Effect of colloidal nano-silica on the mechanical and physical behaviour of waste-glass cement mortar

This paper presents a laboratory study of the properties of colloidal nano-silica (CS)/waste glass cement composites. The microstructure, alkali–silica reaction (ASR), and the mechanical properties of cement mortars containing waste glass powder (WG) as a cement replacement with and without CS are investigated and compared with plain mortar. In addition, the hydration of cement compounds was followed by differential thermal analysis (DTA), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The results show that incorporation of WG has a positive effect on the mechanical properties of cement mortars especially when CS is presented. In addition, the DTA/TGA results and XRD analysis show a reduction in the calcium hydroxide (CH) content in mortars with both WG and a hybrid combination of WG and CS. This confirms the improvement of mechanical properties and the occurrence of the pozzolanic reaction after 28 days of hydration.

► Glass powder (GP) and nano-silica (CS) were used as a partial cement replacement in cement mortar (CM).
► No damaging effect can be detected due to the reaction between GP and CM with particle size up to 75 μm.
► Hybrid combination of GP/CS greatly improved mechanical properties and microstructure of CM.