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Title: Evaluation of Uniformity of Concrete Properties on Selected Building Construction sites in Addis Ababa
???metadata.dc.contributor.*???: Ephraim Senbetta (PhD)
Sity, Mensur
Keywords: Compressive Strength;Slump;Test;Uniformity;Workability
Issue Date: May-2016
Publisher: AAU
Abstract: In any mixer, it is essential that sufficient interchange of materials between different parts of mixer chamber takes place, so that the uniform concrete is produced. The efficiency of the mixer can be measured by the variability of the mix discharged into a number of cubes without interrupting the flow of concrete. The objective of this research is to evaluating the uniformity of site produced concrete by taking slump tests and compressive strength test on selected sites in Addis Ababa. To meet the above mentioned objective questioner survey and experimental works were conducted. Two hundred (200) questionnaires were distributed; out of these only one hundred thirty four (134) were collected. Field tests were conducted on three selected ongoing building projects. On those sites five (5) slump tests and four (4) compressive strength test samples were conducted from each site. For compressive strength test four samples were taken for 7 days and 28 days. A total of fifteen (15) slump tests and seventy two 150mm cube tests were conducted by taking sample concrete produced in/at the ongoing selected project sites. From the questionnaire survey, most of the respondents agreed the produced concrete properties are sometimes uniform or sometimes not uniform. However, the test results showed that most of the samples are not uniform. Coefficient of variation was used to evaluate the uniformity of concrete produced on selected sites. And results showed that the same grade of concrete produced at different time (day) is significantly inconsistent. There is a significant variation in compressive strength among the same concrete produced at different times.
Appears in Collections:Thesis - Construction Technology Management

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