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Journal : Sinergi

Engineering properties of seawater-mixed mortar with batching plant residual waste as aggregate replacement Astuti, Pinta; Pramana, Alfido Adhi; Rafdinal, Rahmita Sari; Purnama, Adhitya Yoga; Arifan, Rusdi Sahla; Monika, Fanny; Habirun, Asiya Nurhasanah
SINERGI Vol 28, No 2 (2024)
Publisher : Universitas Mercu Buana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22441/sinergi.2024.2.017

Abstract

This research showcased the use of leftover trash as a substitute for aggregate in mortar combined with saltwater. The raw waste materials underwent analysis using X-ray fluorescence (XRF) in order to determine the component materials and crystalline phases present. The choice of Portland composite cement (PCC) was made because of its durability in a hostile environment. Seawater is used to combat the water crisis and prevent corrosion, thanks to its exceptional resistance to corrosion. The attributes of mortar were assessed in terms of its fresh characteristics (slump and flow table) as well as its mechanical properties (compressive strength, split tensile strength, flexural strength, density, and shrinkage). The findings indicate that the dried mortar waste is suitable as a patch repair material for a substrate with a strength of 20 MPa, but only when utilized in a maximum quantity of 20% and with a water-to-cement ratio of 0.3. The repaired concrete with a strength of 25 MPa did not need any waste containment and had a maximum water-to-cement ratio (W/C) of 0.3, whether combined with saltwater or tap water. The possible role of the mortar containing the dried waste was to be the species for brick and other non-structural. Additionally, the use of an alternative cementitious substance is suggested to enhance the effectiveness of the patch repair material, particularly when paired with cathodic corrosion protection in damaged concrete
Investigation of mechanical properties and microstructural characteristics of rice husk ash-based geopolymer mortar as patch repair Astuti, Pinta; Isnaini, Muhammad Sakti; Sasmita, Devi; Purnama, Adhitya Yoga; Habirun, Asiya Nurhasanah; Zulkarnain, Anisa; Nouvaldi, Angga Jordi; Monika, Fanny
SINERGI Vol 29, No 2 (2025)
Publisher : Universitas Mercu Buana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22441/sinergi.2025.2.009

Abstract

The rapid expansion of the construction sector has escalated cement use, significantly impacting the environment due to CO2 emissions. Geopolymers are eco-friendly construction materials designed to reduce cement use and have the potential to be a patching material to rehabilitate concrete structures due to corrosion damage. Among these, pozzolanic materials like rice husk ash, rich in aluminosilicate, are abundant and suitable for geopolymer binders. This study explored the use of rice husk ash and alkali activators (NaOH/Na2SiO3), with different activator percentages (40%, 45%, and 50%), to evaluate their mechanical properties and potential applications as patch repair materials. This research involved formulating an optimal mix design through trial and error in a laboratory setting, followed by curing at 70 °C and testing at room temperature. XRF and SEM-EXD analyses were performed to determine the chemical composition and microstructure of the specimens. The activators, NaOH and Na2SiO3, were employed in a 1:3.5 ratio, with 14M molarity and 2% superplasticizer, to enhance workability. The test yielded the geopolymer mortar’s highest compressive strength of 8.14 MPa at a 40% activator variation. In comparison, the highest split tensile and flexural strengths were 2.50 MPa and 1.00 MPa, respectively, both at a 50% variation. These findings demonstrated the suitability of the mortar for patch repair on concrete substrates with compressive strengths below 8 MPa. The mechanical properties of the rice husk ash geopolymer mortar were influenced by the silica, calcium, and alkali activator content, affecting the mortar’s strength and density.