Advancing Concrete Sustainability through Recycling
报告人：Prof. David A. Lange, 美国混凝土学会（ACI）主席
The goal of material recycling in construction has opened new possibilities for new materials of innovative uses of recycled fines for high value-added applications, including foam concrete that is a low-density controlled low-strength material (LD-CLSM). Due to the high porosity, this material usually has a strength range of 0.2 to 10 MPa, while this untraditional property leaves it a highly crushable nature. A good potential is using foam concrete with recycled fines to make Engineered Material Arresting System (EMAS) for airport runway safety. As such, it is highly needed to characterize the crushing energy and find its material determinants. In this work, several testing approaches have been proposed to fulfill this goal. The basic crushing behavior of foam concrete from 0.4 to 0.8 g/cm3 is investigated using a penetration test. To characterize the void structure on the microstructural level, the geometric features of the actual 3D void structure are characterized using micro CT. A digital image correlation (DIC) test is used to assist the study on material deformation under indentation. Based on the experimental results, two material failure mechanisms, volume collapse and shear, are proposed to explain the energy dissipation of foam concrete indentation. With the aid from the advanced testing techniques, both the modes are qualitatively correlated to the evolvement of the energy consumption at different stages of foam concrete crushing.
David A. Lange is Professor of Civil Engineering at the University of Illinois at Urbana-Champaign. His research area is concrete materials, microstructure property relationships, airport pavements, concrete rail crosstie durability, foamed cement materials, and recycled concrete. He serves as Director of the Center of Excellence for Airport Technology, a research center sponsored by the O’Hare Modernization Program and the Federal Aviation Administration. Lange has published over 100 technical papers and reports, including over 90 refereed journal papers. He is a Fellow of the American Ceramic Society. He is also a Fellow of the American Concrete Institute and winner of its Wason Medal in 2003 and 2018. He serves as President of ACI, member of the ACI Board of Direction, past chair of the ACI Technical Activities Committee, and has served ACI in many other roles.