PREPARATION OF GEOPOLYMER CEMENT WITH DRY ACTIVATORS BY ONE PART SYSTEM

The geopolymer concrete(GPC) is comparitively more durable and green material with less CO2 emission and less energy consuming as compared to widely used Ordinary Portland cement (OPC). The purpose of this thesis work was an experimental study of the mechanical properties and fire resistant property of geopolymer cement prepared using a class F fly ash and two different alkali-activators (NaOH activator and Na2SiO3 activator). Basically, there are two methods for preparation of geopolymer cement – one part system and two part system. This research work deals with one part system. In one part system, the raw material and alkali activators are mixed and grind at ambient temperature in a ball mill making sure that there is no moisture present in the mix otherwise the end product may stick to the wall of Ball mill. The pellets of NaOH and powder of Na2SiO3 were mixed and grind in a dry form properly in a ball mill, after which moist free Fly-ash Powder is added to it and again grinding the mix for further which as a result forming Geopolymer cement by one part system . The compressive strength and chemical composition, are investigated. Furthermore, the effects of the water to fly-ash ratio, curing methods on the compressive strength and thermal properties of the geopolymer products are studied and analyzed in details. The tested results show that the geopolymer cement cured at appropriate temperature conditions can reach a compressive strength of more than 35MPa in 3 days and it also has an excellent heat resistance to some extent when the geopolymer cement is applied on wood sample. In addition, it is found that the water is used only to facilitate the workability and does not incorporate in the geopolymer crystal which means water is only required for mixing and handling of concrete. This paper presents an optimization of fly ash based geopolymer by one part system using dry activators to analyze on the mechanical properties of concrete produced from the optimal mixes and to conduct fire test after its application on wood samples. The weight losses were lower than that of the OPC concrete only if the cubes are kept at normal room temperature. To avoid this, we have cured the samples by oven drying at considerable temperature and time.