Effect Of Using Basalt And Limestone As Coarse Aggregate In Concrete Mixtures

ABSTRACT

In this study, concrete mixtures were tested to effect of basalt and limestone as coarse aggregate and evaluate their efficiency on fresh and hardened concrete to achieve the design compressive strengths of [25N/mm2]. By using different proportions is 25%, 50%, 75% and100 %from the weight of coarse aggregate. The study was carried out for 6 types of concrete mixes designed by British Standard, compressive strength of concrete and workability were measured in the reconstruction of maturing for ( 7, 28 and 56) days. One of those concrete mixes is a design mix in order to determine the optimum ratio can be added to concrete to obtain design compressive and increase with time. All the results were compared with the Design Mix. The study shown the effect of basalt and limestone on workability of fresh concrete by decreasing with the proportion of basalt and limestone ,also for the hardened concrete the specific compressive strength not less than[25N/mm2] at 28 days of curing , It was also found that the ideal ratio for high compressive strength is the use of basalt (100%) , this ratio over the mix design about (27% in 7days & 11% in 28 days and 11.5% in 56 days of curing) and the second ratio is the use of basalt (75% ) with limestone (25%) , these ratio decreases with increasing limestone, this is due to the fact that basalt is denser and more durable and less water absorbing than limestone.