Performance of Artificial Coarse Aggregates from a Mixture of Hampangen Clay and Palm Shell Charcoal by Geopolymerization Method

Artificial coarse aggregates are created using geopolymerization methods to reduce high energy consumption. Raw materials rich in silica and alumina are mixed with an activator solution. Different sources of raw materials, although the materials are the same, cause the mineral content and chemical composition also to be different. There needs to be studies being done to obtain an artificial coarse aggregate mixture, including the effects of variations in the ratio of molar SiO₂ to Na₂O, the molar ratio of H₂O to Na₂O, and variations in the molar ratio of Na₂O to Al₂O_3, as well as the effect of adding palm shell charcoal to the raw materials of Hampangen clay. Then the manufacture of coarse aggregate granules was carried out, and continued with the manufacture of a concrete mixture with a cylinder size of 100 mm and a height of 200 mm. The study showed that the addition of SiO₂ concentrations in the activator solution has a certain value limit so that the paste can harden. Molar ratio H₂O to Na₂O and the molar ratio of Na₂O to Al₂O, have a noticeable effect on the compressive strength of the resulting paste. And there is a very strong relationship between the addition of palm shell charcoal to the compressive strength of the paste. The more charcoal the palm shell, the higher the compressive strength value of the paste. The properties of artificial coarse aggregates are light and are used as a material for the formation of lightweight concrete mixtures. The performance of artificial coarse aggregates is categorized as structural lightweight concrete.