountered in seating. This decrease in stiffness may result in a dramatic change in the pressure distribution under a patient particularly if only a small section of the cushion becomes wet. This result emphasizes the need to fit waterproof coverings to these foam cushions and to maintain the integrity of the covering.


Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 75
Author(s):  
Huynh-Xuan Tin ◽  
Ngo-Thanh Thuy ◽  
Soo-Yeon Seo

Various researches have been performed to find an effective confining method using FRP sheet in order to improve the structural capacity of reinforced concrete column. However, most of these researches were undertaken for the columns subjected to concentric compressive load or fully confined RC columns. To date, it remains hard to find studies on partially FRP-confined RC columns under eccentric load. In this manner, an experimental investigation was carried out to assess the performance of rectangular RC column with different patterns of CFRP-wrap subject to eccentric loads in this paper. The experiment consists of fourteen mid-scale rectangular RC columns of 200 mm × 200 mm × 800 mm, including five controlled columns and nine CFRP-strengthened ones. All CFRP-strengthened columns were reinforced with one layer of vertical CFRP sheet with the main fiber along the axial axis at four sides, then divided into three groups according to confinement purpose, namely unconfined, partially CFRP-confined, and fully CFRP-confined group. Two loading conditions, namely uniaxially and biaxially eccentric loads, are considered as one of the test parameters. From the test of uniaxial eccentric load, partial and full CFRP-wraps provided 19% and 33% increased load-carrying capacity at an eccentricity-to-column thickness ratio (e/h) of 0.125, respectively, compared to controlled columns, and 8% and 11% at e/h = 0.25, respectively. For the partially CFRP-confined columns subjected to biaxial eccentric load with e/h = 0.125 and 0.25, the load-carrying capacities were improved by 19% and 31%, respectively. This means that the partial confinement with CFRP effectively improves the load-carrying capacity at larger biaxial eccentric load. It was found that the load-carrying capacity could be properly predicted by using code equations of ACI 440.2R-17 and Fib Bulletin 14 Guideline for the full CFRP-confined or partially CFRP-confined columns under uniaxial load. For partially CFRP-confined columns under biaxial loading, however, the safety factors using the Fib calculation process were 20% to 31% lower than that of uniaxially loaded columns.


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