时间：2017年7月6日上午10：30

地点：地坤409

报告人：郝洪 教授

主持人：肖岩教授

报告内容：Concrete is the most widely used construction material due to its impressive resistance to compressive load. The major weaknesses of concrete are its brittleness and poor resistance to tensile forces. Intensive number of studies has been conducted to add various types of short discrete fibres into concrete mix to enhance its ductility and post-peak load-bearing capacity. A spiral-shaped steel fibre was recently proposed for reinforcing concrete material with 3D bond components. A series of laboratory tests have been conducted for a comprehensive investigation of the performances of spiral-shaped steel fibre reinforced concrete materials and structures. A fundamental understanding of the bond-slip behaviour of spiral fibres and its mechanism of reinforcing the matrix was achieved by conducting pull-out tests. Compressive and direct tensile tests onØ100-200 mm concrete specimens with spiral fibres of different geometries were conducted for properly determining fibre geometries to reinforce concrete materials. Split Hopkinson pressure bar (SHPB) tests were carried out to study the dynamic behaviour of spiral steel fibre reinforced concrete (SFRC) with various volume fractions under compression and splitting tension. The corresponding relations of dynamic increase factor (DIF) vs. strain rate were proposed based on test data. Repeated drop-weight impact tests on SFRC beams reinforced with the commonly-used hook-end fibres and spiral fibres were performed. Test results demonstrated the superiority of spiral fibres in bonding and enhancing concrete structural elements in resisting impact loads. The even distributions of spiral fibres in comparison with crimped fibres in concrete matrix were justified by physical examinations. Mesoscale simulations with distinctive consideration of mortar matrix, coarse aggregates and spiral fibres were conducted for statistical derivation of dynamic properties of spiral SFRC. While having demonstrated the promising performances of concrete reinforced with spiral fibres, further studies are also suggested based on the observations and results obtained.

报告人简介：Hong Hao received BEng from Tianjin University, China, MSc and PhD from the University of California at Berkeley, USA. Currently he is John Curtin Distinguished Professor, Director of Research Centre for Infrastructure Monitoring and Protection in Curtin University. He has more than 800 technical publications including over 370 journal papers and 14 edited books and conference proceedings in earthquake engineering, blast and impact engineering and structural condition monitoring. He is one of the most highly cited researchers in civil engineering with H-Index 49 in Google Scholar and 40 in Scopus. He has won more than 20 research, research publication and research supervision awards. He has been invited to give over 50 keynote and many invited presentations in international conferences in many countries. His research results are included in textbooks, adopted in design codes, and used in many construction projects around world. He is the chief editor of International Journal of Protective Structures, and serves in the editorial board of another 10 journals. He was past President of the Australian Earthquake Engineering Society, and has served in many national and international professional committees including expert panel of Australian Research Council. Currently he is Deputy President of the International Association of Protective Structures, Australian Rep in the International Association of Earthquake Engineering, Advisory Board member of Australian Network on Structural Health Monitoring. He is fellow of Australian Academy of Technical Science and Engineering, fellow of Institution of Engineers Australia, fellow of American Society of Civil Engineers, and fellow of International Society of Engineering Asset Management.