Study of Radon-222 emanations from fabricated composite brick based on treated kenaf fiber

Radon is a natural radioactive gas that is derived from the decomposition of Uranium-238 in the soils, rocks and water. It is a harmful gas that can harm the surrounding environment and human health which is the second factor that causes the lung cancer after the cigarette smoking. The main natural sources of indoor of radon that are containing the traces of Uranium-238 are soil, building materials (sand, stone and cement), natural energy sources (gas) and coal. This study was conducted to see whether the fabricated of composite brick based on treated kenaf fiber with different amount of raw materials can reduce the Rn-222 emanation to the surrounding. In this study, Rn-222 concentration had been measured for four different fabricated brick in Perspex box by using Radon Sentinel Model 1030. Three composite brick were added 10 g of treated kenaf fiber for each brick. The Rn-222 concentration for four brick was taken for three days for each brick. The factors that influence the Rn-222 concentration such as humidity, temperature and pressure also determined. The addition of kenaf fiber to replace the amount of raw materials also influenced the Rn-222 concentration. Composite brick 2 shows the highest average of Rn-222 concentration which is 4.1 pCi/L. The water absorption behaviour of kenaf fiber increases the humidity in the composite brick. High humidity affects the concentration of Rn-222 brick composites. Concrete brick shows the lowest average of Rn-222 concentration which is 1.0 pCi/L. The mechanical strength of four fabricated brick had been determined by compression test using the Universal Testing Machine (UTM). The composite brick 1 has the highest mechanical strength because the value of force to break is highest at 50526 N. Treated kenaf fiber with sodium hydroxide solution for alkaline treatment had improved the mechanical properties of the composite brick. The concrete brick has the lowest mechanical strength which is 50494 N for value force to break.