Assessment of material characteristics of ancient concretes,Grande Aula,Markets of Trajan,Rome |
| |
| Authors: | Marie D. Jackson John M. Logan Barry E. Scheetz Daniel M. Deocampo Carl G. Cawood Fabrizio Marra Massimo Vitti Lucrezia Ungaro |
| |
| Affiliation: | 1. Department of History, PO Box 6023, Northern Arizona University, Flagstaff, AZ 86011-6023, USA;2. Department of Geological Sciences, University of Oregon, Eugene, OR 97403, USA;3. Center for Dirt and Gravel Studies, North American Refractories Building, Room 151, The Pennsylvania State University, 3127 Research Drive, State College, PA 16801, USA;4. Department of Geosciences, PO Box 4105, Georgia State University, Atlanta, GA 30302, USA;5. Department of Civil and Environmental Engineering, PO Box 15600, Northern Arizona University, Flagstaff, AZ 86011-15600, USA;6. Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, Rome 00143, Italy;7. Sovraintendenza per i Beni Culturali del Comune di Roma, Ufficio Fori Imperiali, Via Quattro Novembre 94, Rome 00187, Italy;8. Sovraintendenza ai Beni Culturali, Servizio V, Museo dei Fori Imperiali, Museo della Civiltà Romana, Coordinamento Progetti Multimediali, Servizio Civile, Progetti Europei, Via Quattro Novembre 94, Rome 00187, Italy;1. Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Praha 6, Czech Republic;2. Institute of Theoretical and Applied Mechanics AS CR, Prosecká 76, 190 00 Praha 9, Czech Republic;1. Instituto Superior de Engenharia de Lisboa, Área Departamental de Engenharia Civil, Portugal;2. Laboratório Nacional de Engenharia Civil (LNEC), Lisboa, Portugal;1. Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720, USA;2. King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia;1. Jiangsu Key Laboratory for Construction Materials, Southeast University, Nanjing 211189, People’s Republic of China;2. Department of Civil and Environmental Engineering, UC Berkeley, Berkeley, CA 94720, USA;3. Department of Thermal Energy, Shanxi Institute of Technology, Xi’an 710300, People’s Republic of China |
| |
| Abstract: | The Grande Aula, or Great Hall, of the Markets of Trajan (AD 96 to 115) is an intact example of the domed, concrete architecture of imperial Rome. Petrographic, x-ray diffraction, chemical, and SEM analyses demonstrate that wall mortars contain Pozzolane Rosse volcanic ash aggregate (harenae fossiciae) and strätlingite, a complex calcium aluminate cement hydrate (C2 ASH8) that gives modern cements good durability and compressive strength. Specific gravity tests and a new petrographic method for assessing bulk densities indicate unit weights of about 1750 kg/m3 for the wall mortars and 1430–1640 kg/m3 for the pumice bearing, vaulted ceiling mortars. Innovative point load source tests record the tensile strengths (ft) of the aggregate and interfacial elements of the conglomeratic concrete fabric. These suggest ft of about 2.7 MPa for brick, 1.2 MPa for Tufo Lionato tuff, and 0.9 MPa for Tufo Giallo della Via Tiberina tuff coarse aggregate (caementa), based on a tentative, approximate correlation with splitting (Brazilian) tests. The pozzolanic mortar and interfacial zones have lower ft in the range of 0.8 MPa to 0.5 MPa. The relatively low mortar strength and its somewhat tenuous adhesion to the coarse aggregate suggests that the caementa may have arrested the propagation of tensile microcracks that formed in the mortar, thereby increasing the composite tensile strength of the concrete. Roman builders selected the complex aggregate mixes to optimize the performance of the wall and vault concretes. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
