Secara teorinya, sifat-sifat konkrit seperti kekuatan, kemuluran, dan resapan tenaga boleh ditingkatkan dengan mencampur aggregat getah remah daripada tayar terbuang. Oleh itu, tujuan penyelidikan ini adalah untuk menyokong kekurangan kajian-kajian terdahulu dengan memfokuskan kekerasan dan kelakuan impak konkrit yang mengandungi aggregat getah remah disatukan dengan gentian keluli. Sebahagian aggregat halus diganti dengan getah remah pada sukatan 5%, 10%, 15%, 17.5%, 20%, 22.5%, dan 25%. Ditambah pula dengan gentian keluli tercangkuk sebanyak 0.5% secara isipadu serta nisbah aspek 80 dan 60 mm panjang. Beberapa spesimen termasuk selinder, rasuk dan papak telah disediakan untuk menyiasat kekerasan dan kelakuan impak konkrit bergetah yang mengandungi gentian keluli. Sifat-sifat lain seperti tenaga pecah, keamatan tegasan, kadar lepasan keterikan kritikal and J-integral juga turut dikaji. Pada awalnya, rintangan impak rasuk diperolehi menggunakan jatuhan tukul 4.54 kg manakala untuk kelakuan impak konkrit tetulang bergentian dan tanpa tetulang, alatan menggunakan jatuhan beban sebanyak 2.5 kg telah dilakukan. Simulasi dilakukan dengan FEM dan LUSAS V14 bagi meramal kelakuan beban pesongan rasuk dibawah beban impak. Didapati persamaan yang munasabah dicapai antara nilai ramalan dan dapatan kajian ekperimen ujian impak. Diperhatikan tenaga impak papak konkrit dibawah halaju-rendah jatuhan bebola besi meningkat dengan peningkatan getah hancur bagi konkrit gentian keluli dan tanpa gentian keluli sehingga 20%. Walaubagaimanapun, pengurangan tenaga impak berlaku apabila nisbah pengantian aggregat halus kepada getah hancur melebih 20%. Kesimpulannya, konkrit bergetah yang mengandungi gentian keluli memperlihatkan potensi prestasi yang baik dibawah beban impak dan akhirnya boleh mempromosikan alam sekitar yang sihat menggunakan tayar terbuang.
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Theoretically, concrete properties such as toughness, ductility, and energy absorption capacity can be improved by adding crumb rubber aggregate from waste tires. Therefore, this intended research work is to support the lack of previous studies by focusing on toughness and impact behavior of concrete containing crumb rubber aggregates with steel fiber. Fine aggregates were partially replaced by crumb rubber at 5%, 10%, 15%, 17.5%, 20%, 22.5%, and 25%. Additionally, 0.5% by volume of hooked end steel fiber was used with an aspect ratio of 80 and 60mm in length. Several specimens including cylinders, beams and slabs were prepared to investigate the toughness and impact behaviour of steel fiber concrete containing crumb rubber. Other properties such as fracture energy, stress intensity, critical strain energy release rate, and J-integral were also investigated. A preliminary impact resistance of beams was obtained using 4.54 kg falling hammer whereas for impact behavior of plain and steel fiber-reinforced rubberized concrete, an instrumented machine of 2.5 kg falling load was used. Simulation was carried out using FEM with LUSAS V14 to predict load deflection behavior of these beams under impact load. A reasonable good agreement was attained between the predicted values and experimental results of impact test. It was noticed that the impact energy of concrete slabs under low-velocity falling iron ball has increased with the increase of crumb rubber in both normal and steel fiber concrete up to 20%. However, a reduction of impact energy was observed when the replacement ratio of fine aggregate by crumb rubber was more than 20%. In conclusion, rubberized concrete containing steel fiber has shown a potential better performance under impact load which could eventually promote healthy environment using recycled waste tires.
Effect of crumb rubber aggregate on toughness and impact energy of steel fiber concrete_Ahmed Tareq Noaman_A9_2017_MYMY