Civil Engineering and Architecture Vol. 13(3A), pp. 2518 - 2530
DOI: 10.13189/cea.2025.131324
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The Utilization of Bungkulan Pumice Soil as Geopolymer Binder

I Nyoman Sutarja ¹, Ni Kadek Astariani ^2,*, Ngurah Sedana Putra ^1
1 Magister of Civil Engineering, Udayana University, Indonesia
² Department of Civil Engineering, Universitas Ngurah Rai, Indonesia

ABSTRACT

The innovation of using pumice as a basic material for traditional Balinese ornaments is increasingly widespread, especially in public facilities and holy places. In practice, natural pumice ground is mixed with portland cement as a binder before being molded and carved. To meet sustainable green building standards, the use of pozzolan cement needs to be reduced and replaced with more environmentally friendly materials. Bungkulan pumice soil (BPS) is the precursor material (P) used in this research, plus the alkali activator (A), sodium hydroxide (NaOH), and sodium silicate (Na₂SiO₃). Samples were made with 3 variations of PC (control) with a mixture of Portland cement and pumice soil (1:3). BPS-1 and BPS-2 samples were prepared with precursor and activator ratios (75%:25%) and (80%:20%), respectively. The activator ratio (Na₂SiO₃: NaOH) is 2:1 and the molarity concentration is 12M. For every variant, three samples were created and evaluated at 7, 14, 21, and 28 days of age. The sample with the BPS-2 code had the highest compressive strength and tensile strength results. SEM-EDX microstructural examinations were also performed on the samples with the results that the samples mixed with portland cement (PC) had more pore space compared to the geopolymer species (BPS-1 and BPS-2) because they did not use an activator to increase the density between the pores. Geopolymer can be an environmentally friendly alternative material for Balinese ornaments considering their mechanical and microstructural characteristics.

KEYWORDS
Pumice Soil, Compressive Strength, Microstructure, Geopolymer Binder, Split Tensile Strength

Cite This Paper in IEEE or APA Citation Styles
(a). IEEE Format:
[1] I Nyoman Sutarja , Ni Kadek Astariani , Ngurah Sedana Putra , "The Utilization of Bungkulan Pumice Soil as Geopolymer Binder," Civil Engineering and Architecture, Vol. 13, No. 3A, pp. 2518 - 2530, 2025. DOI: 10.13189/cea.2025.131324.

(b). APA Format:
I Nyoman Sutarja , Ni Kadek Astariani , Ngurah Sedana Putra (2025). The Utilization of Bungkulan Pumice Soil as Geopolymer Binder. Civil Engineering and Architecture, 13(3A), 2518 - 2530. DOI: 10.13189/cea.2025.131324.