Volume 1 , Issue 1 , January 2016 , Pages 110-120
1 Department of Geology, College of science, Salahaddin University, Erbil-Iraq
Limestone of Shiranish and Pila Spi formations were evaluated as concrete
aggregates through this study. For this purpose two outcrops had been selected; the first
outcrop is Pila Spi Formation at Pirmam Anticline, and the second outcrop is Shiranish
Formation at Safin Anticline. Both outcrops are located in the High Folded Zone,
between Erbil and Shaqlawa cities. Chemical analysis for the studied samples shows that
the limestone of Shiranish Formation has more calcite proportion, while the limestone of Pila Spi Formation is
dolomitic. This was supported by the X-ray analysis and staining process by Alizarin
Red S. To assess the studied limestone for concrete aggregate, the samples have been
crushed and sieved into two grades, 4-30 mm (coarse aggregate) and finer than 4 mm
(fine aggregate). The coarse portion is used instead of pebble and the fine portion is used
instead of sand in concrete mixture. Eight briquettes with dimensions of 15 cm3
for each sample were formed. Two ratios of cement: fine aggregates: coarse aggregates were
tested; 1: 1.5: 3 and 1: 2: 4 respectively. These raw materials were mixed with water in
two ratios; 1:0.5 and 1: 0.75 for cement: water ratio respectively.
The compressive strength tests show that the concrete prepared from Shiranish
limestone aggregate give best results when compared with that prepared from Pila Spi
limestone aggregate. These results proved that the Pila Spi limestone is suitable for using
as aggregate in manufacturing concrete masonry only after twenty eight days of soaking
in water. While Shiranish limestone is suitable for using as an aggregate in
manufacturing concrete masonry after seven and twenty eight days soaking in water, as
well as aggregate in manufacturing concrete foundation, column and roof after twenty
eight days soaking in water. In addition to that, other concrete briquettes were formed
from both formations, after soaking the limestone aggregates in water for 24 hours and
showed bad results in the term of consistency.