Prototipe Beton Geopolimer Sistem Pencampuran Kering Dengan Variasi Bahan Aditif

Rosanti, Mila (2019) Prototipe Beton Geopolimer Sistem Pencampuran Kering Dengan Variasi Bahan Aditif. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Beton geopolimer adalah beton yang dibuat tanpa semen namun digantikan dengan bahan pozzolan sumber silika (Si) dan alumina (Al) yang dapat bereaksi dengan cairan alkali aktivator yang fungsinya sama seperti semen sebagai bahan pengikat atau binder. Penelitian ini menggunakan fly ash kelas C (high-calcium fly ash) dengan kadar CaO > 10%. Fly ash kelas C ini jarang digunakan dalam campuran geopolimer pembuatan beton. Hal ini dikarenakan, setting time pada beton fly ash kelas C berlangsung cepat dan sulit diprediksi, akibat reaksi hidroliknya meningkat, seiring dengan meningkatnya kadar kalsium. Berdasarkan masalah tersebut, penelitian ini memilih metode pencampuran kering pada beton geopolimer dengan melakukan variasi bahan aditif.
Metode pencampuran kering adalah metode dimana alkali aktivator yang digunakan adalah bentuk kering (padatan) dan fly ash dihaluskan bersama untuk membuat semen geopolimer. Selanjutnya, semen geopolimer tersebut dicampur dengan air, agregat halus dan kasar untuk membuat beton geopolimer. Pada penelitian ini, membuat pasta geopolimer untuk uji setting time. Kemudian, membuat beton geopolimer untuk dilakukan uji slump, uji kuat tekan silinder 10 x 20 cm pada umur 7, 28, 56 hari, serta uji UPV pada silinder beton umur 56 hari. Pada pasta geopolimer, ada 7 macam variabel yaitu variabel kontrol, bahan aditif varibel a 2%, a 4%, a 6% dan variabel b 2%, b 4%, b 6%. Hasilnya, pasta dengan bahan aditif variabel a memiliki setting time paling lama. Sehingga variabel ini dipilih sebagai mix design pada beton geopolimer. Terdapat 4 macam variabel beton geopolimer, yaitu VC (tanpa bahan aditif), V1 (bahan aditif 6%), V2 (bahan aditif 4%) dan V3 (bahan aditif 2%). Pada mix design, perbandingan bahan pengikat : bahan pengisi adalah 30 : 70 dan untuk perbandingan fly ash : alkali aktivator adalah 65 : 35, sehingga didapatkan komposisi fly ash 468 kg/m3, NaOH 18,86 kg/m3, Na2SiO3 96,41 kg/m3 , agregat kasar 1008 kg/m3, agregat halus 672 kg/m3 dan air 136,73 kg/m3.
Hasilnya, kuat tekan rata-rata 3 silinder 10 x 20 cm beton geopolimer usia 7 hari pada VC (tanpa bahan aditif), V1 (bahan aditif a 6%), V2 (bahan aditif a 4%) dan V3 (bahan aditif a 2%) berturut-turut adalah 1,66 Mpa, 9,68 Mpa, 11,97 Mpa dan 13,24 Mpa. Penelitian ini menghasilkan beton geopolimer yang belum memenuhi target, penyebabnya antara lain, kondisi SSD agregat kurang diperhatikan, tidak dilakukan uji kekasaran agregat, proses mixing pembuatan beton tidak dilakukan dalam satu waktu, serta metode yang digunakan adalah manual, sehingga hal-hal tersebut memungkinkan terjadinya perbedaan perlakuan pada beton, dimana beton geopolimer sangat dipengaruhi oleh cuaca, suhu dan perlakuan.
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Geopolymer concrete is a concrete which made without
cement but replaced with pozzolanic material sources of silica (Si)
and alumina (Al) which can react with an alkaline liquid activator
which the function is the same as cement as a binder. This study
uses class C fly ash (high-calcium fly ash) with CaO levels > 10%.
This class C fly ash is rarely used in a mixture of geopolymer
concrete. This is because, the setting time of class C fly ash
concrete is fast and difficult to predict, due to the increase of
hydraulic reaction, along with increasing calcium levels. Based on
these problems, this study chose the dry mixing method in
geopolymer concrete by varying additives.
Dry mixing method is a method where the alkali activator used
is a dry form (solid) and fly ash is mashed together to make
geopolymer cement. Furthermore, the geopolymer cement is mixed
with water and aggregate to make geopolymer concrete. This
study, was made geopolymer paste to test setting time. Then, made
geopolymer concrete for slump test, compressive strength test of
cylinder 10 x 20 cm on age 7, 28, 56 days, and UPV test on concrete
aged 56 days. In geopolymer paste, there are 7 types of variables,
namely variable control, a2%, a4%, a6% and b2%, b4%, b6%. As a result, pasta with variable a has the longest setting time. So that
this variable was chosen as a mix design on geopolymer concrete.
There are4 types of geopolymer concrete variables, namely VC
(without additives), V1 (6% additives), V2 (4% additives) and V3
(2% additives). In mix design, the ratio of binder: filler material is
30: 70 and for comparison of fly ash: alkali activator is 65: 35, so
that the composition of fly ash is 468 kg/m3, NaOH is 18.86 kg/m3,
Na2SiO3 is 96.41 kg/m3, coarse aggregates 1008 kg/m3, fine
aggregates 672 kg/m3and water 136,73 kg/m3.
The result is, the average compressive strength of geopolymer
concrete cylinders aged 7 days on VC (without additives) is 1,66
Mpa, and then V1 (6% additives) is 9,68 Mpa, on V2 (4% additives)
is 11,97 Mpa and V3 (2% additives) is 13,24 Mpa.
This study produced geopolymer concrete that did not achieve
the target, it can cause by many factors, there are; the condition of
the SSD aggregate was not considered, no aggregate roughness
testing, the concrete mixing process wasn’t done at one time, and
the method that used was manual, so that there are differences
treatment in concrete, where geopolymer concrete is strongly
influenced by weather, temperature and treatment

Item Type:	Thesis (Undergraduate)
Additional Information:	RSIS 620.136 Ros p-1 2019
Uncontrolled Keywords:	geopolimer, bahan aditif, metode pencampuran kering, setting time, kuat tekan, geopolymer, additives material, dry mixing method, compressive strength
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA441 Aggregates T Technology > TA Engineering (General). Civil engineering (General) > TA455.S6 Soil (Materials of engineering and construction) T Technology > TA Engineering (General). Civil engineering (General) > TA681 Concrete construction
Divisions:	Faculty of Vocational > Civil Infrastructure Engineering (D4)
Depositing User:	Mila Rosanti
Date Deposited:	04 Oct 2021 08:01
Last Modified:	04 Oct 2021 08:01
URI:	http://repository.its.ac.id/id/eprint/61323

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