Pengaruh Variasi Molaritas Natrium Hidroksida Terhadap Performa Tensile Strength Beton Geopolimer Berbasis High-Calcium Fly Ash

Ageng, Jaka Perwira (2021) Pengaruh Variasi Molaritas Natrium Hidroksida Terhadap Performa Tensile Strength Beton Geopolimer Berbasis High-Calcium Fly Ash. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

Text 10111710013072-Undergraduate_Thesis.pdf - Accepted Version Restricted to Repository staff only until 1 October 2023. Download (4MB) | Request a copy

Abstract

Seiring dengan meningkatnya pertumbuhan infrastruktur, maka produksi semen sebagai material utama akan semakin meningkat pula. Namun, produksi semen sendiri berdampak negatif bagi lingkungan. Penggunaan material ramah lingkungan seperti geopolimer menjadi solusi untuk mengatasi hal ini. Beberapa peneliti mempelajari fly ash sebagai bahan penyusun beton geopolimer. Adapun karakteristik material fly ash di Indonesia adalah high-calcium fly ash. Fly ash ini 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. Beberapa penelitian dilakukan untuk memperpanjang waktu pengerasan beton geopolimer berbasis high-calcium fly ash diantaranya adalah penerapan metode pencampuran kering dan penambahan sukrosa. Keduanya terbukti mampu meningkatkan workability dari beton geopolimer. Kelemahan dari beton adalah kuat tariknya yang rendah. Namun sayangnya, penelitian terkait parameter ini sangat jarang dilakukan. Peningkatan molaritas alkali aktivator berpotensi meningkatkan performa tensile strength dari beton. Namun demikian, penggunaan molaritas yang terlalu tinggi juga menyebabkan turunnya performa beton geopolimer.
Metode penelitian pada tugas akhir ini terdapat 5 fase, yang meliputi studi literatur, pengujian material penyusun, pembuatan 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 senyawa material fly ash. Fokus tugas akhir ini adalah untuk mengetahui performa tensile strength beton geopolimer dengan melakukan percobaan variasi molaritas NaOH (12M, 14M, 16M, dan 18M) dan rasio Na2SiO3 : NaOH sebesar 0,67.
Berbagai pengujian dilakukan untuk mengetahui performa beton geopolimer meliputi, uji kuat tekan, uji UPV, dan uji kuat tarik. Pengujian beton dilakukan pada umur 7, 14, dan 28 hari. Pada penelitian ini, terjadi peningkatan kuat tekan dan kuat tarik beton seiring peningkatan molaritas dari 12 M ke 14 M. Kuat tekan dan kuat tarik tertinggi diperoleh pada variasi 14 M berturut-turut sebesar 67,57 MPa dan 5,03 MPa. Penggunaan NaOH dengan molaritas yang lebih tinggi (16 M dan 18 M) menurunkan performa dari beton. Adapun rasio antara kuat tarik dan kuat tekan tertinggi diperoleh sebesar 5%. Nilai ini relatif lebih baik dibanding beton normal pada kuat tekan yang sama. Dari segi workability sendiri, nilai slump beton mengalami penurunan seiring dengan meningkatnya molaritas NaOH yang digunakan. Namun, nilai slump pada penelitian ini memenuhi standar SNI 1972-2008 yang mensyaratkan sebesar 15-230 mm. Dengan demikian, beton geopolimer berbasis high-calcium fly ash berpotensi untuk digunakan sebagai material konstruksi skala besar.
================================================================================================
Along with increasing infrastructure growth, the production of cement as the main material will also increase. However, cement production itself has a negative impact on the environment. The use of environmentally friendly materials such as geopolymers is solution to overcome this. Several researchers studied fly ash as constituent of geopolymer concrete. The characteristics of fly ash in Indonesia are high-calcium fly ash. High-calcium fly ash is rarely used because of its poor characteristics when applied as geopolymer concrete. The high calcium content in fly ash causes the geopolymer concrete setting time too fast, making it very difficult to implement. Several studies were carried out to extend the hardening time, including the application of the dry mixing method and addition of sucrose. Both are proven to be able to increase the workability of geopolymer concrete. The disadvantage of concrete is its low tensile strength. But unfortunately, research related to this parameter is very rarely done. Increasing the molarity of alkaline activator potentially increase the tensile strength performance of concrete. However, the use of too high molarity also causes decrease in the performance it.
The research method in this project has 5 phases, which include literature studies, materials testing, mix designs, making geopolymer cement, and making geopolymer concrete. The testing of materials includes the XRF test to determine the chemical content, as well as the XRD test to determine the phases of fly ash. The focus of this research is to determine the tensile strength performance of geopolymer concrete by experimenting various NaOH molarity (12M, 14M, 16M, and 18M) and the ratio of Na2SiO3: NaOH of 0.67.
Various tests were carried out to determine the performance of geopolymer concrete including compressive strength test, UPV test, and tensile strength test. Concrete testing was carried out at the age of 7, 14, and 28 days. In this study, there was an increase in the compressive strength and tensile strength of concrete as the molarity increased from 12 M to 14 M. The highest compressive strength and tensile strength were obtained at the variation of 14 M at 67.57 MPa and 5.03 MPa, respectively. The use of NaOH with higher molarity (16 M and 18 M) reduces the performance of the concrete. The ratio between the highest tensile strength and compressive strength was obtained at 5%. This value is relatively better than normal concrete at the same compressive strength. In terms of workability itself, the slump value of concrete decreased along with the increase in the molarity of the NaOH used. However, the slump value in this study meets the 1972-2008 SNI standard which requires 15-230 mm. Thus, geopolymer concrete based on high-calcium fly ash has the potential to be used as large-scale construction material.

Item Type:	Thesis (Undergraduate)
Uncontrolled Keywords:	Beton Geopolimer, High-Calcium Fly Ash, Metode Pencampuran Kering, Tensile Strength
Subjects:	H Social Sciences > HD Industries. Land use. Labor > HD9622 Cement. Concrete. Cement and concrete additives T Technology > TA Engineering (General). Civil engineering (General)
Divisions:	Faculty of Vocational > Civil Infrastructure Engineering (D4)
Depositing User:	JAKA PERWIRA AGENG
Date Deposited:	29 Aug 2021 17:43
Last Modified:	29 Aug 2021 17:43
URI:	http://repository.its.ac.id/id/eprint/90413

Actions (login required)

View Item