The effect of calcium oxide addition from feather clam shells on porosity and water adsorption geopolymer composite bricks

The purpose of this study was to study the effect of adding CaO (calcium oxide) from clam shell ash on physical properties such as density, porosity and water absorption on geopolymer composite bricks. Geopolymer composite bricks are made by mixing sand, geopolymers synthesized from fly ash with NaOH and Na2SiO3 and calcium oxide calcined from feather clam shell which is printed in cylinder form. The bricks are then cured for 28 days and physical tests are carried out in the form of density, water absorption and porosity tests. The results showed that the most optimal addition of CaO is 7.5% for the physical properties of geopolymer composite bricks with a density value of 1.80 gr/cm3, a porosity value of 10.30% and a water absorption capacity of 4.68%. The value has filled the quality standard 1st for bricks set by Indonesian National Standard (SNI).