PARTIAL REPLACEMENT OF COARSE AGGREGATES WITH PLASTIC POLYURETHANE (PPU) COATED VOLCANIC TUFF AS A LIGHTWEIGHT STRUCTURAL CONCRETE
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Date
2025-12-11
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Uganda Christian University
Abstract
In this research, the applicability of plastic-polyurethane (PPU) coated volcanic tuff mixed with shredded PET plastics, as a partial substitute of traditional coarse aggregates in C25 structural concrete, was studied. It is about the necessity of low-density structural materials of Uganda and the shortage of volcanic tuff, which is naturally porous and therefore mechanically weak. It was tested using aggregate characterization and concrete testing with 0, 10, 20, and 30 percent replacement levels by the BS EN and ASTM standards.
PU coating made volcanic tuff much less absorptive and enhanced the integrity of the aggregate, yet the composite was still more porous than crushed rock. The higher the replacement the lower was the workability; hardened density declined by 3-12 percent, which is evidence of effective dead-load reduction. The rate of water absorption rose to an average extent, which is a characteristic of the microstructure of the composite. The results of compressive strength revealed that 10 percent replacement attained comparable strength at 28 days as the control mix and C25 requirements, but increased replacement percentages resulted in a gradual decline in strength.
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UNDERGRADUATE RESEARCH