STM Article Repository

Concrete is a mixture of cement, fine aggregate, coarse aggregate, and water with or without additional ingredients to form a solid mass, its use is very common in building structures, but the final quality of the strength of the concrete depends on many factors, including the implementation of its manufacture. and immersion. The research aimed to determine changes in the quality of k-300 concrete and the maximum strength of concrete immersed in salt water. The research was carried out in the Laboratory of the Faculty of Engineering, University of 17 August 1945 Samarinda for 2 months. The stages of research activities are starting, literature study, preparation of materials and tools, testing concrete building materials in the laboratory, designing concrete mixes, making test objects/samples, evaluation, testing concrete compressive strength, conclusions, and reporting. Tests carried out in the laboratory include: (1) checking wear/abrasion of coarse aggregate using the Los Angeles method; (2) examination of coarse aggregate and fine aggregate sieve analysis; (3) examination of specific gravity and SSD absorption of coarse aggregate and fine aggregate; (4) checking water content; (5) checking mud and clay levels; (6) checking the bulk density of coarse aggregate, fine aggregate and mixed aggregate; (7) inspection of concrete slump experiments; (8) soaking concrete using seawater and freshwater; and (9) checking concrete compression strength. The research results show that: (1) The compressive strength of K-300 concrete soaked in seawater, namely 304,915 f'c, is lower than that soaked in fresh water, namely 308,580 f'c; and (2) differences in concrete compressive strength occur at old concrete ages (21 days and 28 days) but at young concrete ages (3, 7 and 14 days) there are no differences in compressive strength.