Author: W. L. Frederick
Publisher:
ISBN:
Category : Aggregates (Building materials)
Languages : en
Pages : 39

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Author: P. Xie
Publisher:
ISBN:
Category : Blast-furnace slag
Languages : en
Pages : 5

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Author: RD. Hooton
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 6

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Book Description
Some agencies limit the slag (ground-granulated blast-furnace slag) replacement of portland cement in some instances. In other cases, minimum slag replacements are specified. Therefore, there is a need to be able to quantify the slag content to show conformance with specifications. The two methods proposed here are (1) X-ray diffraction (XRD) of ignited mixtures and (2) optical microscopy on thin sections. The XRD method involves ignition of the mortar fraction of concrete at 950 to 1050°C to devitrify the unreacted slag. The resulting crystalline melilite component is then compared to that in an ignited sample of slag from the same source.

Author: Gerardo G. Clemeña
Publisher:
ISBN:
Category : Cement
Languages : en
Pages : 38

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The method of selective solution by methanolic maleic acid, developed by Tabikh et. al for the determination of cement content in hardened concrete, was evaluated. It was found to be relatively simple and inexpensive, and is accurate to within ±1 percentage point cement at the 95% confidence level with the use of calibration curves. Such factors as aggregate and cement compositions, curing time, and water-cement ratio were investigated as to their effects on the method. Among these factors, aggregate composition was the only one found to have a significant effect on the analytical results. The determination of cement content by the measurement of the specific gravity increase in a methanolic maleic acid solution was also investigated, but was found to have unsatisfactory precision.

Author: MG. Grantham
Publisher:
ISBN:
Category : Admixtures
Languages : en
Pages : 3

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Book Description
The paper briefly reviews the standard United Kingdom (UK) procedure for the determination of cement content of hardened concrete. It then points out the special problems that occur when attempting to determine the cement content and the amount of mineral admixture in concrete. The method described in this paper, originally devised by the Building Research Establishment, employs a total analysis of the concrete and control samples of the cement, aggregates, and mineral admixture. The method usually used is quantitative X-ray fluorescence (XRF) analysis. The analytical results are examined by the application of a simultaneous equation mathematical approach to resolve the content of the individual components. Application of the method in a case history is used for illustration.

Author: Alvin Davis
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: L. J. Minnick
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 14

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Book Description
Determination of the portland cement content of hardened concrete is often a matter of concern to engineers and chemists working with mortars and concretes. Unfortunately, a precise method of analysis has not been developed due to the many complexities of the material under test. Difficulties include the selection of representative samples, the presence of aggregate materials from unknown sources, the use of portland cements that differ substantially from an average composition, the presence of admixtures or additions (such as pozzolans or finely ground slag), the degree of hydration of the cement, the effect of carbonation as contrasted with hydration, and the effect of leaching of the concrete. In view of such formidable obstacles, chemical procedures demand that every effort should be made to obtain samples of the materials used in the concrete mixture. Where adequate information is obtained on the coarase and fine aggregate and cementing material, a reasonably accurate estimate of the cement content of hardened concrete can be made by chemical methods. In the absence of sufficient information on the source materials, assumptions must be made with respect to the amount of soluble substances that may be contributed to the analysis by the aggregate fractions and with respect to the ratio of aggregate materials present in the mixture. The assumptions affect the reliability of the test results. In some instances, the use of several schemes of analysis should be considered since the information derived from one method may assist in interpreting the results derived from an alternate method. This report outlines several methods that have been employed to determine the cement content of hardened concrete and indicates the reliability of the results that have been obtained, with emphasis being given to the procedure that is available as ASTM Test for Cement Content of Hardened Portland Cement Concrete (C 85). Results of cooperative tests undertaken by ASTM Committee C-9 to evaluate the reliability of the ASTM method of test are presented.

Author: Nele De Belie
Publisher: Springer
ISBN: 3319706063
Category : Technology & Engineering
Languages : en
Pages : 336

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Book Description
This volume represents the current knowledge on the effect of SCMs (slag, fly ash, silica fume, limestone powder, metakaolin, natural pozzolans, rice husk ash, special SCMs, ternary blends) on the properties of fresh and hardened concrete (e.g. early strength development, workability, shrinkage) and curing requirements. Other topics treated in the book are postblending vs preblending, implications of SCM variability, interaction between SCM and commonly used admixtures (e.g. superplasticizers, air entrainers).

Author: Charles L. Ford
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 68

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Author:
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 4

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