**4. Cost Estimation**

The cost of the waste materials per kg weight, including the shipping cost, was estimated in rupees (INR). The weight of the waste materials used in one brick is multiplied by the unit cost of the waste materials to calculate the total material cost. The cost of human resources and electricity used to manufacture the bricks were also considered. The total cost of brick production in the trials was estimated, as shown in Table 4. It was observed that during trial 1, the cost of production of one brick was INR 3.32, and the production cost gradually increased to INR 3.660 during trial 5. It is noteworthy that although the addition of quarry dust was reduced in each trial, the addition of ESP was simultaneously increased, affecting the cost of brick production. Table 4 shows that the optimum cost for brick manufacturing was the ratio used in trial 3, which indicates high compressive strength results (see Figure 5).


**Table 4.** Cost for production of bricks in each trial.

#### **5. Comparative Analysis**

The manufactured bricks were compared with conventional clay bricks' specifications and manufacturing costs. First, the optimum proportion of manufactured bricks was selected among the different compositions of trials. The results yielded from water absorption (5.4%), and compressive strength (11.063 N/mm2) tests indicate that the composition of trial three was the optimum proportion for producing high-quality bricks; hence, these results were compared with the conventional bricks.

Three random samples of clay bricks were collected from local manufacturers. The manufacturers reported that manufacturing one clay brick ranges from INR 5–6. The same procedures were followed to conduct the compressive strength and water absorption tests for testing the samples. The test results of conventional bricks are shown in Table 5. The average weight of clay bricks was 3.258 kgs. From Table 5, it was observed that the produced bricks were found to be economically feasible, resulting in lower water absorption, higher compressive strength, and lower manufacturing cost compared with conventional clay bricks.

**Table 5.** Test results for conventional clay bricks.


#### **6. Conclusions**

Clay is the primary raw material used in brick manufacturing. However, the use of clay causes erosion and lowers the water table. In this study, an attempt was made to incorporate industrial waste materials into brick manufacturing to avoid using clay. The readily available raw waste materials such as RHA, quarry dust, fly ash, marble powder, and ESP were used in different proportions for brick production. Compressive strength, water absorption, efflorescence, and dimension tests were conducted to determine the quality of the bricks. The results obtained from the tests were compared with the conventional clay bricks. Additionally, the manufacturing cost of bricks from waste materials was compared with clay bricks. The findings indicated that the bricks produced from waste materials were economically feasible and yielded high compressive strength. Future research will focus on performing the sustainability assessment of manufactured bricks from waste materials on economic, social, technical, and environmental aspects.

**Author Contributions:** Conceptualization, K.R. and S.C.; methodology, K.R. and V.C.; formal analysis, K.R. and S.C.; investigation, V.C.; writing—original draft preparation, K.R. and V.C.; writing—review and editing, V.C. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Acknowledgments:** The publication cost of this paper was covered with funds from the Polish National Agency for Academic Exchange (NAWA): "MATBUD'2023—Developing international scientific cooperation in the field of building materials engineering" BPI/WTP/2021/1/00002, MATBUD'2023.

**Conflicts of Interest:** The authors declare no conflict of interest.
