<![CDATA[Penelitian ini bertujuan untuk mengetahui pengaruh penggunaan abu kerang erosa sebagai bahan tambah terhadap kuat tekan mortar. Variasi penambahan abu kerang erosa dilakukan sebesar 0%, 2,5%, 5%, 7,5%, dan 10% dari berat semen sesuai standar SNI 03-6825-2002. Benda uji berbentuk kubus berukuran 5×5×5 cm diuji kuat tekannya pada umur 7 dan 28 hari. Hasil penelitian menunjukkan bahwa penambahan abu kerang erosa berpengaruh terhadap penurunan kuat tekan mortar. Nilai kuat tekan tertinggi pada umur 7 hari diperoleh pada campuran 0% sebesar 252,02 kg/cm² dan menurun berturut-turut hingga 201,61 kg/cm² pada penambahan 10%. Pola serupa terjadi pada umur 28 hari, di mana kuat tekan tertinggi juga terdapat pada 0% sebesar 262,10 kg/cm² dan menurun hingga 204,76 kg/cm² pada 10%. Meskipun kuat tekan meningkat dari umur 7 hari ke 28 hari, peningkatan tersebut tidak mampu mengimbangi penurunan akibat penambahan abu kerang berlebih. Berdasarkan klasifikasi SNI 03-6882-2002, campuran 0%, 2,5%, 5%, dan 7,5% tergolong mortar tipe M, sedangkan 10% termasuk tipe S. Dengan demikian, abu kerang erosa masih dapat dimanfaatkan sebagai bahan substitusi sebagian semen, namun penggunaannya perlu dibatasi agar tidak menurunkan kekuatan mortar secara signifikan. This study aims to determine the effect of using erosa shell ash as an additive on the compressive strength of mortar. Variations in the addition of erosa shell ash were carried out at 0%, 2.5%, 5%, 7.5%, and 10% of the weight of cement according to the SNI 03-6825-2002 standard. Cube-shaped test specimens measuring 5×5×5 cm were tested for their compressive strength at the age of 7 and 28 days. The results showed that the addition of erosa shell ash had an effect on reducing the compressive strength of the mortar. The highest compressive strength value at the age of 7 days was obtained at a mixture of 0% at 252.02 kg/cm² and decreased successively to 201.61 kg/cm² at an addition of 10%. A similar pattern occurred at the age of 28 days, where the highest compressive strength was also found at 0% at 262.10 kg/cm² and decreased to 204.76 kg/cm² at 10%. Although the compressive strength increased from 7 days to 28 days, the increase was not able to compensate for the decrease due to the addition of excessive shell ash. Based on the SNI 03-6882-2002 classification, a mixture of 0%, 2.5%, 5%, and 7.5% is classified as type M mortar, while 10% is included in type S. Thus, erosa shell ash can still be used as a partial cement substitute, but its use needs to be limited so as not to reduce the mortar strength significantly.]]>
