Kajian ini dijalankan untuk mengenal pasti perbezaan prestasi tiga jenis tiang konkrit yang berbeza, iaitu tiang Ordinary Portland Cement (OPC), tiang Ultra High-Performance Concrete (UHPC) dan tiang Ultra High Performance Fibre Reinforced Concrete (UHPFRC). Licin gentian keluli yang mempunyai garis pusat 0.2 mm dan panjang 10 mm digunakan dalam campuran konkrit yang telah siap disediakan. Sebelum ini, satu sampel tiang konkrit akan disediakan bagi satu jenis konkrit. UHPC dan UHPFRC direka bentuk dengan kekuatan mampatan yang disasarkan adalah dari 100 MPa hingga 120 MPa tetapi hanya 50MPa untuk tiang OPC. Sebanyak 5 ujian telah dijalankan ke atas sampel konkrit mengikut BS1881. Mereka adalah kiub ujian mampatan, ujian membelah tegangan dan ujian lenturan empat titik. Tiga tiang bersaiz 75 mm × 75 mm × 1500 mm akan diguna untuk ujian beban paksi menggunakan Universal Testing Machine. Berdasarkan keputusan yang didapati daripada ujian, UHPFRC mempunyai kekuatan mampatan (96.0MPa), kekuatan tegangan (8.3MPa) dan kekuatan lenturan (14.12MPa) yang tertinggi di kalangan tiga jenis konkrit. Secara keseluruhan, penambahan gentian keluli meningkatkan prestasi UHPC. Penambahan gentian keluli juga boleh merapatkan retak dan mengehadkan penyebaran retak. Akibatnya, tiang UHPFRC boleh menanggung beban yang lebih tinggi. Oleh itu, tiang UHPFRC mempunyai beban kegagalan yang lebih tinggi (277.6kN) berbanding dengan tiang UHPC (252.8kN) dan tiang OPC (173.0kN). Tenaga keupayaan penyerapan konkrit boleh ditakrifkan dari graf load- deflection. UHPFRC mempunyai kapasiti penyerapan tenaga tertinggi iaitu 1395.85kN-mm antara ketiga- tiga jenis konkrit. OPC dan UHPC pula mempunyai kapasiti penyerapan tenaga iaitu 567.7kN-mm dan 1218.8kN-mm, masing-masing.
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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.
Structural behaviour of ultra high-performance fibre reinforced concrete slender column under axial loading / Yeoh Seng Keat