Recycling of industrial waste in the manufacture of economical and quality construction blocks

Pages: 23-28
Muhammad Uzair Khanj and Kanwal Nazim (Marine Reference Collection and Resource Centre, University of Karachi, Pakistan)
Moinuddin Ahmed and Syed Shahid Shaukat (Laboratory of Dendrochronology and Plant Ecology Department of Botany and Gulshan-e-Iqbal, Karachi, Pakistan)

One of the recent trends in waste management is to recycle the industrial waste for useable products. For this purpose fiber, chemical and marble industrial wastes were used to investigate the potential of these wastes for conventional block making. The effects of industrial wastes in concrete blocks were pragmatic. The concentrations of heavy metals Co, Mn, Fe, Zn and Pb in both sludge-ashes and marble waste powder have been analyzed. The physical properties of blocks including weight, density, specific gravity, compressive strengths and percentage of water absorption were examined. As a second part of experiment leachate was obtained after soaking the blocks in distilled water for 24 hours. The physical parameters of water (leachate) such as color, pH, electrical conductivity, total dissolved solids, salinity and dissolved oxygen were determined by Sension 105 multiparameter while above mentioned heavy metals were analyzed by Atomic absorption spectrophotometer (model PG 990) to check the possible water contamination by heavy metals during the rainy season due to any seepage. Significantly higher compressive strengths 14.48 ± 0.7 N/mm2, 13.5 ± 0.4 N/mm2 and 12.53 ± 0.16 N/mm2 were recorded in M8a, F2a and M7a respectively. Fiber industry sludge-ash and marble waste powder have potential in terms of cohesive properties in the preparation of blocks. These light weight blocks were found more durable; absorb lesser amount of water and more cheaper/economic as compared to standard commercial construction blocks available in the market. It is concluded that these blocks are not only stronger than available commercial blocks but environmentally safe to be used in roads, buildings construction, boundary walls, filling material etc.