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Certification of SRM 2497

其他書名	Standard Reference Concrete for Rheological Measurements
出版	U.S. Department of Commerce, National Institute of Standards and Technology, 2019
URL	http://books.google.com.hk/books?id=nnvRxQEACAAJ&hl=&source=gbs_api

註釋Rotational rheometers are commonly used to measure a material's rheological properties such as viscosity and yield stress [1]. Manufacturers of rheometers generally recommend the use of a standard oil of known viscosity to calibrate the instrument in order to ensure it's proper operation. These oils are Newtonian fluids and are not representative of the flow of concrete, mortar or paste which behave as a Bingham, Hershel-Bulkley, or power-law fluid. Also, oils are expensive, and would be cost prohibitive because large volumes of the reference material would be needed to calibrate concrete rheometers. Therefore, a relatively inexpensive, well characterized reference material, with properties similar to concrete, (e.g., non-Newtonian and contains aggregates similar in dimension to that in concrete for testing in concrete rheometers) is needed. The purpose of this report is to describe the process used to create and certify a new Standard Reference Material, SRM 2497, a "Standard Reference Concrete for Rheological Measurements". The development of this new Standard Reference Material (SRM) is based on a three-step-multi-scale approach. The first step was to develop a paste rheology reference material (SRM2492) [2], the second step involved creating a mortar rheology reference material, SRM2493 [3]. The final step, described in this work, is development of a concrete rheology reference material, SRM 2497. All measurements used for the development of SRM 2497 are provided along with statistical analyses. A brief description, along with references, of the computational model that was utilized to predict the behavior of the SRM is also provided. The data analyzed in this study serves to certify that the proposed models and values are validated with proper quantification of uncertainty