Abstract:
More than seventy percent of the volume of concrete is occupied by aggregates. Aggregates with undesirable qualities will have an adverse effect on durability and structural performance of concrete. Though gneiss is normally used as coarse aggregates in production of concrete, due to their unavailability in the region, limestone is used as coarse aggregate for production of concrete in Northern Sri Lanka, without appropriate investigations.
In this study, impact of limestone aggregates on concrete properties such as slump, initial setting time compressive strength, flexural strength, etc. were investigated under laboratory conditions and the results were compared with the concrete made with normal aggregates. Two types of limestone aggregates were used for this purpose, red limestone which was collected from Walikamam west, Jaffna and white limestone, which was collected from Chavakachcheri area.
It was found that water absorption of limestone aggregates is 50% higher than that of the normal aggregates. Also, workability and compaction ability in limestone concrete are significantly lower for a given w/c ratio compared to normal aggregate concrete. However, compressive strength and flexural strength are found to be the same as the normal aggregates. Also, results indicate that red limestone aggregates have better performance than the white limestone aggregates
