Performa Beton Geopolimer Berbasis High-Calcium Fly Ash dengan Variasi Molaritas NaOH untuk Implementasi di Lingkungan Klorida

Wibowo, Yosi Noviari (2020) Performa Beton Geopolimer Berbasis High-Calcium Fly Ash dengan Variasi Molaritas NaOH untuk Implementasi di Lingkungan Klorida. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Akselerasi pembangunan infrastruktur maritim berpotensi mewujudkan pemerataan ekonomi di Indonesia. Seiring dengan pertumbuhan infrastruktur, penggunaan semen portland perlu direduksi karena menyebabkan pemanasan global. Penerapan material berwawasan lingkungan seperti halnya beton geopolimer merupakan salah satu solusi untuk untuk mengurangi resiko pemanasan global karena mengganti penggunaan semen portland sebagai material konstruksi. Beberapa peneliti mempelajari fly ash sebagai bahan penyusun beton geopolimer. Umumnya peneliti memanfaatkan low-calcium fly ash karena karakteristiknya yang bagus untuk beton geopolimer, padahal keberadaan high-calcium fly ash sangat melimpah dan menjadi limbah yang berbahaya bagi lingkungan. High-calcium fly ash sangat jarang digunakan karena karakteristiknya kurang baik apabila diterapkan sebagai bahan dasar beton geopolimer. Tingginya kadar kalsium pada fly ash menyebabkan waktu pengerasan beton geopolimer terlalu cepat, sehingga sangat sulit diimplementasikan sebagai material konstruksi skala besar. Penerapan metode pencampuran kering pernah dilakukan oleh peneliti sebelumnya untuk memperlambat waktu pengerasan beton, namun kuat tekan yang dihasilkan masih belum memenuhi persyaratan untuk material konstruksi di lingkungan klorida. Penelitian ini bertujuan untuk mengetahui komposisi optimum beton geopolimer untuk implementasi di lingkungan klorida. Metode penelitian pada tugas akhir ini terdapat 4 fase, yaitu penelitian mengenai material penyusun, mix design, pembuatan semen geopolimer, serta pembuatan beton geopolimer. Pengujian material penyusun meliputi uji XRF untuk mengetahui kandungan kimianya, serta pengujian XRD untuk mengetahui fasa amorf dan kristalin material fly ash. Fokusan tugas akhir ini terletak pada pembuatan mix design mengenai variasi molaritas NaOH (8M, 10M, 12M, dan 14M) dengan rasio Na2SiO3 : NaOH sebesar 1:1. Berbagai pengujian dilakukan untuk mengetahui performa beton geopolimer meliputi, uji kuat tekan, uji UPV, uji porositas, uji resistivitas, serta uji permeabilitas. Pengujian beton dilakukan pada umur 7, 14, 28, dan 56 hari. Selain itu juga dilakukan pengujian slump untuk mengetahui workability beton segar. Adapun perawatan benda uji yang dilakukan yaitu perawatan dengan paparan udara sekitar (ambient curing) serta perawatan di lingkungan klorida. Penambahan molaritas NaOH dengan metode pencampuran kering dapat meningkatkan performa beton geopolimer meliputi kuat tekan, kepadatan (UPV), porositas, resistivitas maupun permeabilitas. Pengujian beton dengan variasi molaritas NaOH 12M dan 14M direkomendasikan sebagai material konstrksi di lingkungan klorida karena telah memenuhi syarat SNI 2847-2019 Pasal 19.3.2 dengan kuat tekan >35MPa saat berumur 28 hari. Hasil uji workability beton geopolimer menunjukkan bahwa penambahan sukrosa 2% berpengaruh signifikan terhadap nilai slump dengan selisih nilai 85-150mm dibandingkan dengan variasi sukrosa 0%. Workability beton geopolimer telah memenuhi syarat SNI 1972-2008 dengan standar rentang 15-230 mm. Aspek analisa biaya menunjukkan bahwa implementasi beton gepoolimer lebih mahal 43%-56% dibandingkan beton konvensional. Penurunan harga produksi beton geopolimer sangat memungkinkan apabila tinjauan harga menggunakan skala komersial. ==================================================================================================================== Acceleration development of maritime infrastructure has the potential to create economic equity in Indonesia. Along with infrastructure growth, the use of portland cement needs to reduce because it causes global warming. The application of environmentally friendly materials such as geopolymer concrete is one of the solutions to reduce the risk of global warming because it replaces the use of Portland cement as a construction material. Several researchers have studied fly ash as a building material for geopolymer concrete. Generally, researchers use low-calcium fly ash due its good characteristics for geopolymer concrete, despite the fact that high-calcium fly ash is very abundant and turn to hazardous waste to the environment. High-calcium fly ash is rarely used because of its poor characteristics when applied as a main material of geopolymer concrete. The high level of calcium in fly ash causes a quick hardening time of geopolymer concrete so it is very difficult to be implemented as a large-scale construction material. Previous researchers have used the dry mixing method to slow down the hardening time of the concrete, but the compressive strength still does not meet the requirements for construction materials in chloride environments. This study aims to determine the optimum composition of geopolymer concrete for implementation in a chloride environment. The research method in this final project consists of 4 phases, including research on constituent materials, mix design, manufacture of geopolymer cement, and manufacture of geopolymer concrete. The testing of constituent materials includes the XRF test to determine its chemical content and to determine the amorphous and crystalline phases of fly ash material. The focus of this final project is about making a mix design regarding the variation of molarity of NaOH (8M, 10M, 12M, and 14M) with Na2SiO3 : NaOH ratio of 1:1. Various tests carried out to determine the performance of geopolymer concrete including compressive strength test, UPV test, porosity test, and resistivity test. Concrete testing at the ages of 7, 14, 28, and 56 days. Besides, slump testing also carried out to determine the workability of fresh concrete. The curing of the specimens is ambient curing and soaked in the chloride environment. The addition of NaOH molarity with the dry mixing method can improve the performance of geopolymer concrete including compressive strength, density (UPV), porosity, and resistivity. Concrete testing with 12M and 14M NaOH molarity variations is recommended as a construction material in a chloride environment because it has the requirements of SNI 2847-2019 Article 19.3.2 with a compressive strength > 35MPa at 28 days old. The results of the geopolymer concrete workability test showed that the addition of 2% sucrose had a significant effect on the slump value with a value difference of 85-150mm compared to the variation of 0% sucrose. The aspect of cost analysis shows that the implementation of geopolymer concrete is 43%-56% more expensive than conventional concrete. It is possible to reduce the price of geopolymer concrete production if the price review uses a commercial scale.

Item Type: Thesis (Undergraduate)
Subjects: T Technology > TH Building construction > TH1461 Concrete construction.
T Technology > TH Building construction > TH880 Sustainable buildings. Sustainable construction. Green building
Divisions: Faculty of Vocational > Civil Infrastructure Engineering
Depositing User: Yosi Noviari Wibowo
Date Deposited: 27 Aug 2020 03:38
Last Modified: 27 Aug 2020 03:38
URI: https://repository.its.ac.id/id/eprint/81222

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