LEADER 04095aam 2200445I 450 001 9910711167403321 005 20160926090654.0 024 8 $aGOVPUB-C13-91cd240583b853810c5023950d90dc43 035 $a(CKB)5470000002480335 035 $a(OCoLC)958885884 035 $a(EXLCZ)995470000002480335 100 $a20160921d2015 ua 0 101 0 $aeng 181 $2rdacontent 182 $2rdamedia 183 $2rdacarrier 200 10$aRe-certification of SRM 2492 $eBingham Paste Mixture for rheological measurements /$fAlex Olivas; Chiara F. Ferraris; William F. Guthrie; Blaza Toman 210 1$aGaithersburg, MD :$cU.S. Dept. of Commerce, National Institute of Standards and Technology,$d2015. 215 $a1 online resource (121 pages) $cillustrations (color) 225 1 $aNIST special publication ;$v260-182 300 $aAugust 2015. 300 $aContributed record: Metadata reviewed, not verified. Some fields updated by batch processes. 300 $aTitle from PDF title page (viewed August 30, 2015). 320 $aIncludes bibliographical references. 330 3 $aRheological measurements are often performed using a rotational rheometer. In this type of rheometer, the tested fluid is sheared between two surfaces, one of which is rotating [1]. Usually, an angular velocity is imposed on the fluid (through the rotating surface) and this angular velocity determines the shear rate the fluid is subjected to.^The response of the material is monitored by the measurement of the resultant torque on the shaft of the rheometer; this torque can then be converted to shear stress.^In order to calibrate a rheometer, a standard oil of known viscosity should be tested in the rheometer to verify that the instrument is operating correctly.^However, these standard oils are expensive; which makes it impractical for use in calibrating with the rheometer with a large capacity as needed for concrete.^Additional, these standard oils that are not suspensions (i.e.^they do not have solid particles suspended in the media), and thus using them may not capture some issues that may occur in a suspension rheology. Therefore, a relatively inexpensive, reference material is needed that incorporates aggregates for concrete rheometers. As concrete and mortar are non-Newtonian, the reference material should also be non-Newtonian.^This report follows the development and serves as re-certification of a Standard Reference Material (SRM) for cement paste [2].^A multiscale approach will be utilized to develop SRMs for mortar and concrete in the future.^The SRM 2492 will be the matrix fluid for a mortar SRM that will in turn become the matrix fluid for a concrete SRM.^The report SP 260-174 Rev.2012 [2] describes how this SRM 2492, a Bingham Paste Mixture for Rheological Measurements was developed and provides all the details on the various ingredients.^After an inter-laboratory study under the sponsorship of the American Concrete Institute (ACI) committee 238, Workability of Fresh Concrete, it was found that the instructions provided to prepare the SRM were inadequate to obtain reproducible data in all laboratories. Thus after establishing a better preparation method, new instructions were drafted and it was found that the certified values were no longer valid.^Thus, it was necessary to redo a series of testing to obtain a new certified value.^This report provides all measurements obtained, the calculation of the new rheological characteristics and the statistical analyses. 517 $aRe-certification of SRM 2492 700 $aOlivas$b Alex$01401513 701 $aFerraris$b Chiara F$01393227 701 $aGuthrie$b William F$01400236 701 $aOlivas$b Alex$01401513 701 $aToman$b Blaza$01401514 712 02$aNational Institute of Standards and Technology (U.S.).$bEngineering Laboratory.$bInformation Technology Laboratory. 801 0$bNBS 801 1$bNBS 801 2$bGPO 801 2$bNBS 906 $aBOOK 912 $a9910711167403321 996 $aRe-certification of SRM 2492$93470321 997 $aUNINA