The cement industry contributes around 7% of global anthropogenic carbon dioxide emissions, mainly from the combustion of fuels and limestone decomposition during clinker production. Using alternative fuels derived from wastes is a key strategy to reduce these emissions. However, alternative fuels vary in composition and heating value, so selecting appropriate ones is crucial to maintain clinker quality and manufacturing processes while minimizing environmental impact. This study evaluated various biomass and industrial wastes as potential alternative fuels, characterizing them based on proximate analysis, elemental and oxide composition, lower heating value, and bulk density. Sawdust, pecan nutshell, industrial hose waste, and plastic waste emerged as viable options as they met the suggested thresholds for heating value, chloride, moisture, and ash content. Industrial hose waste and plastic waste were most favorable with the highest heating values while meeting all the criteria. Conversely, wind blade waste, tire-derived fuel, and automotive shredder residue did not meet all the recommended criteria. Therefore, blending them with alternative and fossil fuels is necessary to preserve clinker quality and facilitate combustion. The findings of this research will serve as the basis for developing a computational model to optimize the blending of alternative fuels with fossil fuels for cement production.

This article presents an experimental study to analyze the mechanical properties of a soil stabilized with ordinary Portland cement (OPC) under a sustainable approach consisting of a significant substitution of OPC for sugarcane bagasse ash (SCBA) to reduce the quantity of cement used in the stabilization, reaching the necessary mechanical requirements for its use as a subgrade layer. Soil specimens were elaborated with 3%, 5%, and 7% OPC as a stabilizing agent by weight of the soil. These mixtures were then partially substituted with 25%, 50%, and 75% SCBA, with these percentages being by weight of the stabilizer (OPC). Compaction, compressive strength, and California bearing ratio (CBR) tests were performed to evaluate the mechanical properties of the specimens. The results indicate that a 25% substitution of OPC by SCBA shows a similar performance to the mixture with only Portland cement, so a reduction in OPC use can be made. Further, with a substitution of 100% OPC by SCBA, the CBR of natural soil without stabilizers is improved.

The concrete industry increasingly seeks sustainable alternatives to conventional materials to reduce the environmental impact while maintaining structural performance. This study evaluates the use of locally sourced rhyolite as a coarse aggregate combined with recycled supplementary cementitious materials (SCMs) to address the sustainability and durability. Due to its high silica content, rhyolite is prone to the alkali–silica reaction (ASR), which may affect concrete durability. Concrete mixtures incorporating rhyolite with silica fume (SF), Class F fly ash (FA), and slag cement (SC) were tested for compressive strength, porosity, density, absorption, mortar bar expansion, electrical resistivity, and rapid chloride permeability. All rhyolite-based mixtures—regardless of SCM incorporation—achieved higher 90-day compressive strengths than the conventional control mixture, with 10% SF reaching the highest value. Additionally, each recycled SCM effectively reduced ASR-induced expansion, with 20% FA showing the most significant reduction and superior durability, including the greatest decrease in chloride permeability and the highest electrical resistivity, indicating enhanced corrosion resistance. These results confirm that rhyolite aggregates, when combined with SCMs, can improve durability and reduce ASR. Therefore, rhyolite shows potential for use in structural concrete under standard exposure conditions. This strategy supports circular economy goals by incorporating regional and recycled materials to develop concrete with improved durability characteristics.

The cement industry contributes approximately 7% of global anthropogenic CO₂ emissions, primarily through energy-intensive clinker production. This study evaluates the thermal behavior and gas emissions of seven waste materials (sawdust, pecan nutshell, wind blade waste, industrial hose waste, tire-derived fuel, plastic waste, and automotive shredder residue) as alternative fuels for cement manufacturing, motivated by the limited information available regarding their performance and environmental impact, with bituminous coal used as a reference. Thermogravimetric analysis and differential scanning calorimetry (TGA-DSC) were used to quantify mass loss and energy changes, while TGA coupled with mass spectrometry (TGA-MS) was used to identify volatile compounds released during thermal degradation. Both TGA-DSC and TGA-MS were conducted under oxidative conditions. The analysis revealed that these waste materials can generate up to 70% of coal’s energy, with combustion primarily occurring between 200 °C and 600 °C. The thermal profiles demonstrated that these materials can effectively replace fossil fuels without releasing harmful toxic gases like HCl, dioxins, or furans. Combustion predominantly emitted CO₂ and H₂O, with only trace volatile organic compounds such as C₃H₃ and COOH. The findings highlight the potential of alternative fuels to provide substantial energy for cement production while addressing waste management challenges and reducing the industry’s environmental impact through innovative resource valorization.

The cement industry accounts for approximately 7% of global CO₂ emissions, with fuel combustion contributing 40% of sectoral emissions. Alternative fuels from industrial and municipal waste offer emission reduction opportunities while addressing waste management challenges. This study quantifies real-time gaseous emissions (CO₂, CO, NO_x, and SO₂) from seven alternative fuels—sawdust (SD), pecan nutshell (PNS), wind blade waste (WBW), industrial hose waste (IHW), tire-derived fuel (TDF), plastic waste (PW), and automotive shredder residue (ASR)—during calcination at 850 °C. Bituminous coal served as the reference fuel. Gas concentrations were continuously monitored using the testo 350 portable gas analyzer. Emission factors were calculated on a mass basis (kg/kg fuel) and energy basis (kg/GJ) for standardized comparisons. Alternative fuels consistently produced lower CO₂ emission factors than coal, with biomass-derived fuels (SD and PNS) showing reductions of 45% and 38%, respectively. Most alternative fuels generated lower CO and NO_x emissions per unit energy due to their higher volatile matter content, promoting complete combustion. TDF was an exception, exhibiting 2.8 times higher CO emissions. SO₂ emissions were negligible except in the case of TDF (0.14% sulfur content). The measured emission factors were 15–30% lower than theoretical IPCC values, confirming the environmental viability of alternative fuels as coal substitutes in cement production.