Properties of Alternative Concrete Mixed with Non-Metallic Powder from Recycled Printed Circuit Boards
The objective of this study is to investigate the effects of using non-metallic power (NMP) as an alternative constituent on properties of concrete. The NMP was obtained during a recycling process of printed circuit board waste in a recycling plant in Thailand. Coarse-grained NMP was mixed in concrete mixture as fine aggregate (sand) replacement ranging from 0 to 50% by weight with specified water/cement ratio of 0.62. Compressive, splitting tensile, and slump tests were conducted in accordance with corresponding ASTM Standards. Test results have shown that both compressive and splitting tensile strengths gradually decreased as percentage of replacement increased. The slump of freshly mixed concrete with NMP was highest at 8 cm for 10 and 20% NMP replacements, while marked reduction was observed for concrete mixes with higher NMP replacements. On the other hand, concrete with 50% NMP replacement had lowest bulk density of 2,216 kg/m3 as expected. Considering strengths and workability attained from different mixes, this preliminary study has suggested that use of NMP in concrete is limited to no more than 20% replacement. With further development, the resulting concrete can be sustainable in a wide range of building applications, offering an alternative way for electronic waste management.
Index Terms - Concrete, Compressive strength, Non-metallic Powder, Recycled printed circuit boards