Viola Veronica, Allah Prince, Perumal Priyadharshini, Catauro Michelina
Department of Engineering, University of Campania "Luigi Vanvitelli", Via Roma 29, 81031 Aversa, Italy.
Fibre and Particle Engineering Research Unit, Faculty of Technology, 90014 Oulu, Finland.
Materials (Basel). 2024 Oct 8;17(19):4910. doi: 10.3390/ma17194910.
Alkali activated materials (AAMs) offer significant advantages over traditional materials like Portland cement, but require the use of strong alkaline solutions, which can have negative environmental impacts. This study investigates the synthesis of AAMs using metakaolin and wollastonite, aiming to reduce environmental impact by eliminating sodium silicate and using only sodium hydroxide as an activator. The hypothesis is that wollastonite can provide the necessary silicon for the reaction, with calcium from wollastonite potentially balancing the negative charges usually countered by sodium in the alkaline solution. This study compares raw and carbonated wollastonite (AAM-W and AAM-CW) systems, with raw materials carefully characterized and binding networks analyzed using TGA, FT-IR, and XRD. The results show that while wollastonite can reduce the amount of sodium hydroxide needed, this reduction cannot exceed 50%, as higher substitution levels lead to an insufficiently alkaline environment for the reactions. The carbonation of wollastonite enhances the availability of silicon and calcium, promoting the formation of both N-A-S-H and C-A-S-H gels.
碱激活材料（AAMs）相较于波特兰水泥等传统材料具有显著优势，但需要使用强碱性溶液，这可能会对环境产生负面影响。本研究调查了使用偏高岭土和硅灰石合成AAMs的情况，旨在通过消除硅酸钠并仅使用氢氧化钠作为活化剂来减少环境影响。假设是硅灰石可以为反应提供必要的硅，硅灰石中的钙可能会平衡碱性溶液中通常由钠抵消的负电荷。本研究比较了生硅灰石和碳酸化硅灰石（AAM-W和AAM-CW）体系，对原材料进行了仔细表征，并使用热重分析（TGA）、傅里叶变换红外光谱（FT-IR）和X射线衍射（XRD）分析了结合网络。结果表明，虽然硅灰石可以减少所需氢氧化钠的量，但这种减少不能超过50%，因为较高的替代水平会导致反应的碱性环境不足。硅灰石的碳酸化提高了硅和钙的可用性，促进了N-A-S-H和C-A-S-H凝胶的形成。
