Use of glass bubbles to replace natural aggregates within sustainable cement mixes

Abstract

Glass bubbles are the waste material of some production process. In this study, glass bubbles are added in concrete to replace sand partially. Compressive strength, thermal conductivity and durability tests were carried out to find out the effects of adding glass bubbles. Results showed that a small amount of glass bubbles (20% to 30% of total sand) might have a higher strength of up to 24.8% while having a higher than optimum replacement of sand will result in a lower strength by 32.7% of the control sample. A lower thermal conductivity value of up to 61% was obtained with higher glass bubble content due to more air which is present in the hollow glass spheres. Durability tests of exposing samples to CO2, MgCl2 and MgSO4 at 10% concentration showed that most of the samples will continue to have an increase in strength but the control sample will have a higher increase in compressive strength from day 14 to day 28.