Development of eco-friendly engineered cementitious composites using glass aggregates: Shrinkage properties

Generally, the absence of coarse aggregate coupled with high binder content in engineered cementitious composites (ECC) mixtures subjects it to high shrinkage despite the presence of fibres. The weak interfacial bond between the fibres and cementitious matrix at early ages results in the ineffectiveness of these fibres to provide restraint in the matrix. On the other hand, there is an imminent need to find alternative aggregate to the conventional aggregate used for ECC mixtures due to its limited supply, high cost and high embodied carbon as a result of its transportation. Recent studies have shown that glass aggregates can be used in ECC mixtures without any detrimental effect on mechanical properties. However, the effects of the glass aggregates on the shrinkage properties of the ECC mixtures are unknown. Therefore, this study was carried out to investigate the shrinkage properties of ECC mixtures made with glass aggregates as the replacement of ultrafine silica sand up to 100%. A total of five mixtures with varying content of glass aggregates were made and the corresponding autogenous, drying and plastic shrinkage was evaluated. Results from this study showed that the use of glass aggregates in ECC mixtures led to a decrease in the shrinkage of the mixtures as the glass aggregate content increases. It is also shown that glass aggregate can be used as a total replacement of the ultrafine silica sand without any detrimental effect on the shrinkage properties of ECC mixtures.