Effect of Clayey Silt Content on Concrete Stregth
No Thumbnail Available
Date
2014-03
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
In the present day construction industry in Ethiopia, concrete has emerged as the most common building material. Hence careful consideration must be given to factors that affect its strength. One of the factors affecting the strength of concrete is the amount of clayey silt content of sand used in the mix of concrete. This work (thesis) determines the strength of concrete (compressive, tensile using splitting method and flexural strength) for sand samples with varying percentage of clayey silt content from 0% to 10% for C-25 mix design and the principal aim of this research is to investigate the effects of clayey silt microfine coatings of sand on concrete structures and to use this knowledge to improve the present aggregate monitoring situation in Ethiopia. From the mix design the proportion of materials for concrete is found to be 1:2:4 ratios. The sand sample was collected from a quarry site at Senbo River located in the National States of Oromia, Horu Gudru Welega Zone around Fincha Sugar Factory. The silt content of the quarry sand was tested and found to be 5.05%. The sand sample was divided into five parts (A-E) and in such a way that from each part, 3 cubes (of 150 x 150 x 150 mm3) each for 3, 7 and 28 days of curing time for compressive strength, 2 cylinder (Ф=150mm and h=300mm) for 7 and 3 cylinders ( of the same dimension) for 28 days of curing time for tensile strength and 2 prism (100*100*510mm3) for 28 days of curing time for flexural strength test was prepared. For 0% silt all of the sand was washed. For 2.5% half of the sand was washed. For 5.05% the quarry sand is used. For 7.5% and 10% the additional silt/clay required was collected from the quarry sand using 75μm sieve so that the required amount 2.45% and 4.95% by weight respectively for each samples were added. The resultant samples of mixture of washed sand and with clay/silt were labeled samples A to E. Sample A contained 0% clay/silt; sample B contained 2.5% of clay/silt and so on. The compressive strength, tensile strength and flexural strength of concrete of each part of sand with varying content of clay/silt from 2.5% to 10% were determined. From the laboratory test result it was discovered that the higher the silt/clay content of sand in the concrete mix, the weaker is the strength of the concrete.
Description
Keywords
Structural Engineering