*3.2. Water Absorption Test*

Water absorption affects the durability of bricks. To conduct this experiment, three specimens from each mixed ratio were selected. Samples were first placed in an oven at 105 ◦C until they reached a consistent density. After being overdried, the bricks were immersed in water for 24 hours. Then, the specimens were removed from the water and cleaned with a damp cloth. The percentage of samples' water content was determined using:

$$\text{Water absorption in }\%= \frac{\text{W2}-\text{W1}}{\text{W1}} \times 100,\tag{1}$$

where W1 is the brick's dry weight, and W2 is the brick's wet weight.

Figure 3 shows the average water absorption results for brick in each mixed ratio. According to the protocol outlined in IS [27], the bricks must absorb no more than 20% of their weight in water after 24 h of immersion in cold water. Figure 3 shows that the water absorption values for bricks were less than 7% in each trial, meeting the IS requirements [27]. A lower rate of water absorption was observed in trail 1 with the increase in the percentage of quarry dust.

**Figure 3.** Water absorption results for brick samples.

#### *3.3. Compressive Strength Test*

The compression test machine measured the dry compressive strength of brick samples. Three random samples were taken from each mixed ratio, as in the water absorption test. The sample's face was subjected to a compression load with dimensions of 230 mm × 110 mm. The compressive strength was determined by dividing the overall load by the original cross-sectional area of the specimen. Figure 4 shows the compression strength test arrangement, and the average compressive strength results are displayed in Figure 5. From Figure 5, it was observed that the composition used in trial 3 achieved the highest compressive strength compared with other compositions used in other trials. However, the compressive brick strength results ranged from 7 to 14 N/mm2, which could be classified as Grade A [28].

**Figure 4.** Compressive strength testing of samples.

**Figure 5.** Compressive strength results for brick samples.
