Author
Eng. Abdirahman Ismail Dhaqane, Dean, Faculty of Engineering, Mogadishu University University
COMPARATIVE STUDY BETWEEN NATURAL AND ARTIFICIAL AGGREGATES (A Experimental study of Quality of Artificial and natural Aggregates Used for Construction in Mogadishu City)
Abstract
The utilization of two types of aggregate for concrete work is investigated in this paper. Concrete is being produced from different types of aggregate and this imparts different property to the resulting concrete. The most important property of concrete is its compressive strength.
The purpose of this work, two types of coarse aggregates, crashed (Artificial) and natural aggregates were used. At beginning, the laboratory investigation was conducted to determine the suitability of using the aggregates for construction work. Tests conducted include sieve analysis, bulk density, specific gravity and absorption capacity. For each type of coarse aggregate 6 cubes (150x150mm) were cast to allow the compressive strength to be monitored at 7, 21, and 28 days.
The highest compressive strength was obtained from concrete made with crushed (Artificial) aggregate, followed by Natural Aggregate. The void ratio is to be found in range of 25% to 32%, which is enough for
pervious concrete. The Fineness modulus of natural aggregates in the three samples is 6.9, 6.5, 6.9 and the average number is 6.8. The result shown the fineness modulus of sample-2 is below the average and the sample-1 is above the average. The value of specific gravity of crashed aggregate is 2.56 and natural aggregates are 3.14 respectively. The specific gravity of aggregates normally used in road construction ranges from about 2.5 to 3.0.
Test result show that concrete made from natural the highest workability followed by crushed (Artificial) and aggregates. The result shows the highest slump was obtained with concrete made with both natural and crashed aggregate with 0.8 w/c ratio by improper compaction.Both aggregates are recommended to use 0.5 w/c ratio with proper compaction to get minimum slump hight and true slupm It is suggested that crushed (Artificial) aggregate may be working for concrete work in places where concrete practitioners have selection of choices available.
