**2. Materials and Methods**

#### *2.1. Materials*

Mortar samples were prepared with ordinary Portland cement CEM I 42.5 R, which complies with the requirements of European Standard EN 197-1. The Blaine fineness of cement is about 4100 cm2/g, and the specific gravity is 3.15 g/cm3. The chemical and mineral compositions of cement are given in Table 1. Chemical analysis of the used raw materials was performed with the XRF method (WDXRF AxiosmAX spectrometer, Malvern Panalytical). The mineral composition was calculated in simple form, taking into consideration the relation between the main oxides in the cement clinker.


**Table 1.** Chemical and mineral composition of OPC.

CEN Standard quartz sand and de-ionized water were used for all mortar mixtures. The glass powder used in this study is a post-consumer by-product derived from recycled white glass (bottles and jars). The glass, after preliminary crushing in the crusher, was ground in a laboratory mill to a Blaine fineness of about 2700 cm2/g. The median particle size of the powder glass is about 20 μm, and the specific gravity is 2.31 g/cm3. The results of the chemical composition of the waste glass analysis are presented in Table 2.

**Table 2.** Chemical composition of powder glass.


The scanning electron microscope images of powder glass are shown in Figure 1.

**Figure 1.** Scanning electron microscope images of glass powder.
