Sintesis Material Seeding Calcium Silicate Hydrate untuk Meningkatkan Hidrasi Semen pada High Strength Concrete

Riyanto, Rangga Putra (2026) Sintesis Material Seeding Calcium Silicate Hydrate untuk Meningkatkan Hidrasi Semen pada High Strength Concrete. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Pemanfaatan fly ash (FA) sebesar 30% sebagai substitusi semen pada High-Strength Concrete (HSC) mampu menekan emisi karbon, namun menimbulkan tantangan berupa perlambatan hidrasi awal dan penurunan kuat tekan dini. Penelitian ini menguji penggunaan material seeding calcium-silicate-hydrate (C-S-H) sebagai akselerator fisik untuk menyediakan situs nukleasi heterogen tambahan guna mempercepat hidrasi semen tanpa menambah ion agresif. Penelitian ini bertujuan menganalisis pengaruh variasi seeding C-S-H (0%, 1%, 2%, dan 3%) terhadap waktu ikat pasta, evolusi mikrostruktur, sifat fisik/durabilitas (porositas, UPV, resistivitas, permeabilitas), serta perkembangan kuat tekan beton pada umur 3, 7, dan 28 hari. Hasil karakterisasi PSA menunjukkan material seed terdistribusi sebagai mikro-polidispers (D_10=1,75 μ"m" ; D_50=12,34 μ"m" ; D_90=32,45 μ"m" ). Pengujian vicat dan analisis mikrostruktur membuktikan bahwa dosis 2% (SEED-2) merupakan variasi paling optimal dalam merekayasa kinetika hidrasi dan pembentukan jaringan hidrasi awal, di mana initial setting time tercapai secara terukur pada 69,00 menit dengan pembentukan anyaman kristal jarum rapat (dense interlocking mesh) pada umur 1 hari, serta terhindar dari fenomena crystal impingement yang terjadi pada dosis 3% (SEED-3 dengan initial set 39,40 menit). Pada uji kinerja beton mengeras umur 28 hari, SEED-3 menghasilkan tingkat kekedapan air tertinggi dengan koefisien permeabilitas terendah (0,029×10^(-16) 〖" m" 〗^2) dan resistivitas tertinggi (39,8 "k" Ω"cm" ), nilai UPV melambat menjadi 4208,00" m/s" akibat pembiasan batas fasa mikro. Sementara itu, dosis 1% (SEED-1) menghasilkan porositas total terendah (3,26%) dan UPV tertinggi (4645,78" m/s" ). Dari sisi pengembangan kekuatan mekanis, SEED-3 memberikan peningkatan kuat tekan dini 3 hari tertinggi sebesar +56,2% (40,45 MPa) dan kuat tekan 28 hari sebesar 57,89 MPa. Kontribusi penelitian ini memberikan bukti eksperimental bahwa seeding C-S-H berbasis material lokal berhasil mengompensasi kehilangan kekuatan awal beton HSC berkadar FA 30%, dengan dosis 2% sebagai ambang batas paling optimal untuk menjaga integritas mikrostruktur dan kinetika hidrasi.
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The utilization of 30% fly ash (FA) as a partial cement replacement in High-Strength Concrete (HSC) effectively reduces carbon emissions but induces initial hydration delays and lower early compressive strength. This study investigates the application of synthesized calcium-silicate-hydrate (C-S-H) seeding material as a physical accelerator providing additional heterogeneous nucleation sites to accelerate cement hydration without introducing aggressive ions. The study aims to evaluate the effects of C-S-H seeding additions (0%, 1%, 2%, and 3%) on paste setting time, microstructural evolution, physical/durability properties (porosity, UPV, resistivity, permeability), and compressive strength development at 3, 7, and 28 days. PSA characterization confirmed that the synthesized seed existed as a micro-polydisperse material (D_10=1.75 μ"m" , D_50=12.34 μ"m" , D_90=32.45 μ"m" ). Vicat testing and microstructural analysis demonstrated that a 2% dosage (SEED-2) was the most optimal variation for engineering hydration kinetics and early structural formation, achieving a controlled initial setting time of 69.00 min and developing a dense acicular C-S-H/ettringite interlocking mesh at 1 day, while successfully avoiding the crystal impingement observed at a 3% dosage (SEED-3 with an initial set of 39.40 min). In 28-day hardened concrete tests, SEED-3 achieved the highest water tightness with the lowest permeability coefficient (0.029×10^(-16) 〖" m" 〗^2) and highest bulk resistivity (39.8 "k" Ω"cm" ), a lower UPV (4208.00" m/s" ) caused by micro-interface scattering. Meanwhile, SEED-1 yielded the lowest total porosity (3.26%) and highest UPV (4645.78" m/s" ). In terms of mechanical strength development, SEED-3 provided the highest 3-day early compressive strength boost of +56.2% (40.45 MPa) and a 28-day compressive strength of 57.89 MPa. This research provides experimental evidence that local C-S-H seeding successfully overcomes early-age strength deficits in high-volume fly ash HSC systems, establishing a 2% dosage as the optimal threshold for hydration kinetics and microstructural integrity.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	C-S-H seeding, beton berkekuatan tinggi, fly ash, hidrasi semen, waktu ikat, mikrostruktur ; C-S-H seeding, high-strength concrete, fly ash, cement hydration, setting time, microstructure
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA418.16 Materials--Testing. T Technology > TA Engineering (General). Civil engineering (General) > TA439 Lightweight concrete. High strength concrete.
Divisions:	Faculty of Vocational > 22301-Civil Infrastructure Engineering (D4)
Depositing User:	Rangga Putra Riyanto
Date Deposited:	01 Aug 2026 03:42
Last Modified:	01 Aug 2026 03:42
URI:	http://repository.its.ac.id/id/eprint/142303

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