The Effect of Granulated Blast Furnace Slag (GBFS) Composition on Geopolymer Paste Properties

Abstract

For the research study, I will perform the effect of Granulated Blast Furnace Slag (GBFS) composition on geopolymer paste properties. For my final year project, I will use raw materials of slag and fly ash that was provided in the lab. The slag and fly ash were used as the main materials in the geopolymer paste properties. Fly ash was synthesized by using sodium hydroxide (NaOH) solution and sodium silicate (Na2SiO3) solution to use as alkaline activator. There were different testing that were used in this project which are Scanning Electron Microscope (SEM) test, X-ray Fluorescence (XRF) test, Compressive test, hardness test, water absorption test and porosity test. Each of the tests was conducted to determine the chemical and mechanical properties of geopolymer paste properties. To find 28 days compressive strength, three 50mm×50mm specimens with 10, 20 and 30 percent replacement of slag were prepared and cured at 600C for 24 hours. Equivalent condition of curing was provided for the same specimens for hardness, water absorption and porositu test at 28 days for three mixtures. Sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) solution 12M with ratio 2.5 were used as alkaline activator and all parameter were kept constant to ignore other influences. The optimum rate of replacement was 30% GBFS which produce geopolymer concrete with 28 days compressive strength of 44.04 MPa, hardness of 45.57 HV, water absorption of 1.48% and porosity test of 50.70%.