# Impact of Partial Replacement of Cement with a Blend of Marble and Granite Waste Powder on Mortar
## 2 Materials and Methods
### Test Methods for Mortar  
Once various tests were carried out to determine the material properties of cement, fine aggregates, and MGWP, the workability, hardened, and microstructural properties of mortar specimens containing both the control and MGWP were evaluated. The testing was performed in accordance with the test methods and categories outlined in Table 4, which comply with the ASTM standards.  
The workability of mortar samples was examined using the flow test outlined in ASTM C1437 [30], which is a standardized technique utilized to measure the flowability of mortar. A flow table is used to determine the workability of mortar by measuring the percentage increase in the diameter of the base of a truncated cone when it is placed on the table and mechanically raised 12.7 mm (1/2 in.), and then dropped 25 times in 15 s.  
The hardened mortar properties include bulk density, water absorption, compressive strength, homogeneity, and resistance to sulfate attack. To conduct these tests, the mortar mixes were formed into 50 mm \(\times\) 50 mm \(\times\) 50 mm cubes. After molding, the cubes were covered with plastic sheets and stored at room temperature for 24 h. They were then removed from the molds and submerged in water for curing until the time of testing. To determine the amount of water absorbed by mortar specimens containing MGWP during a specific period, the water absorption capacity test was conducted. The procedure involved weighing a dry mortar sample, immersing it in water for a set duration, and then reweighing it to determine the amount of water absorbed. This test is essential because it provides valuable information about the porosity and permeability of the mortar specimens, which can significantly affect their overall durability. The water absorption test was performed on each mortar mixture after 3, 7, 28, 56, and 90 days of curing in accordance with the ASTM C642 [31] standard. The compressive strength tests were performed on the samples in accordance with ASTM C109 [32]. The compressive strength test is a critical test that provides the mechanical property of mortar. It is directly related to the structure of the hydrated cement paste, which makes it an important indicator of the overall quality of the mortar. The homogeneity and integrity of the hardened mortar specimens were assessed using ultrasonic pulse velocity tests in accordance with ASTM C597 [33]. This involved using transmission and receiving transducers to send and receive a timed pulse of ultrasonic energy through the mortar cube. The time taken for the signal to pass through  
Figure 5: Differential thermal analysis of OPC and MGWP.  
the mortar was then analyzed to determine its homogeneity and integrity. In addition, the resistance of the mortar specimens to sulfate attack was determined by measuring the change in compressive strength.  
Thermogravimetric analysis (TGA) and Fourier-transform infrared (FTIR) spectroscopy were utilized to investigate the microstructure properties of MGWP-containing mortar specimens. TGA was performed on selected specimens to evaluate the thermal behavior of the mortar at varying temperatures, determine its chemical composition and stability, and measure its weight loss. On the other hand, FTIR spectroscopy was used to identify and analyze the chemical bonds and functional groups present in the mortar specimens, as well as detect any contaminants or impurities present in the material.