Studi Eksperimental Tegangan Regangan Kolom Pendek Beton Geopolimer Penampang Lingkaran

Rohmadhon, Muh. Ibnu (2024) Studi Eksperimental Tegangan Regangan Kolom Pendek Beton Geopolimer Penampang Lingkaran. Diploma thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Pemanfaatan fly ash sebagai pengikat pada beton geopolimer merupakan alternatif ramah lingkungan dalam konstruksi karena dapat mengurangi dampak emisi CO2. Fly ash sebagai limbah hasil pembakaran batu bara, memerlukan aktivator Natrium Hidroksida (NaOH) dan Natrium Silikat (Na2SiO3). Metode pencampuran kering digunakan dengan menambahkan sukrosa sebagai superplasticizer. Penelitian ini bertujuan untuk menguji pengaruh kekangan terhadap perilaku beton geopolimer. Sampel uji terdiri 12 silinder dengan ukuran 150 cm x 300 cm dibuat dengan beton geopolimer dibagi atas 4 silinder dengan jarak sengkang spiral 75mm, 4 silinder dengan jarak sengkang 50mm dan 4 silinder beton geopolimer tanpa kekangan. Variabel yang dipertimbangkan dalam penelitian ini adalah jarak sengkang spiral dan tulangan longitudinal dengan menggunakan tulangan diameter Ø6. Pengujian menggunakan load cell untuk mengukur tegangan dan LVDT untuk mengukur regangan pada spesimen. Pengujian mengacu pada SNI 1974-2011. Pengaruh jarak antar sengkang dan strain gauge mempengaruhi penambahan kekuatan tekan dan regangan pada tulangan inti kolom. Penggunaan rumus P0 kolom diterapkan untuk mendapatkan nilai kuat tekan aksial maksimum yang divalidasi dengan hasil eksperimental kolom pendek beton geopolimer. Model analitik dari peneliti Mander, Attard, dan Ganesan digunakan sebagai perbandingan dengan hasil eksperimen. Hasil pengujian menunjukkan bahwa kekangan secara signifikan meningkatkan kekuatan tekan dan regangan kolom pendek beton geopolimer. Kolom dengan jarak sengkang spiral 75 mm dan 50 mm mengalami peningkatan kekuatan tekan berturut-turut sebesar 16% dan 25%, serta peningkatan regangan sebesar 25% dan 90%, dibandingkan dengan kolom tanpa kekangan yang didapatkan nilai kuat tekan 38,13 MPa dan regangan sebesar 0.002 mm. Kekangan juga memperbaiki kinerja kolom pasca-kerusakan ditandai dengan pengurangan retakan pada selimut kolom. Hasil pengukuran tegangan regangan tulangan dari strain gauge bahwa tulangan lentur dan tulangan spiral pada benda uji kolom pendek beton geopolimer pada saat tegangan mencapai 32 Mpa tulangan baja mulai leleh. Regangan maksimum yang terjadi pada tulangan lentur sebesar 1,61x10-3 mm/mm, sedangkan untuk tulangan spiral sebesar 1,59 x 10-3 mm/mm. Selain itu, kekangan lateral mengurangi efek buckling dan meningkatkan ketahanan kolom terhadap beban aksial. Rumus P0 kolom menurut SNI 2847-2019 menunjukkan relevansi dengan hasil eksperimen, dimana perkiraan kekuatan desain ultimit kolom pendek beton geopolimer berkisar antara 80% hingga 82% dari kekuatan puncak. Perumusan konstitutif dari model analitik terpilih yaitu pemodelan Attard dan dimodifikasi untuk mendapatkan kurva tegangan regangan yang menyerupai hasil eksperimental.
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The utilization of fly ash as a binder in geopolymer concrete is an environmentally friendly alternative in construction because it can reduce the impact of CO2 emissions. Fly ash, as a waste from coal combustion, requires activators of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). Dry mixing method is used by adding sucrose as superplasticizer. This study aims to examine the effect of restraint on the behavior of geopolymer concrete. The test samples consisted of 12 cylinders of size 150 cm x 300 cm made with geopolymer concrete divided into 4 cylinders with 75mm spiral stirrup spacing, 4 cylinders with 50mm stirrup spacing and 4 cylinders of geopolymer concrete without restraint. The variables considered in this study are spiral stirrup spacing and longitudinal reinforcement using Ø6 diameter reinforcement. The test used load cell to measure the stress and LVDT to measure the strain on the specimen. The test refers to SNI 1974-2011. The influence of the distance between stirrups and strain gauge affects the additional compressive strength and strain on the column core reinforcement. The use of the column P0 formula was applied to obtain the maximum axial compressive strength value validated by experimental results of geopolymer concrete short columns. Analytical models from researchers Mander, Attard, and Ganesan were used for comparison with experimental results. The test results showed that the restraints significantly improved the compressive strength and strain of the geopolymer concrete short columns. Columns with spiral stirrup spacing of 75 mm and 50 mm experienced an increase in compressive strength of 16% and 25%, respectively, and an increase in strain of 25% and 90%, respectively, compared to columns without restraints which obtained a compressive strength value of 38.13 MPa and strain of 0.002 mm. The restraints also improved the post-damage performance of the columns as indicated by the reduction of cracks in the column covers. The results of reinforcement stress-strain measurements from the strain gauge showed that the flexural reinforcement and spiral reinforcement in the geopolymer concrete short column test specimens when the stress reached 32 MPa the steel reinforcement began to melt. The maximum strain that occurred for flexural reinforcement was 1.61x10-3 mm/mm, while for spiral reinforcement it was 1.59x10-3 mm/mm. In addition, lateral restraint reduces the buckling effect and increases the column's resistance to axial loads. The column P0 formula according to SNI 2847-2019 shows relevance to the experimental results, where the estimated ultimate design strength of geopolymer concrete short columns ranges from 80% to 82% of the peak strength. The constitutive formulation of the analytical model was selected as Attard modeling and modified to obtain stress-strain curves that resemble the experimental results.

Item Type:	Thesis (Diploma)
Uncontrolled Keywords:	beton geopolimer, kekangan, kekuatan tekan, tegangan regangan, kolom pendek, geopolymer concrete, restraint, compressive strength, stress strain, short column
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA433 Strength of materials. T Technology > TA Engineering (General). Civil engineering (General) > TA440 Concrete--Cracking. T Technology > TA Engineering (General). Civil engineering (General) > TA444 Reinforced concrete T Technology > TA Engineering (General). Civil engineering (General) > TA660.C6 Columns
Divisions:	Faculty of Vocational > Civil Infrastructure Engineering (D4)
Depositing User:	Muh. Ibnu Rohmadhon
Date Deposited:	22 Aug 2024 06:26
Last Modified:	22 Aug 2024 06:26
URI:	http://repository.its.ac.id/id/eprint/112470

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