Pemanfaatan Rejected Coal sebagai Substitusi Agregat Halus dan Pengaruh Foam terhadap Sifat Fisis Mekanis Roster

Abstract

Limbah pencucian batubara (rejected coal) berpotensi menimbulkan permasalahan lingkungan karena belum dimanfaatkan secara optimal. Penelitian ini bertujuan memanfaatkan rejected coal sebagai substitusi agregat halus pada beton roster serta mengevaluasi pengaruh penambahan agent foam terhadap sifat fisis dan mekanis material. Metode penelitian meliputi karakterisasi rejected coal menggunakan EDS, XRD dan sudut kontak, formulasi beton roster dengan variasi agregat dan kadar agent foam sebesar 1%, 2%, dan 3% terhadap air serta pengujian sifat fisis dan mekanis setelah curing selama 28 hari. Hasil penelitian menunjukkan penggunaan rejected coal menghasilkan bata beton roster dengan ukuran pori 4,00-4,75 µm, densitas 1,68 gr/cm3 dan penyerapan air 16,88%, serta memiliki nilai kinerja mekanis uji kuat tekan 2,35±0,30 MPa, uji kuat lekat 0,198±0,018 MPa dan uji kuat lentur 1,46 MPa yang sesuai dengan aplikasi konstruksi non struktural. Penggunaan rejected coal dan penambahan agent foam berperan terhadap bobot material serta karakteristik fisis bata beton roster tanpa menurunkan kinerja mekanis.

Coal washing waste (rejected coal) has the potential to cause environmental problems because it has not been optimally utilized. This study aims to utilize rejected coal as a substitute for fine aggregate in roster concrete and to evaluate the effect of adding foam agent on the physical and mechanical properties of material. The research methods included characterizing rejected coal using EDS, XRD, and contact angle, formulation roster concrete with variations in aggregate and foam agent content (1%, 2%, and 3% by weight of water), and testing after 28 days of curing. The results showed the use of rejected coal produced roster concrete bricks with a pore size of 4,00-4,75 µm, a density of 1,68 gr/cm3, and water absorption of 16,88%, as well as mechanical performance values of 2,35 MPa in the compressive strength test, bond strength of 0,199 MPa, and flexural strength of 1,46 MPa, which are suitable for nonstructural construction applications. The use of rejected coal and the addition of a foaming agent affect the weight of the material and the physical characteristics of concrete roster bricks without reducing their mechanical performance.