Pengaruh Variasi Faktor Air Semen (FAS) Terhadap Karakteristik Paving block Dengan Pemanfaatan Lumpur Aktif Dari Unit Aerasi IPAL

Abstract

Akumulasi lumpur pada Instalasi Pengolahan Air Limbah (IPAL) dan tingginya ketergantungan produksi paving block terhadap pasir alam mendorong upaya pemanfaatan lumpur aktif sebagai substitusi parsial agregat halus. Faktor air semen (FAS) menjadi parameter kritis karena lumpur aktif bersifat berpori dan menyerap air. Penelitian ini bertujuan menganalisis pengaruh variasi FAS dan persentase substitusi lumpur terhadap kuat tekan dan daya serap air paving block serta mengevaluasi pemenuhannya terhadap SNI 03-0691-1996. Rancangan faktorial 3×3 diterapkan dengan variasi FAS 0,60; 0,70; dan 0,80 serta substitusi lumpur 0%, 10%, dan 20%, mencakup 54 benda uji pada umur perawatan 28 hari. Hasil menunjukkan substitusi lumpur secara konsisten menurunkan kuat tekan dan meningkatkan daya serap air; benda uji substitusi 20% pada FAS 0,60 dan 0,70 kehilangan integritas saat pengeringan. Pengaruh FAS terhadap kuat tekan bersifat kondisional terhadap kehadiran lumpur, sedangkan daya serap membentuk pola U dengan nilai terendah pada FAS 0,70. Kinerja terbaik dicapai komposisi kontrol FAS 0,60 tanpa lumpur (Mutu C).

The accumulation of sludge in wastewater treatment plants (WWTP) and the strong dependence of paving block production on natural sand have motivated using activated sludge as a partial fine aggregate substitute. The water-cement ratio (WCR) is a critical parameter because activated sludge is porous and highly absorptive. This study aimed to analyze the effect of WCR variation and sludge substitution percentage on the compressive strength and water absorption of paving blocks and to evaluate their compliance with SNI 03-0691-1996. A 3×3 factorial design was applied, varying WCR at 0.60, 0.70, and 0.80 and sludge substitution at 0%, 10%, and 20%, comprising 54 specimens cured for 28 days. The results showed that sludge substitution consistently reduced compressive strength and increased water absorption; specimens with 20% substitution at WCR 0.60 and 0.70 lost integrity during drying. The effect of WCR on compressive strength was conditional on the presence of sludge, while water absorption formed a U-shaped pattern with the lowest value at WCR 0.70. The best performance was achieved by the control mix at WCR 0.60 without sludge (Quality C).