## 4 Technological Developments of Sulfur in Construction
### Modified Sulfur Cake Bitumen Technologies
Also, sulfur-modified binders allow the use of lower production temperatures, with energy savings of 10 to 20%, translating into both environmental and economic savings [118]. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Indicator**} & \multicolumn{2}{c}{**Modified Sulfur Cake**} & \multirow{2}{*}{**Traditional Bitumen**} & \multirow{2}{*}{**References**} \\  & & **Bitumen** & \\ \hline \multicolumn{4}{c}{Environmental impact} \\ \hline VOC emissions & \multirow{2}{*}{Up to 35} & High emissions & \multirow{2}{*}{[32; 117]} \\ reduction (\%) & & & during mixing and \\  & & & paving \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Critical comparative environmental, mechanical, and economic performance indicators of modified sulfur cake bitumen versus traditional petroleum-based binders. Figure 7: Process steps of the sulfur cake use in sulfur modified bitumen production for road construction. Modified sulfur cake improves the durability of asphalt pavements by increasing resistance to rutting, fatigue, and thermal cracking. Sulfur addition enhances binder stiffness and elasticity, which helps in the provision of high rutting resistance when it is exposed to high temperatures and heavy traffic conditions. More than a 40% reduction in rutting depth of test tracks was realized when sulfur content increased to 20% in the combination of the binder [126]. Fatigue life is also increased by the enhanced flexibility and cohesive strength of the binder and in laboratory tests, 25-30% greater fatigue life has been recorded than with average mixtures [127]. Thermal cracking is a major issue in cold climates, which is mitigated by the improved low-temperature performance of sulfur-modified binders, maintaining the viscoelastic balance without embrittlement [128]. Overall, the use of modified sulfur cake in bitumen not only improves environmental metrics but also strengthens pavement longevity and performance reliability [105]. Using modified sulfur cake to produce bitumen offers large economic and environmental implications that will provide a holistic approach to addressing the issues of sustainability globally. Modified sulfur cake, which is a by-product of industrial wastes from processes like oil refining and sulfur scrubbing techniques, has been crucial in reducing  
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the accumulation of harmful wastes and boosting economic circular activities. This strategy also aids in the implementation of resources, decreases the reliance on landfills, and enhances the reuse of assets between industries through the addition of sulfur-containing wastes to asphalt binder mixtures [121; 123]. The modification and incorporation of sulfur cake in bitumen entails the valorization of a waste stream that would otherwise go unrealized in disposal into the environment. An example is the utilization of sulfur cake, potentially combined with calcium sulfate and other non-reactive products, which can lessen virgin bitumen consumption, an unrefined, fossil-based product with a large carbon footprint. This replacement directly helps the circular economy because a low-value output or even a harmful by-product that would have been discarded is now converted to a construction material [122]. Furthermore, sulfur cake can be mixed with other industrial wastes, e.g., steel slag or phosphogypsum, and form hybrids that enhance the performance of the binders even more and avert the waste of several by-products [124]. In a climate sense, the life-cycle effect of sulfur cake-modified bitumen is significantly reduced compared with conventional petroleum binders. The hot-mix asphalt production and paving procedure is energy-intensive and includes a high level of greenhouse gas (GHG) emissions. However, the sulfur cake that has been modified minimizes the temperatures required during processing by up to 20 \({}^{\circ}\)C and reduces the amount of fossil binder needed, which in turn reduces the emissions of GHGs by about 30 \({}^{\circ}\)C across the life cycle of the pavement [119].