Pengaruh Ukuran Butir Maksimum Agregat Halus terhadap Sifat Fisik dan Kekuatan Mortar Geopolimer

Abstract

Good gradation of fine aggregates in mortar serves to maximize density, strength and durability by filling cavities efficiently. This study aims to compare the physical properties and strength of geopolymer mortar with maximum grain size variations. Experimental research by making  a 50´50´50  mm mortar cube  with four variations of the maximum grain size of fine aggregate has been conducted. The constituent of geopolymer mortar consists of fine aggregates in the form of rock ash with different maximum grain sizes of 4.75 mm, 2.36mm, 1.18mm, and 0.075mm, fly ash, white soil, and mixed activators of NaOH 8M and Na₂SiO₃. The test parameters include porosity, density, absorption and compressive strength coupled with fly ash microstructure, white soil, and geopolymer mortar. The test results showed that geopolymer mortars with larger maximum grains (GT 4.75 and GT 2.36) had a more stable strength rate, although the maximum grain of a 1.18 filter (GT 1.18) produced the highest compressive strength of all variations at any age. GT 4.75 mortar has the best porosity value, but the best density and absorption are found in GT 2.36 mortar and the best compressive strength in GT 1.18 mortar. Uneven mixing of chemical compositions in geopolymer mortar allows the appearance of efflorescence which will lead to a decrease in the quality of the mortar.