Study of the Characteristics of Kutai Kertanegara Local Quarry Stone for Self-Compacting Concrete Production

Classification, abrasion, and compressive strength conditions of rocks can affect the quality of concrete and potentially cause damage/failure of building structures.This local rock research is needed for utilization as coarse aggregate in concrete mixtures.Rocks are located in 4 quarries in Kutai Kertanegara Regency.Each quarry was identified by taking rocks in the form of boulders and coarse aggregates.Rock samples were observed visually from a geological perspective and tested for physical and mechanical properties.Rock compressive strength test with cube-shaped samples measuring 5 x 5 x 5 cm.The compressive strength value of 50 MPa was continued to make high-quality SCC concrete samples in cylinders measuring 10 x 20 cm for each age of 3, 7, 14, 21, 28, 56, and 90 days.Then, the rock classification was obtained, including limestone, and it had many cracks.The average rock abrasion value was obtained at less than 40%.The compressive strength of the rock at location KM.45 was 64.89 MPa, KM.40 obtained 42.05 MPa, while other places did not meet the minimum value.The 28-day concrete compressive strength was obtained 28.662 MPa from the KM.45 location and 23.884 MPa from the KM.40 location.The development of concrete strength according to age shows a trend that does not increase and fluctuates.Compared to concrete, it generally shows a trend that continues to increase according to age.This condition indicates that the limestone has uneven or inconsistent strength, so it is unsuitable for high-quality concrete use.This information is expected to be a guideline for using local rocks.