Abstract:
Aggregates constitute the bulk of the total volume of concrete and hence influence the
strength of concrete to great extent. It is essential that aggregates used in construction
purposes are strong and durable. Construction aggregate is crushed rock material used
in concrete which make up most of engineering works. The main objective of this
research was to assess the quality of coarse aggregates and evaluate their suitability for
concrete of the limestone rock material sources in Mekelle area, northern Ethiopia. As
there was no previous studies on the quality of aggregates in Mekelle this research was
designed to better understand the properties and qualities of aggregates used in the
project area. The study involved assessment of the different sources of rocks for concrete
aggregates, collecting representative samples and laboratory analysis. The study mainly
focused on 20-30km radius from Mekelle city and 10 representative quarry sites were
analyzed. The properties used to assess the suitability of rocks as aggregate materials
include tests like: Los Angeles Abrasion (LAA), Aggregate crushed value (ACV), sieve
analysis, flakiness index, moisture content, unit weight, specific gravity and water
absorption. Results of the analysis show that the ACV of aggregate varies between 5.9%
and 19.7%, the LAA value ranges from 24.94% to 33.62%, the water absorption ranges
from 0.34% to 0.76%, and the moisture content falls below one percent. All the test result
shows that the aggregate fulfill the ASTM standard requirement except moisture content
is below the minimum ASTM requirement. This research has given a better
understanding of the quality and suitability of rock material used for concrete in Mekelle
area, Ethiopia.
