Comparison of Concrete Properties Produced Using Mugher, Messebo and Diredawa Cements.
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Date
2005-11
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Addis Ababa University
Abstract
Properties of concrete and its constituent materials are theoretically explained. The three cement
factories across the country were visited and test results of Mugher OPC and PPC, Messebo OPC
and PPC and Diredawa PPC were collected from their respective factories. Then the chemical
and physical properties of these cements were analyzed. Furthermore, three mix proportions for
Normal, Intermediate and High Strength Concretes were conducted in laboratory. At each mix
proportion there are five mixes which were made keeping every condition the same but varying
the cement types.
To see the effect of curing on strength development among concretes made of the five cement
types, different curing conditions were applied.
The analyzed cement test results together with literature survey on effect of cement in concrete
properties are used to propose and compare concrete strength and other properties among the
concretes made of the five cements. The laboratory conducted compressive strength test results
are also used to compare the rate of strength development, the difference in compressive strength
values with age and to see the effect of curing on compressive strength development.
In each class of concrete, concreting was made keeping every condition the same except varying
the cement type; hence, the variation on the concrete properties is mainly attributable to the
cement’s properties.
As shown on the analysis part, the expected concrete strength proposed using the cement test
results analysis has turned out to be similar with the laboratory compressive strength test results.
In fact, this has created strong confidence with regard to the other concrete properties proposed
using the cement test results analysis.
Observation on the test results of this research indicates that for the mix proportions and curing
conditions made in this study, at all ages and classes of concrete, Messebo OPC has produced the
highest compressive strength concrete, followed by Mugher OPC, Messebo PPC, Mugher PPC
and Diredawa PPC in descending order. Besides, though the compressive strength differences
between the concretes made of the PPCs and OPCs show a decreasing trend with age, the gap in
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strength at the age of 91 days between them is too large to be narrowed and matched with time.
Therefore, the PPCs can not produce a concrete strength as high as that of the OPCs.
The low pozzolanicity of the volcanic pozzolanas used in production of the three PPCs as well as
shortage of extended moist curing are the reasons believed to make the ultimate strength of
concretes made of the PPCs to be lower than that of the OPCs’ at the age of three months.
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Keywords
Diredawa Cements