PENGARUH KADAR SOLID LARUTAN AKTIVATOR TERHADAP KUAT TEKAN MORTAR GEOPOLIMER BERBAHAN DASAR ABU TERBANG (FLY ASH) DAN NaOH 12 M PADA KONDISI SS/SH 1,5 DAN 3,5 PADA TEMPERATUR NORMAL

Abstrak Kebutuhan akan beton sebagai material dalam dunia konstruksi terus meningkat begitupun dengan kebutuhan akan Portland semen. Portland semen menyumbang emisi gas CO2 ke udara sehingga berdampak buruk bagi lingkungan. Pembuatan beton geopolimer berbahan dasar fly ash dapat membantu mengurangi penggunaan Portland semen.Penelitian ini bertujuan untuk menemukan pengaruh kadar solid larutan aktivator (w/s) terhadap kuat tekan mortar geopolimer serta menemukan nilai w/s yang optimum untuk mendapatkan kuat tekan yang terbesar dalam kondisi rasio SS/SH sebesar 1.5 dan 3.5. Adapun nilai w/s yang digunakan adalah sebesar 0,2; 0,25; 0,30; 0,35; 0,40; 0,45.Hasil penelitian menunjukkan bahwa kadar solid larutan aktivator (w/s) dapat mempengaruhi kuat tekan mortar geopolimer. Hasil kuat tekan mortar kondisi SS/SH =1.5 terus meningkat dari nilai w/s=0,2 hingga puncaknya w/s=0,3 mampu mencapai nilai 66,67 MPa, sedangkan mortar kondisi SS/SH = 3.5 menunjukan model kenaikan yang sama hingga puncaknya w/s=0,3 mampu mencapai nilai kuat tekan 63,06 MPa . Setelah nilai w/s telah lebih dari 0,3, maka kuat tekannya menurun. Maka diperoleh bahwa kadar solid larutan aktivator (w/s) yang optimum pada kondisi SS/SH=1.5 dan 3.5 adalah 0,3. Kata kunci : Mortar Geopolimer, Fly Ash, Rasio W/S, Molaritas, SS/SH, Kuat Tekan, Suhu Ruangan Abstract The global use of concrete as construction material increasing Portland cement consumption. Portland cement produces and releases CO2 emissions into the atmosphere that gives negative impacts to environment. Fly ash-based geopolymer concrete are also considerable for reduce the use of ordinary Portland cement.This research aims to get the influence of alkaline avtivator’s solution density against compressive strength of fly ash-based geopolymer mortar and find an optimum water solid ratio (w/s ratio) to obtained maximum compressive strength in certain condition of sodium silicate to sodium hidroxide comparison between 1.5 and 3.5. Water solid ratio that used in this research was 0,2; 0,25; 0,30; 0,35; 0,40; 0,45.The results showed that alkaline activator’s solution density (w/s ratio) was able to give influence against compressive strength of fly ash-based geopolymer mortar. The compressive strength of fly ash-based geopolymer mortar in SS/SH=1.5 condition has increased continuously from w/s ratio =0.2 till reached its maximum compressive strength in w/s ratio =0.3 condition and obtained 66.67 MPa, while Fly ash-based geopolymer mortar in SS/SH=3.5 condition showed similar increasing trend and reached its maximum compressive strength at 63.06 MPa. After water solid ratio reached 0.3 mortar can not reach higher compressive strengh anymore even if it has higher water solid ratio. This research found that 0.3 was the optimum water solid ratio (w/s ratio) at SS/SH=1.5 and 3.5 condition. Keywords : Geopolymer Mortar, Fly Ash, Water Solid Ratio (w/s ratio), Molarity, Sodium Silicate to Sodium Hidroxide Ratio (SS/SH ratio), Compressive Strength, Room Temperature