Palm Oil Fuel Ash and Mussel Shell Powder as Supplementary Cementitious Materials in Non-Load Concrete Brick

The pozzolanic properties of the industrial by-product palm oil fuel ash (POFA) has given this material a unique characteristic that can be used as a cement substitute. Meanwhile, the abundance of waste seashells which contain an enormous amount of calcium oxide (CaO) available around the world has led this material to be another potential waste material as substitutes for conventional materials in concrete. The percentage amount of POFA used as a replacement was constant at 20% from the amount of cement. On the other hand, mussel shell powder (MSP) was replaced by 2%, 4%, 6% and 8% with the decrement of 2% of OPC used for each of the design. The physical and chemical properties of the materials and the mechanical properties of concrete brick were identified for 7, 14 dan 28 days. The inclusion of POFA and MSP in the concrete brick mix in this study reduced the compressive strength of the concrete in the early days and enhanced at the late stages. Apart from that, the compressive strength of the concrete brick mixtures decreased along with the increasing percentage of MSP as the increment content of CaO from MSP reduced the hydration process. The optimum percentage of MSP replacement in this study is 4% with 20% replacement of POFA and 76% OPC. The application of these materials as supplementary cementitious materials in the construction industry, particularly in producing non-load concrete brick will simultaneously encourage reducing potential pollutions and promote sustainability.