Structural behaviour of ultra highperformance fibre reinforced concrete slender column under axial loading
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Date
2019-06
Authors
Yeoh Seng Keat
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Abstract
This study was carried out to identify the difference of performance of three different
type of concrete slender column, namely Ordinary Portland Cement (OPC) column,
Ultra- High-Performance Concrete (UHPC) column and Ultra- High-Performance Fibre
Reinforced Concrete (UHPFRC) column. But, it is still unknown what is the extend of
the performance of UHPFRC that far exceeds that of normal concrete. Concrete column
is a critical part in a structure and should possess the highest strength possible. Smooth
micro steel fibres of diameter 0.2 mm and length 10 mm were used in the mix which was
prepared by the study previously. One column sample is prepared for one type of
concrete. The targeted designed compressive strength is from 100 MPa to 120 MPa for
UHPC and UHPFRC column and 50MPa for OPC Column. A total of 5 tests were
conducted on the concrete samples as in accordance to BS1881. They are cube
compression test, tensile splitting test and four-point flexural test. Three column of size
75 mm × 75 mm × 1500 mm were cast for the axial loading test using Universal Testing
Machine. Based on the results, UHPFRC have the highest compressive strength
(96.0MPa), tensile strength (8.3MPa) and flexural strength (14.12MPa) among three
types of concrete. Overall, addition of fibre increases the performance of UHPC.
Additional steel fibre also can bridge the cracks and limiting the crack propagation. As
a result, UHPFRC column can sustain longer the loading and to a higher degree. Thus,
UHPFRC column has higher failure load (277.6kN) compared to UHPC (252.8kN) and
OPC column (173.0kN). Energy absorption capacity of concrete can be defined from the
area below the load- deflection graph. UHPFRC have the highest energy absorption
capacity of 1395.85kN-mm among the three types of concrete, where OPC and UHPC
having energy absorption capacity of 567.7kN-mm and 1218.8kN-mm, respectively.