Analisis Pengaruh Variasi Resin Epoxy dan Fly Ash 5% sebagai Substitusi Semen terhadap Kuat Tekan Awal dan Setting Time Polymer Cement Concrete

Oleh :
Ezra Clemanta Barus - I0122062 - Fak. Teknik

Perkembangan dunia konstruksi menuntut penggunaan material beton dengan kualitas, kekuatan, dan durabilitas yang lebih baik. Salah satu inovasi yang dikembangkan adalah Polymer Cement Concrete, yaitu beton yang dimodifikasi menggunakan bahan polimer untuk meningkatkan sifat mekanik dan karakteristik beton. Pada polymer cement concrete terjadi kombinasi reaksi hidrasi semen, reaksi pozzolan fly ash, dan polimerisasi resin epoxy yang menghasilkan struktur beton lebih padat dan kuat. Penggunaan fly ash sebesar 5% dipilih karena mampu memperbaiki mikrostruktur beton, mengurangi porositas, serta meningkatkan kepadatan beton tanpa mengurangi workability secara signifikan. Penelitian ini bertujuan untuk menganalisis pengaruh variasi resin epoxy sebesar 0%, 2%, 4%, dan 6% terhadap kuat tekan awal dan setting time polymer cement concrete. Metode penelitian yang digunakan adalah metode eksperimental laboratorium. Campuran beton menggunakan fly ash sebesar 5% dari berat semen dan variasi resin epoxy sebesar 0%, 2%, 4%, dan 6% dari total binder. Pengujian beton segar dilakukan menggunakan slump test untuk mengetahui workability beton. Pengujian setting time dilakukan menggunakan metode penetrometer berdasarkan ASTM C403, sedangkan pengujian kuat tekan awal dilakukan menggunakan Compression Testing Machine (CTM) pada umur 3 hari, 7 hari, 14 hari, dan 28 hari. Hasil penelitian menunjukkan bahwa penambahan resin epoxy mempercepat setting time dan meningkatkan kuat tekan awal beton polymer cement concrete hingga kadar optimum tertentu. Nilai initial setting time pada variasi resin epoxy 0%, 2%, 4%, dan 6% berturut-turut sebesar 4 jam 54 menit; 3 jam 28 menit; 3 jam 32 menit; dan 4 jam 12 menit. Sedangkan nilai final setting time berturut-turut sebesar 7 jam 39 menit; 6 jam 20 menit; 5 jam 53 menit; dan 6 jam 51 menit. Nilai kuat tekan awal umur 7 hari berturut-turut sebesar 22,75 MPa; 24,52 MPa; 35,14 MPa; dan 23,01 MPa, dengan kuat tekan optimum terjadi pada variasi resin epoxy 4%. Penambahan resin epoxy berlebih sebesar 6% menyebabkan penurunan kuat tekan beton akibat beton menjadi lebih getas dan menurunkan homogenitas campuran beton.The rapid development of the construction industry demands concrete materials with better quality, strength, and durability. One of the innovations developed is Polymer Cement Concrete, which is concrete modified with polymer materials to improve its mechanical properties and performance. In polymer cement concrete, hydration reactions of cement, pozzolanic reactions of fly ash, and polymerization reactions of epoxy resin occur simultaneously, resulting in a denser and stronger concrete structure. The use of 5% fly ash was selected because it can improve the concrete microstructure, reduce porosity, and increase concrete density without significantly reducing workability. This study aims to analyze the effect of epoxy resin variations of 0%, 2%, 4%, and 6% on the early compressive strength and setting time of polymer cement concrete. This research used an experimental laboratory method. The concrete mixture utilized 5% fly ash as cement substitution and epoxy resin variations of 0%, 2%, 4%, and 6% of the total binder. Fresh concrete testing was carried out using the slump test to determine workability. The setting time test was conducted using the penetrometer method based on ASTM C403, while the early compressive strength test was performed using a Compression Testing Machine (CTM) at the ages of 3, 7, 14, and 28 days. The results showed that the addition of epoxy resin accelerated the setting time and increased the early compressive strength of polymer cement concrete up to an optimum level. The initial setting time values for epoxy resin variations of 0%, 2%, 4%, and 6% were 4 hours 54 minutes; 3 hours 28 minutes; 3 hours 32 minutes; and 4 hours 12 minutes, respectively. Meanwhile, the final setting time values were 7 hours 39 minutes; 6 hours 20 minutes; 5 hours 53 minutes; and 6 hours 51 minutes, respectively. The 7-day early compressive strength values were 22.75 MPa; 24.52 MPa; 35.14 MPa; and 23.01 MPa, respectively, with the optimum compressive strength achieved at 4% epoxy resin variation. Excessive addition of epoxy resin at 6% caused a decrease in compressive strength due to increased brittleness and reduced homogeneity of the concrete mixture.