Assessing the impact of waste glass and metakaolin on the durability and mechanical strength properties of concrete

ABSTRACT

In the face of environmental challenges stemming from the accumulation of waste glass and cement production, significant contributors to CO₂ emissions, this study explores sustainable construction alternatives by incorporating waste glass (WG) and metakaolin (MK) as partial cement substitutes. Experimental Various concrete mixes containing different percentages of WG and MK (10%, 20%, 30% for WG, and 15% for MK) were evaluated against a standard reference mix. Analyses focused on workability, compressive strength, water absorption, electrical resistivity, ultrasonic pulse velocity (UPV), and chloride ion penetration. The results showed that mixes with 20WG and 30WG enhanced fluidity by 16.67%. In the hardened state, mixes with 10WG and 15MK recorded compressive strength increases of 31.5% and 25.97% at 91 days, respectively. Further tests on electrical resistivity, UPV, and chloride ion penetration indicated that WG and MK contribute to a denser and less porous concrete microstructure, improving durability against chloride ingress. Additionally, water absorption did not increase proportionally with strength, suggesting that other factors beyond porosity influence strength. These findings support the use of glass waste and metakaolin in concrete production to promote more sustainable building practices and extend the lifespan of concrete structures.

Keywords:
Sustainable Construction; Waste glass; Metakaolin; Compressive Strength; Durability of Concrete