EFFECT OF GLASS POWDER ON DURABILITY PERFORMANCE OF HARDENED CONCRETE IN AGGRESSIVE ENVIRONMENT

Abstract

Concrete structures exposed to aggressive environment such as sewer water, sea fronts, drains among others are susceptible to abrasion, chemical seepage among other factors that lead to its deterioration. To mitigate deterioration of concrete, various methods have been proposed such as use of supplementary cementitious materials, regular replacement of worn-out sections among other considerations. This research recommends use of glass powder as an additive to concrete mixture to mitigate risks associated with concrete deterioration due to exposure to aggressive environment with the aim of determine its effect on durability parameters. This study was guided by objectives considering concrete water absorptivity, resistance to sulphate attack and its chloride permeability. Crushed waste glass powder was added to the concrete mix at 10%, 20% and 30% by weight of cement. Fresh concrete was subjected to slump test while hardened concrete was subjected to compressive strength, water absorption, sulphate attack and electrical resistivity tests. The data obtained were computed and comparison made with the control samples at maturity and presented in forms of tables and graphs. Best results relative to the control samples were obtained at 30% addition of crushed waste glass powder into the concrete mix, with a notable increase in compressive strength from 32.8 N/mm2 to 42.8 N/mm2 representing an increase of 30.5%. Water absorption reduced from 1.7% to 1.6% representing a reduction of 5.9%. Sulphate attack results based on mass and length variation showed that mass and length least increment from 38g to 40g and 5.7 mm to 5.9 mm representing an increase of 5.3% and 3.5% respectively. Electrical resistivity reduced from 13.6 kΩ/cm to 11.6 kΩ/cm representing a reduction of 14.7%. This study proved that addition of crushed waste glass powder to concrete mix at 30% by weight of cement improved its permeability, reduced is susceptibility to sulphate attack although it reduced its surface electrical resistivity. Concrete made with addition of 30% crushed waste glass powder to concrete mix by weight of cement is therefore recommended to be applied in areas prone to moisture ingress, for use as a sacrificial concrete against sulphate attack such as in sewer conduit lining. Further research is recommended to determine the possible causes of the reduction in surface electrical resistivity.