TITLE:
Characterisation and Mechanical Performance of Concrete Containing Pulverised Plastic Waste, Quarry Dust and Glass Waste as Partial Sand Replacements
AUTHORS:
Dominic Ouko Oyori, Tulatia Mungathia, Isaac Fundi
KEYWORDS:
Pulverised Plastic Waste, Quarry Dust, Glass Waste, Fine Aggregate Replacement, Compressive Strength, Water Absorption
JOURNAL NAME:
Open Journal of Civil Engineering,
Vol.16 No.3,
September
3,
2026
ABSTRACT: River sand is being drawn from Kenyan riverbeds faster than fluvial processes replace it, while plastic, glass and quarry fines accumulate in urban waste streams that municipal systems no longer absorb. This paper reports the aggregate characterisation and hardened-concrete performance of a laboratory programme in which three waste streams, namely pulverised plastic waste (PPW), quarry dust and crushed glass waste, were substituted for river sand in a nominal 1:1:2 mix by mass at a water/cement ratio of 0.50. Grading, particle density and water absorption of the aggregates were determined to BS 812, and performance was tracked through cube compression, splitting tensile, flexural and water absorption testing at 7, 14, 21 and 28 days. Twenty-nine mixes were cast across seven phases covering the control, full substitution, single-material substitution from 10% to 50%, and binary hybrids in which two wastes together formed the entire fine fraction. Fineness moduli ranged from 2.34 for quarry dust to 2.94 for glass against 2.69 for the control sand, placing all three wastes inside the sand envelope; particle density did not follow, with PPW at 1.05 g/cm3 against 2.63 g/cm3 for sand. Glass at 10% substitution reproduced the control closely (22.41 MPa against 22.96 MPa at 28 days) and full glass substitution exceeded it at 24.22 MPa. Quarry dust improved progressively to 17.44 MPa at 40% but never recovered the ground lost at full substitution. PPW depressed compressive strength in every mix in which it appeared, while lowering water absorption; the 60:40 blend of quarry dust and PPW gave the lowest 28-day absorption recorded, 4.77%. Hybrids of glass and PPW performed worst on every measure, the 60:40 blend falling to 29.61 mm slump. The findings support glass and quarry dust as viable partial sand replacements at controlled dosages, and place plastic in a permeability-reducing rather than load-bearing role.