Vizcayno C.,Institute for Natural Resources |
de Gutierrez R.M.,University of Valle |
Castello R.,Institute for Agricultural science |
Rodriguez E.,University of Valle |
Guerrero C.E.,University of Valle
Applied Clay Science | Year: 2010
This paper compares the pozzolanic activity of metakaolin (MK) obtained by thermal treatment at 700°C for 1. h and amorphous kaolin obtained by mechanochemical treatment in a Herzog oscillating mill for 15-120. min. The starting materials used included two raw kaolins and an industrial (washed) kaolin. The production of the amorphous materials was followed by their thermal analysis (DTA, TGA), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), particle size distribution (PSD) and transmission electron microscopy (TEM). The pozzolanic activity of the amorphous kaolins was assessed in accordance with ASTM C 311. Based on the results, both types of treatment allow reactive pozzolans to be obtained from kaolinite clays. The pozzolan obtained by mechanochemical treatment of raw kaolin with high quartz content was found to perform especially well. In sample KV2, with a minor amount of kaolinite, it was possible to obtain an active pozzolan by mechanical treatment but not by thermal treatment. The pozzolanic index and the mechanical resistances obtained by grinding were similar to the thermal treatment. The outcome of the mechanochemical process depends on the type of kaolin used and its and mineralogical composition, and also on its grinding time. © 2009 Elsevier B.V.
Kagan J.S.,Institute for Natural Resources |
Shilling F.S.,University of California at Davis |
Gaines L.J.,Institute for Natural Resources
Transportation Research Record | Year: 2014
Measurement and crediting tools for ecosystem services are important to the processes of transportation planning and project implementation because these tools can aid in mitigating environmental impacts by reducing transaction costs, improving environmental outcomes, and shortening the time needed to implement projects. Because of this importance, such tools have been identified as a key step in the Eco-Logical framework to integrate transportation and conservation planning, characterized by a SHRP 2 capacity program study as the Integrated Ecological Framework. Currently, throughout much of the United States, there are no straightforward methods for the creation of transportation-centric crediting programs. However, successful programs in California, North Carolina, Oregon, and Washington have developed approaches cooperatively with regulatory agencies, state and nongovernmental conservation programs, those actively involved in mitigation banking, and agencies or organizations that fund restoration activities. An overview of crediting systems and valuation methods and their use at various scales in transportation planning are presented in this paper. Current projects and programs are evaluated to identify the opportunities and the obstacles that transportation organizations may encounter when attempting to implement a crediting program.