TY - JOUR AU - Harahap, Mukti Hamjah AU - Putri, Aulia E. PY - 2020/12/22 Y2 - 2024/03/29 TI - Effect of variations in the composition and size of red sand grains on the quality of K-225 concrete JF - Journal of Metals, Materials and Minerals JA - J Met Mater Miner VL - 30 IS - 4 SE - Original Research Articles DO - 10.55713/jmmm.v30i4.765 UR - https://jmmm.material.chula.ac.th/index.php/jmmm/article/view/765 SP - 79-83 AB - <p>The effect of variations in the composition and size of red sand grains on the solid quality made in the form of a 15×15×15 cm cubes were investigated. By implementing the standard of SNI K-225  which is a mixture of 1:1.9:2.8 with FAS 0.6 and the composition of red sand consisting of 0, 2, 4, 5, and 6.5% of the weight of fine aggregate and variations in the size of red sand grains of 80, 100, and 120 mesh, the concrete was being treated in a water bath for 28 days. It was tested by the method of water absorption, compressive strength test, Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD). The test result of SEM indicated that variations of both the composition and size of red sand grains affect the porosity of the concrete. XRD test obtained Ca(OH)<sub>2</sub>, CaCO<sub>3</sub> and SiO<sub>2</sub>, as the highest intensity element, and the similar crystal structure formed is hexagonal. The maximum compressive strength of the concrete on the composition of 4% with a grain size of 80 mesh red sand that is 32.3 MPa with  is linear with the results of testing the water absorption of concrete along with the decreasing variations in the size of red sand grain.</p> ER -