# Impact of Partial Replacement of Cement with a Blend of Marble and Granite Waste Powder on Mortar
## 1 Introduction  
The production of cement is a significant contributor to carbon dioxide (CO\({}_{2}\)) emissions, primarily due to the calcination process. During calcination, limestone is heated at high temperatures to produce clinker, releasing CO\({}_{2}\) as a byproduct and contributing to greenhouse gas emissions. Additionally, the fuel used in the kiln, such as coal or natural gas, emits CO\({}_{2}\) when burned. It takes approximately 4.7 million BTUs of energy, equivalent to burning 200 kg of coal, to produce one ton of cement [1]. Consequently, nearly one ton of CO\({}_{2}\) is emitted into the atmosphere as a result of this energy consumption. With an annual cement production exceeding 4 billion tons, the industry is responsible for approximately 8% of global CO\({}_{2}\) emissions [2]. Addressing the issue of CO\({}_{2}\) emissions from the cement industry presents a significant challenge, yet there exist several feasible avenues to investigate. One such approachinvolves incorporating waste materials that possess cementitious properties into cement production. This method offers numerous benefits that extend beyond the reduction of clinker content and associated carbon emissions. Through the utilization of waste materials, it is possible to reduce the need for conventional cement ingredients, leading to the preservation of valuable natural resources. Moreover, repurposing these waste materials that would otherwise end up in landfills fosters waste reduction and diversion, fostering more sustainable waste management practices. Over the last two decades, numerous studies have explored the incorporation of supplementary cementitious materials (SCMs) derived from various industrial and agricultural wastes [3; 4; 5; 6; 7]. According to [PERSON] et al. [8], the marble industries' revenue generation results in the annual production of approximately 200 million tons of waste powder/sludge known as marble processing residue or marble processing rejects (MPRs), which is generated worldwide. Marble production yields a significant amount of waste, ranging from 20% to 30% or even higher, attributed to factors such as irregular shape, smaller size, and cutting and polishing processes. The amount of waste generated varies based on factors such as the type of marble, quarrying techniques, and the processing methods employed. In some cases, the waste generated can reach as high as 60% of the total material processed [9]. Granite waste follows the same pattern, exhibiting significant amounts of byproducts during production, similar to marble waste. In light of the environmental threat posed by the continuous exploitation of marble and granite waste, researchers have examined the potential of waste marble and granite powder, derived from processing plants, to partially replace cement in construction materials. Numerous studies have shown that incorporating marble waste powder (MWP) and granite waste powder (GWP) as partial cement replacements can enhance the mechanical properties of concrete and mortar [10; 11; 12; 13]. According to research conducted by [PERSON] et al. [14], incorporating 10% of GWP by weight as a replacement for cement in normal concrete resulted in an increase in compressive strength from 35 N/mm\({}^{2}\) to 48 N/mm\({}^{2}\). Additionally, the tensile strength of the modified concrete rose from 2.4 N/mm\({}^{2}\) to 3.6 N/mm\({}^{2}\). [PERSON] et al. [12] explored the combined influence of GWP as a partial replacement of cement and magnetized water on the mechanical and durability properties of concrete specimens exposed to two aggressive environments: NaCl and H\({}_{2}\)SO\({}_{4}\) solutions. The findings indicate that when higher quantities of GWP are used, the strength and durability performance of the specimens decrease. This can be attributed to a reduction in cement content and the development of a more porous microstructure, regardless of the type of water used. [PERSON] et al. [15] investigated the impact of incorporating granite dust into concrete.