RECYCLING OF WASTE GLASS AS A PARTIAL REPLACEMENT
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Abstract
This research was carried out to investigate the feasibility of using recycled waste glass as a partial replacement for coarse aggregate in concrete. The aim was to evaluate the mechanical,
physical and durability characteristics of concrete containing different proportions of crushed waste glass, thereby promoting sustainable construction practices. The methodology involved collecting, cleaning, crushing and sieving waste glass bottles into
particles of 10–20 mm in size. Five concrete mixes were prepared using a 1:2:4 mix ratio, with 0 %, 10 %, 20 %, 30 %, and 40 % waste glass as partial replacements for granite. All specimens were cured in water for 7, 14 and 28 days. Tests conducted included slump (for workability), compressive strength, density, setting time and water absorption capacity. The results showed that workability increased with higher waste glass content, with slump values ranging from 30mm for the control mix to 60mm at 40% replacement. The compressive strength of 30% replacement after 28 days was 20.30 Mpa, hence it was the optimum replacement level. The density of the concrete decreased slightly from 2.612g/cm3 (0%) to 2.391 g/cm3 (40%), indicating lighter concrete at higher glass content. The setting time test recorded an initial setting time of 65 minutes and a final setting time of 172 minutes, both within standard limits. Water absorption decreased from 1.6% at 0% replacement to 1.2% at 30%, showing improved durability and reduced porosity. From the findings, it was
concluded that waste glass could be used effectively as a partial replacement for coarse aggregate in concrete up to 20% without significant loss in strength or durability.
physical and durability characteristics of concrete containing different proportions of crushed waste glass, thereby promoting sustainable construction practices. The methodology involved collecting, cleaning, crushing and sieving waste glass bottles into
particles of 10–20 mm in size. Five concrete mixes were prepared using a 1:2:4 mix ratio, with 0 %, 10 %, 20 %, 30 %, and 40 % waste glass as partial replacements for granite. All specimens were cured in water for 7, 14 and 28 days. Tests conducted included slump (for workability), compressive strength, density, setting time and water absorption capacity. The results showed that workability increased with higher waste glass content, with slump values ranging from 30mm for the control mix to 60mm at 40% replacement. The compressive strength of 30% replacement after 28 days was 20.30 Mpa, hence it was the optimum replacement level. The density of the concrete decreased slightly from 2.612g/cm3 (0%) to 2.391 g/cm3 (40%), indicating lighter concrete at higher glass content. The setting time test recorded an initial setting time of 65 minutes and a final setting time of 172 minutes, both within standard limits. Water absorption decreased from 1.6% at 0% replacement to 1.2% at 30%, showing improved durability and reduced porosity. From the findings, it was
concluded that waste glass could be used effectively as a partial replacement for coarse aggregate in concrete up to 20% without significant loss in strength or durability.
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