RECYCLING OF LANDFILL WASTE IN THE MANUFACTURE OF BUILDING BRICKS [ ]


A landfill solid waste obtained from a location in Delta region –Egypt was used in the manufacturing of fired clay bricks by blending with clay, as eco friendly waste recycling process. This affords utilizing a priceless waste while simultaneously minimizing pollution. Raw materials were characterized for their chemical and mineralogical composition using XRF and XRD respectively; the particle size distribution of both clay and waste was assessed by sieving. Mixtures were prepared by blending up to 35% waste with clay. Brick specimens for each mixture were molded, dried then fired. Tests performed on the wet mixes showed that waste addition caused a slight decrease in plasticity up to about 20% addition. Also the dry compressive strength was almost unaffected by the addition of waste up to 25% addition. On firing for 3 hours at temperatures ranging from 700 to 850 °C the percent boiling water absorption as well as apparent porosity regularly increased on waste addition associated with a decrease in bulk density and hence the weight of produced bricks. One remarkable feature was the elevated compressive strength obtained on adding up to 20% waste and firing at 800 °C (25 – 30 MPa) that exceeded by far the standard requirements for normal duty clay bricks according to ASTM C 62/2013 (8.6 MPa).This was interpreted in the light of formation of diopside and anhydrite that confer high mechanical properties to the fired body. Firing at higher temperatures besides being less economical caused excessive black core formation resulting in bursting of the bricks for waste addition exceeding 10%. It was concluded that the replacement of 10 – 15 wt. % of clay by the dump solid waste site and firing at 700 °C, improved brick quality as well as contributing to minimize pollution.