COMPARATIVE ANALYSIS OF FLY ASH AND LIME ON THE COMPRESSIVE STRENGTH OF GEOPOLYMER MORTAR

Regina Wita Pramesti (Program Studi Teknik Sipil, Fakultas Teknik, Universitas Swadaya Gunung Jati Jl. Pemuda Raya NO.32, Sunyaragi, Kec. Kesambi, Kota Cirebon, Jawabarat 45132, Indonesia)
Tira Roesdiana (Program Studi Teknik Sipil, Fakultas Teknik, Universitas Swadaya Gunung Jati Jl. Pemuda Raya NO.32, Sunyaragi, Kec. Kesambi, Kota Cirebon, Jawabarat 45132, Indonesia)

Jurnal Pensil : Pendidikan Teknik Sipil
Vol. 15 No. 2 (2026): Jurnal Pensil : Pendidikan Teknik Sipil

This study aims to analyze the effect of the variation between fly ash and lime as binders on the compressive strength of geopolymer mortar at 7, 14, 21, and 28 days of testing. Using an experimental method with mortar cured at room temperature, this study produced 60 test specimens in the form of 5 cm × 5 cm × 5 cm cubes with a ratio of 2,5:1 sand to binder and using alkali activators NaOH and Na2SiO3 with ratio of 1:2,5. The results of this study prove at the maximum compressive strength was obtained at variation of 50% FA : 50% LM at a testing age of 28 days, amounting to 21.33 MPa. Conversely, the minimum compressive strength was obtained at a variation ratio of  0% FA : 100% LM, with a value af 7.33 MPa at testing age of 28 days. The use of 50% limestone can increase stable compressive strength.