The Proficiency of Sand Equivalent and Methylene Blue (Clay Index) Test Methods for Determining the Deleterious Mineral Content of Weakly Metamorphosed Sedimentary Rock

Show simple item record Lowe, JS en Wilson, Douglas en Black, Philippa en 2012-04-03T21:07:08Z en 2010 en
dc.identifier.citation Road and Transport Research 19(4):23-36 2010 en
dc.identifier.issn 1037-5783 en
dc.identifier.uri en
dc.description.abstract Weakly metamorphosed sedimentary rocks have the potential to contain levels of deleterious minerals that can have a negative impact on aggregate properties. Two of the most frequently employed methods to determine the cleanliness and therefore ensure suitability for use of fine aggregates and sands are the sand equivalent and methylene blue tests. Values relating to these test methods are often adopted in specifications as pass/fail criteria for establishing the suitability of an aggregate. This approach means many aggregate sources are precluded from use, and so a primary aim of this research is to highlight what potential effect this approach has on maximising the utilisation of nonrenewable aggregate resources. The importance of the quality of aggregate fines and some of the specific deleterious minerals of concern are discussed in the context of New Zealand mineralogy (although the findings are relevant to countries with similar weakly metamorphosed sedimentary rocks). The methodology of both test methods and some of the limitations and concerns are also discussed. The paper outlines the experimental program and testing that took place over a period of three months. The results presented and discussed for 380 samples from seven quarries aimed at trying to establish a correlation between the sand equivalent and the clay index. In agreement with previous research it was concluded that no correlation between the two test methods exists (R2 = 0.08). Possible reasons for a lack of correlation are presented, along with the concepts of a new ‘normalised’ clay index and a ‘steady state’ sand equivalent. Early results from an initial testing program are presented which demonstrate that the adapted testing methodology gives a stronger correlation (R2 = 0.65) between the two test methods and has the potential to give a better indication of an aggregate’s suitability for use. en
dc.publisher ARRB Group en
dc.relation.ispartofseries Road and Transport Research en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obtained from: en
dc.rights.uri en
dc.title The Proficiency of Sand Equivalent and Methylene Blue (Clay Index) Test Methods for Determining the Deleterious Mineral Content of Weakly Metamorphosed Sedimentary Rock en
dc.type Journal Article en
pubs.issue 4 en
pubs.begin-page 23 en
pubs.volume 19 en
dc.rights.holder Copyright: ARRB Group en;res=IELENG;search=FTI=yes%20and%20IS=1037-5783%20and%20VRF=19%20and%20IRF=4%20and%20PY=2010%20and%20PG=23 en
pubs.end-page 36 en
dc.rights.accessrights en
pubs.subtype Article en
pubs.elements-id 194972 en Engineering en Civil and Environmental Eng en
pubs.record-created-at-source-date 2010-12-08 en

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