Samadi Mostafa, Murali G, Wong Leong Sing, Din Norashidah Md, Abdulkadir Isyaka, Abdellatief Mohamed, Abdul Shukor Lim Nor Hasanah, Mebrate Zelalem
Institute of Energy Infrastructure, Universiti Tenaga Nasional, Jalan IKRAM-UNITEN, Kajang, 43000, Selangor, Malaysia.
Centre for Promotion of Research, Graphic Era (Deemed to be University), Clement town, Dehradun, India.
Sci Rep. 2025 Sep 18;15(1):32610. doi: 10.1038/s41598-025-20196-2.
The construction sector exerts a profound environmental burden, largely attributable to cement production, which represents a major source of global carbon emissions. In pursuit of sustainable alternatives, this study explores the utilisation of agricultural by-products specifically calcined palm oil leaf ash (POLA) and calcined pine leaf ash (PLA) as novel supplementary cementitious materials (SCMs). Both ashes, when thermally processed, exhibit considerable potential to enhance the mechanical performance and sustainability of cementitious composites. An experimental programme was undertaken to evaluate mortars incorporating 5-30% POLA or PLA, in 5% increments, as partial cement replacements. Mechanical, microstructural, and phase-characterization studies were performed on both fresh and hardened states. Results demonstrated that high replacement levels of PLA (30%) severely compromised compressive strength, With reductions of 72.27%, 69.87%, and 67.64% at 7, 14, and 28 days, respectively. By contrast, equivalent POLA mixtures exhibited more moderate declines of 43.54%, 32.05%, and 32.72% over the same periods. At low incorporation (5%), both ashes fostered compact, homogeneous microstructures enriched in calcium silicate hydrate gel, reflecting robust pozzolanic activity and accelerated hydration. X-ray diffraction and Fourier-transform infrared spectroscopy confirmed these observations, revealing depletion of calcium hydroxide phases and significant modifications in Si-O-Si and O-H vibrational bands at optimal substitution levels. Conversely, excessive ash loadings impeded hydration, with persistent residues, peak broadening, and attenuated CH intensities. Overall, this study demonstrates the valorisation of calcined POLA and PLA as previously unreported SCMs, establishing their potential to reduce cement's carbon footprint while maintaining microstructural integrity and mechanical viability at optimal dosages.
建筑行业带来了沉重的环境负担，这在很大程度上归因于水泥生产，而水泥生产是全球碳排放的主要来源。为了寻求可持续的替代方案，本研究探索了利用农业副产品，特别是煅烧棕榈叶灰（POLA）和煅烧松叶灰（PLA）作为新型辅助胶凝材料（SCMs）。这两种灰烬经过热处理后，在增强胶凝复合材料的力学性能和可持续性方面具有相当大的潜力。开展了一项实验计划，以评估用5%-30%的POLA或PLA（以5%的增量）替代部分水泥的砂浆。对新拌状态和硬化状态的砂浆都进行了力学、微观结构和相表征研究。结果表明，高掺量的PLA（30%）严重损害了抗压强度，在7天、14天和28天时分别降低了72.27%、69.87%和67.64%。相比之下，等量的POLA混合物在同一时期的抗压强度下降更为温和，分别为43.54%、32.05%和32.72%。在低掺量（5%）时，两种灰烬都促进了致密、均匀的微观结构，富含硅酸钙水合物凝胶，反映出强大的火山灰活性和加速水化。X射线衍射和傅里叶变换红外光谱证实了这些观察结果，揭示了氢氧化钙相的消耗以及在最佳替代水平下Si-O-Si和O-H振动带的显著变化。相反，过高的灰烬掺量阻碍了水化，出现了残留、峰展宽和CH强度减弱的情况。总体而言，本研究证明了煅烧POLA和PLA作为此前未报道的SCMs的价值，确立了它们在减少水泥碳足迹的同时，在最佳用量下保持微观结构完整性和力学性能的潜力。
