Budiman, Adi Drajad (2026) Pemanfaatan Limbah Sludge Desalinasi dan Iron Silicate PT Freeport Smelter Gresik Sebagai Prekursor Sintesis Agregat Buatan pada Beton. Other thesis, Institut Teknologi Sepuluh Nopember.
![[thumbnail of 5012221017-Undergraduate_Thesis.pdf]](http://repository.its.ac.id/style/images/fileicons/text.png) |
Text
5012221017-Undergraduate_Thesis.pdf - Accepted Version Restricted to Repository staff only Download (9MB) | Request a copy |
Abstract
Sludge desalinasi (SD) dan iron silicate (IS) merupakan limbah PT Freeport Smelter Gresik yang belum pernah dimanfaatkan, dengan akumulasi mencapai 400 ton dan 127.000 ton per bulan, dan berpotensi mencemari lingkungan melalui kandungan klorida, logam berat, serta padatan terlarut yang tinggi. Material tersebut mengandung komponen aluminosilikat dan besi yang membuka peluang valorisasi sebagai prekursor agregat buatan sintering. Penelitian ini dirancang dalam tiga tahap: sintesis agregat dengan variasi rasio SD, optimasi lanjutan melalui IS menggunakan pendekatan MCDM-TOPSIS, serta aplikasi dua formula terpilih sebagai substitusi agregat kasar beton pada kadar 5-25%. Hasil karakterisasi menunjukkan SD didominasi SiO2, Al2O, dan Fe2O3, memenuhi syarat material sinter berkualitas baik. Pembakaran menurunkan klorida dan menginduksi transformasi mineralogi yang meningkatkan kelayakan SD sebagai bahan konstruksi. Berdasarkan evaluasi MCDM-TOPSIS, formulasi optimum yang ditetapkan adalah SD pada tahap pertama dan IS pada tahap optimasi. Penambahan iron silicate meningkatkan kuat tekan agregat, menurunkan penyerapan air, dengan nilai abrasi yang memenuhi standar kelayakan agregat kasar. Pada aplikasi beton, substitusi 5-25% mempertahankan workability pada rentang 180-260 mm. Beton SD mencapai kuat tekan 28 hari tertinggi pada substitusi 5%, yang dikaitkan dengan mekanisme internal curing dan pembentukan C-S-H yang memperbaiki densifikasi ITZ. Beton IS menunjukkan kuat tekan yang konsisten pada rentang 64,16-65,12 MPa hingga substitusi 25%. Seluruh variasi tergolong beton mutu tinggi, dengan konfirmasi internal curing melalui pergeseran waktu temperatur puncak hidrasi dan perpanjangan durasi pendinginan. Penelitian ini membuktikan bahwa valorisasi simultan SD dan IS sebagai agregat buatan layak secara teknis dan mampu menghadirkan nilai fungsional yang melampaui agregat alam konvensional.
=====================================================================================================================================
Desalination sludge (DS) and iron silicate (IS) are industrial by-products from PT Freeport Smelter Gresik that have not yet been utilized, with monthly accumulations reaching approximately 400 tons and 127,000 tons, respectively. These wastes pose environmental hazards due to high contents of chlorides, heavy metals, and dissolved solids. The materials contain aluminosilicate and iron components, offering opportunities for valorization as precursors for sintered artificial aggregates. This study was designed in three stages: synthesis of aggregates with varying DS ratios, further optimization through IS incorporation using a MCDM-TOPSIS approach, and application of the two selected formulations as partial replacements for coarse concrete aggregates at 5–25% substitution. Characterization showed DS is dominated by SiO₂, Al₂O₃, and Fe₂O₃, satisfying criteria for high-quality sintering material. Thermal treatment reduced chloride content and induced mineralogical transformations, enhancing DS suitability as a construction material. Based on MCDMTOPSIS evaluation, the optimum formulations were identified as DS in the initial stage and IS during optimization. Addition of iron silicate increased aggregate compressive strength, reduced water absorption, and produced abrasion values meeting coarse aggregate standards. In concrete applications, 5–25% substitution maintained workability between 180–260 mm. Concrete incorporating DS achieved the highest 28-day compressive strength at 5%, due to internal curing and C-S-H formation improving ITZ densification. Concrete with IS exhibited consistent 28-day compressive strength of 64.16–65.12 MPa up to 25% substitution. All mixtures qualified as high-performance concrete, with internal curing confirmed by shifts in peak hydration temperature and extended cooling. Overall, this study demonstrates that simultaneous valorization of DS and IS as artificial aggregates is technically feasible and provides functional performance exceeding conventional natural aggregates.
Actions (login required)
 |
View Item |