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Water Reducing and Retarding Admixture Effect on the Mechanical Properties of Ready Mixed Concrete

Yordanose Mogse


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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:creator>Yordanose Mogse</dc:creator>
  <dc:date>2018-10-25</dc:date>
  <dc:description>Concrete can be produced with a better quality by the addition of Water Reducing and Retarding
(WRR) admixture in different ways by saving mixing water and cement content from a given mix
design. This study investigated the effects of WRR admixture on ready mixed concrete properties
viz: workability, compressive strength and permeability. To achieve the objective experiments
were conducted on C-25 and C-40 concrete grades with 0.49 and 0.30 water to cement ratio
respectively by a slump of 160-220mm, at a dosage of 0% (control), 0.5%, 0.85% and 1.2%
admixture. To facilitate the study, the experiments have been done in four stages, namely: Stage I:
to study the effects of WRR admixture on concrete workability, Stage II: to study the effects of
WRR admixture at optimum dosage of workability on concrete compressive strength, Stage III: to
study the effects of WRR admixture on compressive strength by reducing cement content in 5%,
8% and 12% and Stage IV: to study the effects of WRR admixture on concrete compressive and
permeability test by reducing amount of mixing water at constant slump. Based on the
experimental results 0.85% and 1.2% WRR admixture dosage were found to have higher value of
workability for C-25 and C-40 concrete grade respectively. At optimum dosage of 0.85% WRR
admixture, the compressive strength of C-25 has shown improvement over that of the control mix
whereas, the 1.2% WRR admixture slightly reduced the compressive strength of C-40 over the
control mix. Further optimum results on concrete compressive strength was found at 8% cement
reduced concrete with the addition of 0.85% and 1.2% WRR admixture for C-25 and C-40
concrete grade respectively. Total CO2 emission and total cost was reduced from the control mix
by optimum cement reduced and WRR admixture added concrete for C-25 and C-40. On the other
hand, optimum result on C-25 compressive strength and permeability was found in the addition of
1.2% WRR admixture by 11.32% mixing water reduction. It can therefore be concluded that the
addition of WRR admixture was shown improvement on workability, compressive strength and
permeability from the control mix. It is recommended that ready mixed concrete manufacturer
should be used at 0.85% and 1.2% WRR admixture dose for C-25 and C-40 concrete respectively.</dc:description>
  <dc:identifier>https://nadre.ethernet.edu.et/record/20234</dc:identifier>
  <dc:identifier>10.20372/nadre/20234</dc:identifier>
  <dc:language>eng</dc:language>
  <dc:relation>doi:10.20372/nadre/20233</dc:relation>
  <dc:relation>url:https://nadre.ethernet.edu.et/communities/aastu</dc:relation>
  <dc:relation>url:https://nadre.ethernet.edu.et/communities/nadre</dc:relation>
  <dc:rights>info:eu-repo/semantics/openAccess</dc:rights>
  <dc:rights>http://www.opendefinition.org/licenses/cc-by</dc:rights>
  <dc:subject>Concrete, WRR, Admixture, Compressive Strength, Workability and Permeability</dc:subject>
  <dc:title>Water Reducing and Retarding Admixture Effect on the Mechanical Properties of Ready Mixed Concrete</dc:title>
  <dc:type>info:eu-repo/semantics/doctoralThesis</dc:type>
  <dc:type>publication-thesis</dc:type>
</oai_dc:dc>
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